The Equitable Life Assurance Society presents, this is your F.B.I. B.I., the official broadcast from the files of the Federal Bureau of Investigation. Presented transcribed as a public service by the Equitable Life Assurance Society of the United States and the Equitable Society's representative in your community. Good news for fathers and mothers who want their children to have a college education. When paying for that education has been made practically painless, that is good news, isn't it? The plan that makes this possible is called the Equitable Education Fund. It's the way to provide a college education for your boy or girl so that not even death of a family breadwinner can interfere. Be sure to listen carefully when the Equitable Life Assurance Society gives you the full details on the Equitable Education Fund, about 14 minutes from now. Subject of our F.B.I. file, Arm Robbery. It's title, The Curious Fisherman. Tonight's case was selected because it points up a warning that your F.B.I. has issued many times on this program. This warning is, don't publicize yourself as a promising victim for a crime. The underworld finds it highly profitable to scan newspapers carefully, to circulate unobtrusively in public places. The man who openly displays a well-filled wallet invites a pickpocket. The woman who allows herself to be photographed wearing costly jewels may be setting the wheels in motion for a carefully planned robbery months later. Tonight's case from the official F.B.I. files is dramatic proof that public display of wealth can be an invitation to crime. Tonight's F.B.I. file opens on a small fishing boat tied to a pier on the outskirts of a western city. The hot noon sun burns down on a leather-skinned man as he approaches a young girl mopping the deck. Well, you put down the mop. You keep working like that, you know what'll happen? No. You'll weigh yourself down. Your mother'll never let you spend another vacation on the Blue Queen. But she has to. Why? I stopped biting my nails. The way I heard it, that just took care of this vacation. Oh, but I won't bite him again next year. You're all right. Now can I finish swabbing the deck? You better get some lunch first. What should I make? Well, now let's see. Should we have oysters, Rockefeller or a juicy steak? Should I open a can of beans or hash? Now I'll have to do some deep thinking about that. Uncle Fred, some customers. What? Those folks on the pier, they're heading this way. Well, not dressed much for fishing. Your party yesterday wasn't either. Well, I'll talk to them, honey.  This is my friend here. We'd like to do some fishing. You come to the right place. Oh, that's fine. We want to go out tomorrow. I'm for hire. He's for hire. How about it, mother? Looks like a nice boat. The Blue Queens are right. Nice boat, ma'am. Floyd, you game for fishing tomorrow? Sure. Well, we got to make a sit. Oh, be free tomorrow. You see, we're on a vacation. And never so busy as when you're taking a rest. Lots of folks like that. Yeah, say, have you got a camera? Nope. Well, suppose we catch one of those big babies. You know, the folks back home, they'd want to see a picture before they believe that we really caught one. I'll pick one up. Just you three going? Yeah. Well, be $50 for the day. I supply everything. Just say the time and I'll be ready. Well, how's nine o'clock? Early or if you like. Earlier, no. Let's wait until the fish are up, too. Now, see you at nine, Captain, and bring plenty of bait. You know, we might catch you where. Finish your breakfast. I did. Now, what about the milk? Oh, Uncle Fred. I promised your mother you'd have a glass of milk for every meal. I'll take two for lunch. Well, all right. You're the best uncle a girl ever had. Oh, here comes our party. I'll go start the motor. Take your time. Yeah. Well, here, take my hand. Be up this early. As long as you don't overdo it. Yeah, watch your step, lady. Thank you. Hey, armistice. All right. I don't need help. Why don't we put up poles? What'd you bring poles for? Well, we're going fishing. Sorry you took the trouble. I thought I told you the price covered everything. Oh, we got them, so we might as well use them. We can leave whenever your party's ready. We're ready now. Hey, what's that? A motor. Oh, who started it? My niece. Oh, get her ashore, huh? Ashore? She's my crew. Not this trip. Well, before I forget it, she won't make any difference. Leo is right.  Well, I don't like kids. All right, Mr. I'll go. Alice, you stay here. It's her or us. I'll take her. Uncle Fred, it's $50. Take them. I don't care. I pick out my own crew. Go ahead. I don't feel like fishing today anyway. Now can we get started? Yeah, sure, dear. All right, Skipper, over the bounding main. This is the life. Yeah, not for me. Look, Floyd, you've got to learn to relax. Enjoy yourself. Why? Leo, something's gone wrong. I don't see the Mary Ann. Leo, are you sure you got the right information? Well, of course. Do you know I never make a mistake? Go back there. Answer him. Yeah, Skipper, now not yet. Hey, I think that's it. Yeah? Wait till I read the name. There can't be too many yachts around here. There's enough. It's the Mary Ann. I told you we'd need her out here, didn't I? All right, then.  