Family S66
Summary for family S66
| Family type peptidase | S66.001 - murein tetrapeptidase LD-carboxypeptidase (Pseudomonas-type) (Pseudomonas aeruginosa), MEROPS Accession MER0016191 (peptidase unit: 15-307) |
| Content of family | Peptidase family S66 contains bacterial LD-carboxypeptidases. |
| History |
Identifier created: Merops 7.2 (14 October 2005)
Among the first descriptions of LD-carboxypeptidase (S66.002) was the study of Izaki & Strominger (1968) in which the enzyme was termed D-alanine carboxypeptidase II. The enzyme was purified by Ursinus et al. (1992), and the catalytic mechanism and structure were determined for the Pseudomonas enzyme (S66.001) by Korza & Bochtler (2005). |
| Catalytic type | Serine |
| Active site residues | S115 E217 H285 |
| Active site | There is a catalytic triad, Ser, His Glu (Korza & Bochtler, 2005: see the Alignment). Family S51 also has this triad, but has an unrelated fold. |
| Activities and specificities | The physiological substrates are tetrapeptide peptidoglycan fragments that contain an L-configured residue (lysine or meso-diaminopimelic acid) to which is attached a C-terminal D-alanine residue. It is the bond to the C-terminal D-Ala residue that is hydrolysed. |
| Inhibitors | Results of inhibition studies have been inconsistent (Templin & Holtje, 2004). LD-Carboxypeptidase is notably not inhibited by EDTA or penicillin, unlike some other peptidases with related activities. |
| Molecular structure | The structure of LD-carboxypeptidase from Pseudomonas aruginosa described by Korza & Bochtler (2005) shows an N-terminal sheet and a C-terminal barrel domain. At the interface of the two domains, the catalytic serine residue adopts a highly strained conformation reminiscent of the 'nucleophilic elbow' in alpha/beta-hydrolases (clan SC). |
| Clan | SS |
| Peptidases and Homologues |
MEROPS ID |
Structure |
| murein tetrapeptidase LD-carboxypeptidase (Pseudomonas-type) | S66.001 | Yes |
| murein tetrapeptidase LD-carboxypeptidase (Escherichia-type) | S66.002 | Yes |
| microcin C7 immunity protein | S66.003 | Yes |
| Family S66 non-peptidase homologues | non-peptidase homologue | - |
| Family S66 unassigned peptidases | unassigned | Yes |
