What is one of the amino acids used in the biosynthesis of proteins, that is in a synthetic peptide consisting of eight amino acids?
3c886da19d2a4e957125f6f8edd74420
Strep-tag The Strep-tag® system is a method which allows the purification and detection of proteins by affinity chromatography. The Strep-tag II is a synthetic peptide consisting of eight amino acids (Trp-Ser-His-Pro-Gln-Phe-Glu-Lys). This peptide sequence exhibits intrinsic affinity towards Strep-Tactin®, a specifically engineered streptavidin and can be N- or C- terminally fused to recombinant proteins. By exploiting the highly specific interaction, "Strep"-tagged proteins can be isolated in one step from crude cell lysates. Because the "Strep"-tag elutes under gentle, physiological conditions it is especially suited for generation of functional proteins.
c5ff27513209a0e64c34cc3cfc5a7f22
Histidine Histidine (abbreviated as His or H; encoded by the codons CAU and CAC) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO form under biological conditions), and an imidazole side chain (which is partially protonated), classifying it as a positively charged amino acid at physiological pH. Initially thought essential only for infants, longer-term studies have shown it is essential for adults also.
a089c1bce72b26b6120b61c8af64eb9b
Peptide deformylase In enzymology, a peptide deformylase (EC 3.5.1.88 ) is an enzyme that catalyzes the chemical reaction
9a0625e829b4d589124ac4e657128982
Proteinoid Proteinoids, or thermal proteins, are protein-like, often cross-linked molecules formed abiotically from amino acids. Sidney W. Fox initially proposed that they may have been precursors to the first living cells (protocells). The term was also in the 1960s to describe peptides that are shorter than twenty amino acids found in hydrolysed protein, but this term is no longer commonly used.
c3488504f67abf2535d84eca71c2b43c
Bacteroid-trp RNA motif The Bacteroid-"trp" RNA motif is a conserved RNA element detected by bioinformatics. It is found in the phylum Bacteroidetes in the apparent 5' untranslated regions of genes that encode enzymes used in the synthesis of the amino acid tryptophan. A short open reading frame is found within the motif that encodes at least two tryptophan codons. Similar motifs have been identified regulating tryptophan genes in proteobacteria (see trp operon), but not in Bacteroidetes. However, the Bacteroid-"trp" RNA motif likely operates via the same machanism of attenuation.
dc8eb014ea1a7c8e0455ad9d3b69c561
Branched-chain amino acid A branched-chain amino acid (BCAA) is an amino acid having aliphatic side-chains with a branch (a central carbon atom bound to three or more carbon atoms). Among the proteinogenic amino acids, there are three BCAAs: leucine, isoleucine and valine. Non-proteinogenic BCAAs include 2-aminoisobutyric acid.
f1b4688bb111d3fcbbef7dc68b95f071
Synthetic antibody Synthetic antibodies are affinity reagents generated entirely in vitro, thus completely eliminating animals from the production process. Synthetic antibodies include recombinant antibodies, nucleic acid aptamers and non-immunoglobulin protein scaffolds. As a consequence of their in vitro manufacturing method the antigen recognition site of synthetic antibodies can be engineered to any desired target and may extend beyond the typical immune repertoire offered by natural antibodies. Synthetic antibodies are being developed for use in research, diagnostic and therapeutic applications. Synthetic antibodies can be used in all applications where traditional monoclonal or polyclonal antibodies are used and offer many inherent advantages over animal-derived antibodies, including comparatively low production costs, reagent reproducibility and increased affinity, specificity and stability across a range of experimental conditions.
