|Family type peptidase||M99.001 - Csd4 peptidase (Helicobacter pylori) (Helicobacter pylori), MEROPS Accession MER0032094 (peptidase unit: 22-267)|
|Content of family||Family M99 contains bacterial cell wall-degrading carboxypeptidases|
Identifier created: MEROPS 10.0 (14 Mar 2016)|
Helicobacter pylori is a causative agent for peptic ulcers and gastric cancer. In order to survive in the stomach, the bacterium must colonize the gastric muucosa; colonization depends on motility, and this in turn depends upon the shape of the bacterium. A helically-shaped bacterium is more virulent (Sycuro et al., 2012). The bacterial shape is affected by reducing the number of cross-links or by trimming of the peptidoglycan muropeptides. The Csd4 protein (M99.001) is a zinc-dependent D,L-carboxypeptidase that cleaves a specific bond in a non-cross-linked muramyltripeptide, which in turn affects the cell shape (Kim et al., 2014).
|Active site residues||R86 E222 |
|Activities and specificities||The Csd4 peptidase cleaves the bond between the gamma-D-Glu+mDAP bond of the non-cross-linked murayltripeptide muramyl-Ala-gamma-D-Glu-mDAP. The carboxypeptidase recognizes its substrate by interacting with the mDAP moiety and undergoes a significant structural change when mDAP is bound (Kim et al., 2014).|
|Molecular structure||The tertiary structure has been determined and and Csd4 protein consists of three domains, an N-terminal carboxypeptidase domain, a central beta-barrel domain, and a C-terminal immunoglobulin-like domain (Kim et al., 2014). The carboxypeptidase domain is structurally similar to that of carboxypeptidases in family M14, hence family M99 is included in clan MC.|