Okay, I'll move that chair so I can lay down. Fine. All right, start growing. Hey, Skipper. Skipper! Yeah? Come here, quick. Well, my wife, she's taken sick. Will you get us out to that yacht? Maybe there's a doctor aboard. We'd be better off turning back. But I got first-aged stuff aboard. Oh, please, will you? She's very sick. Head for the yacht. A short while later, at a nearby FBI field office, special agent Jim Taylor is at his desk when the phone rings. Taylor speaking. Jim, this is Sheriff Webster. Oh, hello, Sheriff. I'd like some help down here. Why? What can we do for you? A yacht named the Mary Ann called in Jim. Said she'd been boarded by two masked men. Oh, where? Oh, who's the Mary Ann registered to? A man named Forrest. Sheriff, any other ships in that area? Video. And still no answer from the yacht, huh? That's right. I'm setting up our plane now to search for her. Well, OK, Sheriff. I'll be down on the first train. There is a beautiful ring. Let's see it. Oh, just keep stirring. You can see it at the hotel. Before I take the wheel. No, I can't. I'm cleaning my gun. It got wet. Hey, look, there's the pier. I think I'll keep this ring. Hey, Leo, swing over. You're going to hit the pier. Hey, good. Are you OK? Yeah. Come on. The pier. Hold it. Yeah. No answer. What'll I say? Never mind. Your uncle's in the cabin. Why? Isn't he going to tie up? Ask him. It's his boat. Take care of him. Anything convenient on my yacht? Our plane located her and landed alongside. Good. We were right about the radio equipment being smashed. The bandits took care of that first. How much they steal, Sheriff? $20,000 in jewelry. Wow. We didn't get descriptions on either of the men, Jim. We got a good one of the getaway boat. She's a fishing craft named the Blue Queen. About a 35-footer painted blue with a white star stern. Uh-huh. Where's she registered from? Here. I know her owner. His name's Barrow. She's usually at her dock by now, but I checked. And the pier's empty. Couldn't the victims give you any description of the men? Just that one was fat. They wore masks made of an off-white silk. Uh-huh. And there was another man and woman in on the job. They stayed aboard the fishing boat. Oh. The fishing boat pulled up alongside the Mary Ann.  They asked for first aid equipment and were invited to come up a rope ladder and get it. So the woman was in on the job, huh? Now, how about the man who stayed aboard the fishing boat? No description on him either. Well, maybe that was Barrow. Oh, I doubt it, Jim. I've known Fred a long time. He wouldn't be mixed up in anything illegal. Besides, this was no amateur, Joe. No, it certainly doesn't sound like one.  That's understandable. But she wasn't wearing them, Jim. She said she didn't have anything like that. But the bandit told her he saw her wearing them in some picture. In a movie, you mean? No, a newspaper picture. Oh, I see. So I've arranged for us to use the launch. Want to see if we can locate the blue queen? You mean at night, Sheriff? Weatherman says the moon will stay this bright. Oh, OK. Let's give it a try. What are you doing on this side? Our good, Sheriff. We can't stay out much longer. Gas running low? Mm-hmm. You know, that moon's not as much help as we figured. I can't take much more of that reflection. Oh, it's pretty rough. We may have to wait till morning. Great, sir. Hm? Look over that way. Where? Out there on the left. Oh, something there. Yeah. Part of the port side. It sure looks like a boat. Uh-huh. It is. Yeah. Jim, there's the white star on the stern. Yeah, that must be the blue queen on it. Nobody's on deck. She looks like she's drifting free. Cut your motor and hook as fast. It doesn't seem to be any life aboard. Ah, blue queen. Anybody aboard? Cover me, Sheriff, huh? OK, Jim. Go ahead. Sheriff, come on over. Uh, let's see if there's anything in the cabin here. Right away, Sheriff.  Oh, it's Barrow's niece. Is she usually aboard? Summers. Let's have you light a minute, huh? Sure. Kids get a bad head wound. Uh-huh. How about moving over to the launch? Yeah, well, let's cover the rest of the boat first quickly. OK. Uh, poor kid. What's that on the deck there? Scraps and material. Looks like silk. It's white. It could be the masks. Uh-huh. Looks like parts of a shirt. Yeah. I don't get this. Where is everybody? It's in the cabin. I doubt it. Didn't you say they were armed? That was the report. Well, if they were aboard, they'd have heard us approaching. That's so. Wait a minute. Hold it. Hm? I thought I heard something. From the cabin? Yeah. Wait here, Sheriff. Come on. There were your hands up. No pulse. No heartbeat. Well, Sheriff, we're working on a murder now. In just a moment, to tonight's exciting case from the official file of your FBI. Now, for a moment, let's listen to a professional worrylifter in action. His name is Fred Barton, a representative of the Equitable Life Assurance Society. And his job is to help men and women get rid of some of life's major worries. Fred Barton is talking to a young father named Jim McClain. Well, what worries me, Mr. Barton, is when my kids are both in college together, boy, will I take a beating financially. Well, you don't need to take a beating, Mr. McClain. Not if you start an equitable education fund. Equitable education fund? What's that? It's the painless way to pay for a college education. Actually, it's an endowment life insurance policy with the Equitable Society.  Well, like paying for it on the installment plan, only doing it in advance. That's it, exactly. Installments are the sound way to finance any major family expense, like buying a house, a car, or household equipment. That's the basic idea of the Equitable Education Fund. Spread the payment so they don't hurt.  