This family includes zinc amidases that have N-acetylmuramoyl-L-alanine amidase activity EC:3.5.1.28. This enzyme domain cleaves the amide bond between N-acetylmuramoyl and L-amino acids in bacterial cell walls (preferentially: D-lactyl-L-Ala). The ...
This family includes zinc amidases that have N-acetylmuramoyl-L-alanine amidase activity EC:3.5.1.28. This enzyme domain cleaves the amide bond between N-acetylmuramoyl and L-amino acids in bacterial cell walls (preferentially: D-lactyl-L-Ala). The structure is known for the bacteriophage T7 structure and shows that two of the conserved histidines are zinc binding.
T7 lysosome is a bifunctional protein found only in T7 phage. It has amidase activity in cleaving the amide bond between N-acetyl-muramic acid and L-alanine in the bacterial cell wall. It also acts as an inhibitor of T7 RNA polymerase, which provides a feedback mechanism that shuts off late transcription during infection and stimulates DNA replication. T7 lysosyme differs from the previously well-studied egg-white and phage T4 lysosymes not only in having an interaction with T7 RNA polymerase but also in the chemistry of lysis: it cuts the amide bond between N-acetylmuramic acid and L-alanine rather than the glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine in the peptidoglycan layer of bacterial cell walls.
Defined by 5 residues: HIS:A-13 [auth A-17]TYR:A-42 [auth A-46]HIS:A-118 [auth A-122]LYS:A-124 [auth A-128]CYS:A-126 [auth A-130]