8cfd69bf545a52d5807d1a98882a72f7
Pepsin Pepsin is an enzyme that breaks down proteins into smaller peptides (that is, a protease). It is produced in the stomach and is one of the main digestive enzymes in the digestive systems of humans and many other animals, where it helps digest the proteins in food. Pepsin has three dimensional structure, of which one or more polypeptide chains twist and fold, bringing together a small number of amino acids to form the active site, or the location on the enzyme where the substrate binds and the reaction takes place.
a9f31e7db2b4bcf5c8f5cbb48ee26a86
Polyhistidine-tag A polyhistidine-tag is an amino acid motif in proteins that consists of at least six histidine ("His") residues, often at the N- or C-terminus of the protein. It is also known as hexa histidine-tag, 6xHis-tag, His6 tag and by the trademarked name His-tag (registered by EMD Biosciences). The tag was invented by Roche, although the use of histidines and its vectors are distributed by Qiagen. Various purification kits for histidine-tagged proteins are available from Qiagen, Sigma, Thermo Scientific, GE Healthcare, Macherey-Nagel, Clontech, Bio-Rad, and others.
b56a0e8db82dd14397b7b8118f8a43d8
L-Photo-Leucine L-Photo-Leucine is a synthetic derivative of the L-Leucine amino acid that is used as its natural analog and is characterized for having photo-reactivity, which makes it suitable for observing and characterizing protein-protein interactions (PPI). When a protein containing this amino acid (A) is lightened with ultraviolet light while interacting with another protein (B), the complex formed from these two proteins (AB) remains attached and can be isolated for its study.
f41b384f950a435193004e6a17c1b8c5
4-Aminophenol 4-Aminophenol (or para"-aminophenol or p"-aminophenol) is the organic compound with the formula HNCHOH. Typically available as a white powder, it was commonly used as a developer for black-and-white film, marketed under the name Rodinal.
498064166ecb1d5e38875859625a2f4f
Glycosylamine Glycosylamines are a class of biochemical compounds consisting of a glycosyl group attached to an amino group, -NR. They are also known as N-glycosides, as they are a type of glycoside. Glycosyl groups can be derived from carbohydrates. The glycosyl group and amino group are connected with a β-N-glycosidic bond, forming a cyclic hemiaminal ether bond (α-aminoether).
5e67cd420697af9b92e9f9a3731e9a97
Synonymous substitution A synonymous substitution (often called a "silent" substitution though they are not always silent) is the evolutionary substitution of one base for another in an exon of a gene coding for a protein, such that the produced amino acid sequence is not modified. This is possible because the genetic code is "degenerate", meaning that some amino acids are coded for by more than one three-base-pair codon; since some of the codons for a given amino acid differ by just one base pair from others coding for the same amino acid, a mutation that replaces the "normal" base by one of the alternatives will result in incorporation of the same amino acid into the growing polypeptide chain when the gene is translated. Synonymous substitutions and mutations affecting noncoding DNA are often considered silent mutations; however, it is not always the case that the mutation is silent. Synonymous mutations can affect transcription, splicing, mRNA transport, and translation, any of which could alter phenotype, rendering the synonymous mutation non-silent. The substrate specificity of the tRNA to the rare codon can affect the timing of translation, and in turn the co-translational folding of the protein. This is reflected in the codon usage bias that is observed in many species. A nonsynonymous substitution results in a change in amino acid that may be arbitrarily further classified as conservative (change to an amino acid with similar physiochemical properties), semi-conservative (e.g. negative to positively charged amino acid), or radical (vastly different amino acid).
464e5eaf47909180654451b74213ebf7
Tripeptide A tripeptide is a peptide consisting of three amino acids joined by peptide bonds. The exact nature and function of proteins is determined by the amino acids present and the
b796beeae05e88f1f73afe2e70c36e57
Protein domain A protein domain is a conserved part of a given protein sequence and (tertiary) structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of several structural domains. One domain may appear in a variety of different proteins. Molecular evolution uses domains as building blocks and these may be recombined in different arrangements to create proteins with different functions. Domains vary in length from between about 25 amino acids up to 500 amino acids in length . The shortest domains such as zinc fingers are stabilized by metal ions or disulfide bridges. Domains often form functional units, such as the calcium-binding EF hand domain of calmodulin. Because they are independently stable, domains can be "swapped" by genetic engineering between one protein and another to make chimeric proteins.