No further payments are necessary. Well, how many years does it take to pay up one of these funds? Well, that's up to you. But starting when your children are young makes the yearly payments lower for you. Well, it all sounds attractive, providing I can afford it. Well, you leave that to me, Mr. McClain. Just figure out what you can afford to put into a plan like this. You'll be surprised how small payments wound up when you keep at it for 15 years. For instance, at your age, a $4,000 equitable fund... If you have children of your own, why not get the cost of an Equitable Education Fund from your equitable representative? These equitable men give you the information you need and let you make up your own mind. Get in touch with your equitable representative or right care of the station to the Equitable Society. That's E-Q-U-I-T-A-B-L-E. The Equitable Life Assurance Society of the United States. Now back to the FBI file, The Curious Fisherman. Captain Barrow is dead. Murdered by criminals, he accepted as ordinary fisherman. Naturally, a man in his position cannot be expected to ask every prospective customer to identify himself. The fact remains, however, that people whose business it is to deal with strangers should be constantly on their guard. Tonight's skipper might have been more cautious. The men's refusal to have a girl on board. Their obvious ignorance of fishing know-how should have struck him as extremely suspicious. Your FBI files abound in cases similar to this. Cases in which the victim's readiness to accept strangers at their face value has contributed to his own undoing. Tonight's FBI file continues two days later at Sheriff Webster's office. Special Agent Jim Taylor hangs up the phone. Sheriff, that was the lab. What'd they say, Jim? Well, that silk we found aboard the fishing board didn't carry any invisible laundry. Sure looked like parts of a shirt. The lab says they are, and that from the quality of the silk and the hand stitching, it must have been custom made. It doesn't help much. How many custom shirtmakers are down here? Oh, a dozen or so. Well, maybe one of them would recognize the material, huh? I'll try. Okay. Here's the swatch, Sheriff. I'm gonna run by the hospital and see if Barrow's niece has come to you. The hospital call? No, but I'm gonna be out that way. I've got an appointment to interview one of the women and the woman who was robbed of the jewelry the bandits saw wearing in a picture. I went through the files of both local papers this morning. Neither of them has ever printed her picture. Oh, I'll call in when I'm through. Hmm? Oh, I don't know. Stop ogling those dames in the pool and answer me. He went to see the fence. What did he do with my ring? Huh? The one I liked. Oh, he took it. What for? To sell. After I told him not to? Uh-huh. Well, just wait till I see him. I'll straighten him out. Uh, don't tell me. Tell him. I will. There's your chance. Oh. When you hear the deal I made for us. Leo, did you sell that ring? Yes, honey. Don't honey me. I told you I wanted it. Look, honey, the cops are gonna be looking for all that stuff. If they found it on you, then I'd go to jail. That's not a bad idea. How much you get? At $11,000. It was worth more. Well, that's all he'd pay, so I took it. You got the cash? No. I'll leave it to collect the day after tomorrow. Where? In the lobby. We collect and then we rest. Not too long. Uh-huh. I got another job all laid out for next week. Got bad news on that silk. No shirtmaker use it? Not now or ever. Yeah, that is too bad. How'd you make out with your interview? Well, sure if that woman's only had her picture in the paper once in her life and that was with the jewels. Which paper? Crystal City Journal. That's her hometown. Maybe it's the bandits, too. Yeah, could be. How long ago was the picture printed? Last year. I called and had our lab ship a sample of the silk to our resident agent at Crystal City. There must be plenty of shirtmakers there. Well, I just hope not too many use this material. How soon can we have an answer? Well, the sample went out air mail last night, so it's in Crystal City this morning. Fine. Hey, tell me, you have to stick around here. No, why? Well, the little girl's doctor told me that if we came by the hospital this morning, we could see her. Maybe she can give us a description on the bandits. Well, let's take along the jewel theft album and find out. Alice, you too tired to continue? No, Mr. Taylor. All right, honey, go on. Well, then when I went aboard to see Uncle Fred, one of the men hit me. Which one? The strong one. You're not going to let him get away, are you? I'll sure try not, sir. I'll help you. Quicker. The doctor said I can get up tomorrow. Oh, that's fine. Alice, you want to go through these pictures again? It's no use. They're not in here. Can Uncle Fred tell you what they look like? No, no, he can't. I only saw him for a couple of minutes, but he was with them all day. Do you remember anything at all about the woman? Just what I told you. She was blonde. I liked her at first, but she stuck up for the strong one when he said I had to get off the blue queen. Was she pretty? Uh-huh. But she uses too much mascara and lipstick. Did any of them dress so you'd remember? No, they were dressed regular. Well, Alice, the doctor asked us not to stay too long, so I guess we'll be going out. Oh, it's all my fault. I know that's what Uncle Fred had the fight with him about. You're sure he's not mad at me? No, Alice, he's not mad at anybody. Come on, Sheriff. Sheriff, I just heard from Crystal City. What'd they say, Jim? Well, a shirt maker there used that silk last year and then discontinued it. He supplied the names of six men who got shirts from that bolt. Five of them are legitimate people still living there. Who's number six? He's a man named Leo Spencer. His shirts were delivered to his hotel. The register showed that Spencer and his wife stayed in Crystal City for about a month, and they were there when the victim's picture was published. Sounds like he's our man. Where's he from? Well, that's