Several phage-encoded peptidoglycan hydrolases have been found to share a conserved amidase domain with a variety of bacterial autolysins (N-acetylmuramoyl-L-alanine amidases), bacterial and eukaryotic glutathionylspermidine amidases, gamma-D-glutamyl-L-diamino acid endopeptidase and NLP/P60 family proteins. All these proteins contain conserved cysteine and histidine residues and hydrolyze gamma-glutamyl-containing substrates. These cysteine residues have been shown to be essential for activity of several of these amidases and their thiol groups apparently function as the nucleophiles in the catalytic mechanisms of all enzymes containing this domain. The CHAP (cysteine, histidine-dependent amidohydrolases/peptidases) superfamily includes a variety of previously uncharacterized proteins, including the tail assembly protein K of phage lambda. Some members of this superfamily are important surface antigens in pathogenic bacteria and might represent drug and/or vaccine targets.

中文翻译：

---

来自细菌和噬菌体自溶素的酰胺酶结构域定义了γ-D，L-谷氨酸特异性酰胺水解酶家族。

已发现几种噬菌体编码的肽聚糖水解酶与多种细菌自溶素（N-乙酰基村酰胺基-L-丙氨酸酰胺酶），细菌和真核谷胱甘肽亚精胺酰胺酶，γ-D-谷氨酰基-L-二氨基酸内肽酶共享一个保守的酰胺酶域NLP / P60家族蛋白。所有这些蛋白质均含有保守的半胱氨酸和组氨酸残基，并水解含γ-谷氨酰胺的底物。已经证明这些半胱氨酸残基对于这些酰胺酶中的几种的活性是必不可少的，并且它们的硫醇基显然在包含该结构域的所有酶的催化机理中起亲核试剂的作用。CHAP（半胱氨酸，组氨酸依赖性酰胺水解酶/肽酶）超家族包括多种先前未表征的蛋白质，包括噬菌体λ的尾部组装蛋白K。