bffbda1ffcda0940fdd8ebb92ec04d2b
Biomolecule A biomolecule or biological molecule is a loosely used term for molecules or more commonly ions that are present in organisms. Biomolecules including large macromolecules (or polyanions) such as proteins, carbohydrates, lipids, and nucleic acids, as well as small molecules such as primary metabolites, secondary metabolites, and natural products. A more general name for this class of material is biological materials. Biomolecules are usually endogenous but may also be exogenous. For example, pharmaceutical drugs may be natural products or semisynthetic (biopharmaceuticals) or they may be totally synthetic.
2f4263585506e0250b2214551371407a
Protein structure Protein structure is the three-dimensional arrangement of atoms in a protein molecule. Proteins are polymers — specifically polypeptides — formed from sequences of amino acids, the monomers of the polymer. A single amino acid monomer may also be called a residue indicating a repeating unit of a polymer. Proteins form by amino acids undergoing condensation reactions, in which the amino acids lose one water molecule per reaction in order to attach to one another with a peptide bond. By convention, a chain under 30 amino acids is often identified as a peptide, rather than a protein. To be able to perform their biological function, proteins fold into one or more specific spatial conformations driven by a number of non-covalent interactions such as hydrogen bonding, ionic interactions, Van der Waals forces, and hydrophobic packing. To understand the functions of proteins at a molecular level, it is often necessary to determine their three-dimensional structure. This is the topic of the scientific field of structural biology, which employs techniques such as X-ray crystallography, NMR spectroscopy, and dual polarisation interferometry to determine the structure of proteins.
a18e32bd77d7655dcc4eaad8eb1dfd39
Target peptide A target peptide is a short (3-70 amino acids long) peptide chain that directs the transport of a protein to a specific region in the cell, including the nucleus, mitochondria, endoplasmic reticulum (ER), chloroplast, apoplast, peroxisome and plasma membrane. Some target peptides are cleaved from the protein by signal peptidases after the proteins are transported.
4eca8680923e1031bd62098294f4c96d
Amino acid kinase In molecular biology, the amino acid kinase domain is a protein domain. It is found in protein kinases with various specificities, including the aspartate, glutamate and uridylate kinase families. In prokaryotes and plants the synthesis of the essential amino acids lysine and threonine is predominantly regulated by feed-back inhibition of aspartate kinase (AK) and dihydrodipicolinate synthase (DHPS). In "Escherichia coli", thrA, metLM, and lysC encode aspartokinase isozymes that show feedback inhibition by threonine, methionine, and lysine, respectively. The lysine-sensitive isoenzyme of aspartate kinase from spinach leaves has a subunit composition of 4 large and 4 small subunits.
20a115360cbd15786bc0f981fe27bd7b
Pi helix A pi helix (or π-helix) is a type of secondary structure found in proteins. Although once thought to be rare, short π-helices are found in 15% of known protein structures and are believed to be an evolutionary adaptation derived by the insertion of a single amino acid into an α-helix. Because such insertions are highly destabilizing, the formation of π-helices would tend to be selected against unless it provided some functional advantage to the protein. π-helices therefore are typically found near functional sites of proteins.
1db47edfa8b1434ed8b484610af5e1b0
Alpha-Aminobutyric acid α-Aminobutyric acid (AABA), also known as homoalanine in biochemistry, is a non-proteinogenic alpha amino acid with chemical formula CHNO. The straight two carbon side chain is one carbon longer than alanine, hence the prefix homo-.
3162b4919ae5545caba056ad93eac5f1
Apramycin Apramycin (also "Nebramycin II") is an aminoglycoside antibiotic used in veterinary medicine. It is produced by "Streptomyces tenebrarius".