where we run out of gas. The address he gave is a municipal swimming pool. The shirt maker remembered Spencer, though. He said he's kind of short, very heavy. The fat bandit. Now, it looks like him. Well, he ordered two dozen of those shirts at $30 each. Washington got any record on Spencer? No, I called I didn't when Crystal City reported in. Then we're still without a lead and running out of time. I know that thieves might have had the stones reset. That's right. That'd give Mr. Spencer or whoever he is enough to get some new shirts. Wait a minute, Sheriff. New shirts. He shouldn't need any new ones. Well, he just got two dozen last year. Now, silk shirts don't wear out that fast. Say that's so. Well, if we're right so far, we might still have a chance. Is Leo still making that call? Uh-huh. That fence must be in Europe. I hope he ain't. What time is it? It's, uh, 10 after. Well, he's not too late anyway. Well, here comes Leo. Oh, good. There's no answer. He must be on his way. Pardon me. Yeah? Is your name Leo Mason? That's right. Leo, is this him? No, no. I'm a special agent of the FBI. Here are my credentials. Well, what do you want from me? Information. Are these the two people who worked on that fishing boat with you? Uh, Leo, I got to run. Just a minute there. Huh? Who's he signaling to? How should I know? The kid. That's him, Mr. Taylor. All three of them. Thank you, Alice. Why, you little... Oh, none of that. I've got him, Jim. Okay, Sheriff. Now let's take them in. Martha Mason and Floyd Scott were convicted in federal court for murder on the high seas and sentenced to life imprisonment. Special Agent Taylor and Sheriff Webster arrived at the correct hotel because a certain laundry recognized the odd swatch of silk. They were at that time cleaning three shirts made of that same material. Three shirts for a man named Leo Mason at the Star Hotel. Tonight's case from the files of your FBI is a good illustration of how slim a thread of evidence is often all the police have to work with. It is also a good illustration of another important point. That's so long as there remains the vestige of a lead. Neither your FBI nor any good law enforcement agency will ever stop working. Will ever stop until the criminals have been apprehended. And justice done. Quick review of the advantages of an equitable education fund. First, it's the painless way to pay for a college education. You spread the cost over many years instead of taking a beating in four. Second, it's sure.  So why delay?  All right, care of the station to the equitable life assurance society. Next week, we will dramatize another case from the files of the Federal Bureau of Investigation. It's subject, subversive activities. It's title, The Interrupted Journey. The incidents used in tonight's equitable life assurance societies broadcast are adapted from the files of the Federal Bureau of Investigation. However, all names used are fictitious, and any similarity thereof to the names of places or persons living or dead is accidental. Tonight, the music was composed and conducted by Frederick Steiner. The author was Jerry D. Lewis. Your narrator was William Woodson, and special agent Taylor was played by Stacey Harris. Others in the cast were Sheldon Leonard, Paul Richard, John T. Smith, Naomi Stevens, Tom Tully, and Ann Whitfield. With your FBI, a Jerry Divine production was directed by Sid Goodwin. This is Larry Keating speaking for the Equitable Life Assurance Society of the United States and the Equitable Society's representative in your community. And inviting you to tune in again next week at this same time, when the Equitable Life Assurance Society will bring you another thrilling transcribe story from the files of the Federal Bureau of Investigation. The Interrupted Journey on This Is Your FBI. Stay tuned for a life in your hands starring Lee Bowman, which follows immediately. This program came to you from Hollywood. America is sold on ABC, the American Broadcasting Company.


Minister of Works or State Works and House in Abu Bakr, Aliyus says the federal government had reformed that 143 billionare to five state for constructing federal roads. He made the disclosure during a visit to Governor Artico Baguto of Kebbi State at Government House in Burnin Kebbi, the state capital. The minister was in Kebbi to ascertain the level of work executed by the state government on the construction of some federal roads in the state. He records that President Mohamed Buhari had given approval for the payment of 477 billionare which was shared among the 25 states respectively.


Hello, welcome back today we will quickly summarize for you the oxygen transport ok. You have seen this oxygen transport before, but in different places let us put it in one basket and try to make things easier for you for example purpose ok. You have seen oxygen transport happening in case of hemoglobin where we have a heme iron center, you have seen it is happening in hemorrhithrin where you have two non heme iron centers and of course, you have seen in hemocyanin where you have two copper centers present. Let us try to put it in one place and see their differences. We will also see a very little example or some selected examples of the synthetic model system that exist to mimic these oxygen transport enzyme. Hemoglobin and myoglobin is first up. So, in myoglobin you have seen there is a porphyrin center and there is an axial site which is bound with the porphyrin site porphyrin iron center and at the distal center oxygen binding is happening right. This is one heme center. In case of hemoglobin there is four such heme centers present there is a allosteric effect or one oxygen binding is affecting