Family C51
Summary for family C51
| Family type peptidase | C51.001 - D-alanyl-glycyl peptidase (staphylococcal phage phi11-type) (Staphylococcus aureus), MEROPS Accession MER0011132 (peptidase unit: 1-127) |
| Content of family | Family C51 contains endopeptidases that hydrolyse bacterial cell-wall crosslinking peptides. |
| History |
Identifier created: MEROPS 5.00 (20 April 2000)
There are a wide variety of peptidases that are capable of lysing bacterial cell walls, including the lytic enzymes of bacteriophages. Bacteriophages escape from the bacterial cell by use of lytic enzymes that are either amidases that disrupt the acetylmuramyl bonds or are peptidases that cleave the crosslinking peptide that links the murein chains. The lytic enzyme from bacteriophage phi11 is a bifunctional enzyme that possesses both amidase and peptidase activities. The peptidase domain is also known as the CHAP domain (Bateman & Rawlings, 2003). |
| Catalytic type | Cysteine |
| Active site residues | C32 H95 |
| Active site | We predict an active site dyad consisting of Cys32 and His95. Asp25 (or Gln31) and Asn113 may complete a papain-like active site tetrad (see the Alignment). |
| Activities and specificities | D-Ala-Gly peptidase (C51.001) from bacteriophage phi11 has been shown to cleave the crosslinking peptide of the host Staphylococcus aureus at the D-Ala Gly bond. Cleavage of similar bonds also releases surface proteins that are bound to the crosslinking peptides (Navarre et al., 1999). As an amidase, it acts as an N-acetylmuramyl-L-alanyl amidase. |
| Molecular structure | D-Ala-Gly peptidase has a two-domain structure, and mutational analysis has confirmed that the peptidase unit is in the N-terminal domain (Navarre et al., 1999). The C-terminal domain is an amidase, and is also present in lysostaphin (M23.004) from peptidase family M23 . No tertiary structures have been determined for any member of family C51, but the family is included in clan CA on the basis of our prediction of the active site residues. |
| Clan | CA |
| Basis of clan assignment | Protein fold of the peptidase unit for members of this family and resembles that of papain, the type example for clan CA. |
| Peptidases and Homologues |
MEROPS ID |
Structure |
| D-alanyl-glycyl peptidase (staphylococcal phage phi11-type) | C51.001 | - |
| bacteriophage B30 lysin | C51.002 | - |
| fused glutathionylspermidine amidase/glutathionylspermidine synthetase (Escherichia coli) | C51.A01 | Yes |
| Family C51 non-peptidase homologues | non-peptidase homologue | - |
| Family C51 unassigned peptidases | unassigned | - |
