This enzyme was  the first to have its crystal structure reported, which was done by David (*) Phillips, who also proposed a mechanism of this  enzyme that controversially had it proceed via an SN1 mechanism.
Mutants of this enzyme that have glutamine at the 35 position instead of glutamic acid have absolutely no catalytic  activity, and this enzyme shares many structural characteristics with lactalbumin. The molecule that occupies the D site of  this enzyme was shown to adopt an unusual conformation that stabilizes its oxonium ion intermediate. This enzyme was  the first to have its crystal structure reported, which was done by David (*) Phillips, who also proposed a mechanism of this  enzyme that controversially had it proceed via an SN1 mechanism. That proposed mechanism has been superseded by the Withers  mechanism, which agrees with the classification of this enzyme as a retaining glycosidase. For 10 points, name this enzyme that  catalyzes the hydrolysis of linkages between NAG and NAM residues in Gram- positive bacteria, and which is often obtained  from hen egg-whites, which gets its antibacterial properties from this enzyme.
Mutants of this enzyme that have glutamine at the 35 position instead of glutamic acid have absolutely no catalytic  activity, and this enzyme shares many structural characteristics with lactalbumin.
lysozyme [accept hen eggwhite lysozyme, because that’s the enzyme all the studies mentioned were done on]