the oxygen coordination of the others ok. You have seen the sigmydol carb for the oxygen binding into the heme centers. So, that is all fine heme hemoglobin versus myoglobin difference is it is four iron center in case of hemoglobin and one iron center in case of myoglobin that is fine. You have seen a tabulated format of which differentiate hemoglobin and myoglobin in the in the previous class ok. Now, binding of oxygen to porphyrin 9 we have seen it is also quite exciting. You have seen the spin change from high spins compound to low spin compound you are forming. You have a ferrous means iron 2 plus oxidation state and you have ferric that means iron 3 plus oxidation state upon oxygen binding this porphyrin iron species goes to iron 3 plus superoxo intermediate which is then forming the low spin ferric compound right. So, this is iron 2 plus it is outside the plane it is not really inside the plane high spin ferrous ok and this is this is the histidine binding. Remember for cytochrome P450 where oxygen activation is coupled with substrate activation as well as substrate oxygenation chemistry is happening there it was a cysteine ligand not the histidine. So, that cytochrome P450 here we are discussing about the hemoglobin and myoglobin cases. This is histidine, histidine axial chain as you can see the high spin ferrous that means Fe 2 plus D7 iron system high spin would mean T2G4 and EG2 right. So, iron 2 plus means this the 6 electron systems sorry and D6 electron system would be this T2G4 and EG2 system fine. Now, let us look at the low spin ferric of course, this is a iron 3 plus that means, it is a D5 electronic system since it is low spin it is going to be T2G5 this is a superoxo. How do you know it is superoxo? Very simply if you want you can record every visible spectra which is characteristics of it and you can also record resonance Raman which is kind of definitive proof that it is superoxo species. You have seen for myoglobin cases it would be 1105 wave number for the oxygen-oxygen stretch in resonance Raman that means, that it is without doubt this is the iron 3 superoxo species right that is fantastic that is a superoxo species right over there and this oxidation state change as well as spin state change you have seen very clearly ok. Now, this phenomenon you can follow in the enzyme in the form of let us say crystal structure this is a nice crystal structure showing that iron 2 plus is outside the plane histidine is bound once again if it was cytochrome P450 here you would have 16 bound with it right. There is a there is many protein residue or these backbone from the amino acid backbone of the protein residue which is coming into the picture in the distal site all these are appended towards this active site giving rise to a great feeling for this oxygen binding ok. Once the oxygen is binding with iron of course, at the first step there will be oxygen binding without any electron transfer, but immediately after that immediately after oxygen binding one electron from the iron center transferred to the oxygen to make it iron 3 plus superoxo you start with iron 2 plus you went to iron 3 plus superoxide species. This species is also affected by this protein side backbone or protein side chain which overall helps in giving the geometry it is having that is the bent geometry and this is particularly why we see that the role of these histidine phenyl aniline and leucine are quite crucial for the oxygen binding ok. Now we also understand that this histidine will move in as soon as this iron center moves in the cavity this histidine also moves in side this pull or this trigger will cause a trigger for the other iron center other 3 iron center that is present in case of hemoglobin to make them activate to make them ready for the oxygen binding. So, one oxygen binding at the one of the iron center helps binding other iron with the oxygen center. So, this movement from this outside plane to inside plane this overall upward movement for the histidine is quite important. As you have seen for in case of cytochrome P450 here it would be cysteine. Now this cysteine thiolate will help you overall in breaking the oxygen oxygen bond in case of that hydroperoxo OOH that is being formed and then overall this iron oxo species subsequently after oxygen oxygen bond cleavage whenever it is happening that is in cytochrome P450 this iron 4 oxo or this high valent iron oxo species that can be generated in cytochrome P450 it will be stabilized or it will be really easy for cytochrome P450 to have this cysteine which can stabilize such an intermediate ok. So, once again these there are similarities between hemoglobin and cytochrome P450 cytochrome P450 not only activates the oxygen it actually also activates the substrate to do the chemistry. In case of hemoglobin and a myoglobin cases it is purely oxygen binding right, you do not see any you do not see any other reaction happening at the hemoglobin and myoglobin and that is partly because and of course, the partly because of the presence of these protein side chain and absence of any substrate and the substrate binding pocket. Once there been a substrate binding pocket and a substrate available then we perhaps will not be living here because these are the reason why we inhale oxygen and how we take up those oxygen and deliver at different part of the body. If this oxygen was involved into activity such as substrate hydroxylation chemistry we will not have been getting these oxygen at different part of our body which is essential for surviving different cells. So, therefore, with this whole system perhaps our whole system biological system perhaps would have collapsed. So, as you see nature has designed everything perfectly that in this case it puts or it engages a histidine as opposed to the cysteine and more importantly substrate binding pocket and non-availability of substrate makes it perfect for it for hemoglobin iron center protopropyrin 9 center to act as just oxygen transport agent or center it is not really participating in anything else its role is to reversibly bind. So, whenever it is required it can bind and it can release oxygen. So, if this is the porphyrin center oxygen can come in and binds with it of course, there is a super oxo formation after electron transfer, but wherever it is required it can release the oxygen. So, it is almost keeping the oxygen watching the oxygen, but it does not engage oxygen too much into the reactivity it is not like it cannot it is capable of doing it, but overall architecture is such that it is just participating in oxygen binding and removal. This reversibility is so good that you do not see any loss of activity in these cases. If you want to do the same chemistry in synthetic setup it is not that very easy we have discussed that we will briefly mention that again. So, the problem that happens with the synthetic chemistry is well the moment one iron center is bound with one oxygen, another iron center is also approaching it to form the iron 3 peroxo iron 3 species. So, it would be in between as you have discussed earlier it will cause problem let me briefly mention once again and that is you will end up seeing. So, the moment you have a iron 2 porphyrin system let us say P it reacts with oxygen to give you let us say this is leveled oxygen if you are leveling to give you iron 3 super oxo species that is the first form species this is the super oxo species radical cation. So, it breaks it breaks to give you iron 3 super oxo species subsequently from there another porphyrin iron 2 species comes in and it gives in one electron to it and essentially it gives porphyrin iron 3 oxygen, oxygen and iron 3 porphyrin species right. So, these species is now then can further react. So, in case of enzyme it stabilizes over here there is no problem because there is not the second iron center or second porphyrin center is not really available because enzymes are protecting every site very perfectly. But in synthetic studies when you are trying to do this chemistry in laboratory you can get this chemistry, but you can of course, get this chemistry, but this is not limited or this is not staying right over there it can further react with another equivalent of porphyrin iron 3 which is present into the solution and can give the peroxo species. So, this is the iron 3 oxygen, oxygen and iron 3 peroxo species this species of course, also reactive further it can go on and react and finally, it will perhaps stop reacting at this point when you have this iron 3 iron 3 oxo or mu oxo porphyrin iron 3 this is relatively stable compound. So, it is goes there you can see that this is kind of a thermodynamic sink right. This is not what you want you want these to be reversible and it stays over there that that is what is happening this all this reversible chemistry is happening in enzyme. The first in enzyme case this is where it gets stabilized, but in synthetic chemistry setup you end up getting these side reaction which causes the majority of the problem and therefore, mimicking this chemistry in synthetic setup is extremely difficult because we want to mimic just the reversible binding we do not want to get any reactivity out of it. We do not want to react it with any other substrate or anything because we want to see the hemoglobin chemistry which is the reversible oxygen binding right. In synthetic setup most of the studies that has been done so far fails to mimic this reversible oxygen binding completely because it not only does this chemistry, but it over reacts right this is the problem of course, it is possible to mimic, but it over reacts and therefore, it leads to the side product formation right. So, let us go back so, to prevent these over reaction or even the auto oxidation of iron 2 plus to iron 3 plus which is again another problem because this iron 2 plus stabilizing them in iron 2 plus is very difficult because it is very sensitive, it is air sensitive and moisture sensitive all these species need to be recorded or need to be stabilized stored in glove box right. This is very sensitive chemistry. Now, to prevent that second iron center to come close to the first iron center where a superoxo species is forming it has been successfully designed to have this picket fence for firing which is essentially helping you in in getting the mono nuclear. So, mono nuclear iron superoxo species these oxygen binding are reversible in nature in this case you see that axial ligand is also there in the form of imidazole which is similar to what we see in histidine right. So, this picket fence for firing can mimic the reversible oxygen binding of the hemoglobin also there is this capped porphyrin as you see it is a really nice drawing and really nice molecule where as if there is an umbrella in front of the iron side which is protecting from another molecule of these to come very close to each other. So, this proximal site is blocked by the histidine and the distal site is open where oxygen binding can happen and oxygen binding once it happens this intermediate which is very reactive intermediate despite having high reactivity of this iron III superoxo it still does not really react with another equivalent of this molecule due to the steric hindrance or the bucket shape of these species right. So, this overall umbrella thing or umbrella design helps in stabilizing the intermediate perfectly. Now that is what we have seen. So, in hemoglobin and myoglobin cases you know that there is no substrate activation it is purely oxygen binding right. It is a reversible oxygen binding after much effort synthetic chemist can mimic those features of hemoglobin and myoglobin. By mimicking or by copying the activity of the hemoglobin myoglobin it gives an opportunity to better understand what happens in hemoglobin and myoglobin even at a molecular level things can be done which were not otherwise possible. The problem of the dimerization or the dinuclear iron species formation can be prevented somehow by putting this big picket fence or cap porphyrin design. Let us look at another enzyme that is hemorrhithrin before that just to mention once again this is 1105 wave number for oxygenated myoglobin this is matching quite well for the superoxo species ok. If you have a crystal structure that can also give the oxygen-oxion stretch in this region which is quite exciting in any case ok. Let us look at the hemorrhithrin as you have seen hemorrhithrin is a diiron center ok these are non-hem centered. So, hemoglobin is found in some like let us say in higher species such as us in all other mammals in you know majority of the species are having hemoglobin but then there is these marine invertebrates and some other species where you do not have the hemoglobin cases where you have you do not have the hemoglobin iron oxygen binding center and this is where these iron 2 diiron center will be coming into picture. These are not porphyrin ring or these are having these histidine simple histidine ligation. These histidine ligation are quite phenomenal quite important because it provides the opportunity for these species to carry oxygen invertebrates to carry oxygen. Before oxygen binding it was a colorless species upon oxygen binding. So, colorless species this one upon oxygen binding it becomes red. So, this is a red color species this oxygen binding just like hemoglobin and myoglobin is reversible in nature that means, it is pretty easily can go forward and backward and therefore, the oxygen transport and release can be easily possible right. If you are looking at this species so, this species will form a peroxo species let me draw it very quickly. So, what you will see here is it is you are having a diiron center right I am not drawing bridging too much. So, it is a diiron center you are reacting with oxygen let us say level the oxygen you get a diiron. Of course, I will draw stepwise not necessarily these intermediate you form and stabilize very easily you of course, it is forming, but you cannot stabilize showing the first step it is a iron II iron III species or only one of the iron site will bind this oxygen because the other side as you have seen is having 3 histidine, nitrogen, nitrogen, nitrogen these are histidine, nitrogen the other side is having only 2 nitrogen histidine histidine right. So, of course, there is bridging I am not trying to draw those there is a double bridging anyway. So, these are over there oxygen oxygen let us not try to draw the whole system. So, this is this is unsymmetrical iron center as you have seen over here you have a iron II plus center with 3 histidine on this side it is 2 histidine right and then you have the oxygen molecule in there right. This oxygen molecule binds with it one of them the one which is unsymmetrical or which is having less ligand this is 3 histidine ligand this is having 2 histidine ligand. So, this is the site where oxygen binds and upon binding the oxygen it can then through the bridge since it is through the bridge it can. So, of course, this intermediate you cannot see you cannot see such intermediate this is iron III superoxo intermediate perhaps it is going to be extremely difficult to stabilize. So, immediately another electron transfer happens to it to give to give you a peroxo intermediate. So, as you have seen this is going to be 2 minus the whole thing is going to be 2 minus. So, this was 1 minus superoxo this is a superoxo this is a peroxo of course, just remember that it is not really possible to see such intermediate just I am drawing step wise for your clarity or for you to understand very simply. So, both the iron II plus center give 1 electron at a time to give the iron III peroxo species. This iron III peroxo species subsequently can be protonated as you have seen over there. So, this is going to be a completely proton transfer. So, proton coupled electron transfer perhaps in this step this is going to be at a step not even this intermediate you will be seeing. So, overall you will be seeing the formation of iron III oxo iron III hydro peroxo intermediate right. So, this is your oxygen that is coming on this is your oxygen from the oxygen atom and there is a hydrogen bonding and rest of the things are still there still there ok. So, I do not think it is fair to draw the intermediate because not such intermediate existence is questionable both the intermediate. So, iron II iron II you start with immediately you get iron III iron III hydro peroxo. So, this is a proton transfer the way I have shown you is electron transfer first and then proton transfer perhaps that is not going to happen it is going to be proton coupled electron transfer directly it is forming. So, one electron from this side another electron from that side it makes it iron III iron III peroxo and then protonation. So, immediately all of them are happening. So, it could be one electron transfer and one proton coupled electron transfer PCET that is what is happening. Stepwise drawing this mechanism is not perhaps fair because no such intermediate exist and you know we cannot say for sure what exactly happens in a stepwise fashion. But as you have seen as you have seen over here you can see that this is hydro oxo intermediate and upon oxygen binding it forms these from iron II iron II iron III iron III hydro peroxo intermediate which is hydrogen bonded through this mu oxo species right. If you try to record the resonance Raman of this oxygen-oxygen stretch you find that it is at 844 wave number which is matching perfectly for the peroxo species. So, in the first place of hemoglobin myoglobin you see that it is a iron III superoxo species it is formed of an oxygen binding it does not go anywhere after that. But in case of hemorrhoid thin it is one more electron reduced species and protonation that is iron hydro peroxo species it is a di-iron species and it is a bridge species that is quite phenomenal. I think pretty exciting intermediate and these species are spectroscopically characterized and you can see the spectral behavior right over here right. So, let us move on and try to see what we can get in case of the synthetic modeling studies. As you have seen in the synthetic modeling studies it would require the 3 histidine on one side or 3 nitrogen binding on one side another side would have 2 nitrogen binding synthetic chemists has been very efficient in mimicking this and it was possible to mimic almost exactly the spectral feature. So, synthetic chemists have been extremely successful in mimicking this activity and we see that it is possible it is actually possible to get the exact 3 histidine or 3 nitrogen binding on one iron site another iron site will have the 2 nitrogen binding and the hydro peroxo species formation oxygen oxygen stretching and all the other spectroscopic features evavisible MOSBOA spectra are exactly similar to what is found in the enzyme that is fantastic and these are completely reversible oxygen binding in the enzyme that is fine. So, you have seen the difference between hemoglobin and hemorrhoid thin. Let us quickly look at the hemocyanin as you have remembered perhaps it is a 2 copper or it is 2 copper center as opposed to 2 iron center in hemorrhoid thin this is found in orthopods and molasks. So, for example, lobster, crayfish, arachnids all are having these short of copper center or di copper center for oxygen binding 3 histidine is bound with 1 copper another copper is having 3 another 3 histidine and the oxygen is getting reduced by 2 electron 1 electron each from each of these copper to form the iron peroxo species. You can see the distance between these 2 copper center was 4.6 angstrom it is reduced to 3.6 angstrom upon the oxygen binding. So, these are trigonal planar copper 1 center and these are super sensitive ok this can react with oxygen while almost immediately right. These are completely reversible oxygen binding and upon oxygen binding it forms the peroxo that means 2 electron reduced species which has a characteristics peak of oxygen-oxygen stress 750 wave number which once again just like what you have seen in hemorrhoid thin are peroxo, but it is a different type of peroxo. It is a side on peroxo in the hemorrhoid thin you have seen a hydro peroxo and in an almost an end on version right. So, therefore, these species are all different both hemoglobin hemorrhoid thin are different compared to hemocyanin, but one thing puts them in common box and that is they are capable of transporting oxygen. They do not utilize oxygen for any other activity other than transporting right. So, that makes them very interesting this species is colorless in nature this places is blue in nature in all these cases you have seen hemoglobin bead, hemoglobin hemorrhoid thin or hemocyanin all these cases oxygenated species are really bright color right. You have seen red, red and blue hemoglobin hemorrhoid thin and hemocyanin that makes it quite exciting. As you know there exist a number of mimic synthetic mimic that exactly kind of nowadays mimic what is happening in hemocyanin. The efforts for mimicking with a tetradentate ligand is this one we will discuss we have discussed this before with the bidentate mimic is this one, but the one which is found in hemocyanin is exactly this one which is found with this tridentate ligand backbone right which is fantastic and it matches exactly the spectroscopic features also both UV visible and resonance Raman. So, let therefore, let let me summarize by telling you that as you have seen hemoglobin myoglobin of course, hemoglobin myoglobin hemorrhoid thin and hemocyanin these are all great enzyme and they are all capable of binding oxygen in a reversible format and they are not interested in anything else. Nature has designed these in such a way so that there is no substrate available.  We will summarize that as well in another class, but if there is a substrate available in front of this it will end up reacting because all of these all of these intermediate in hemoglobin myoglobin hemocyanin hemorrhoid thin all of them are reactive intermediate. Since there is the design or architecture does not allow to have any organic substrate present in front of them therefore, they are sitting pretty and idle they are not going to do any chemistry they will be as if their hands are tied and they are very happy to just transport the oxygen and deliver it ok. So, that is that is all for today, but as you know these chemistry takes quite an interesting turn when you have cytochrome p450 or tyrosinase for example, for hemocyanin you see these chemistry becomes much more beautiful much more exciting in terms of substrate oxygenation chemistry or the synthetic chemistry we will come back to those in summarizing those in the next class. Thank you very much keep studying.