Family M74
Summary for family M74
| Family type peptidase | M74.001 - murein endopeptidase (Escherichia coli), MEROPS Accession MER0001298 (peptidase unit: 20-274) |
| Content of family | Peptidase family M74 contains murein endopeptidase MepA. |
| History |
Identifier created: MEROPS 6.9 (16 December 2004)
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| Catalytic type | Metallo |
| Active site residues | H113 D120 H209 H211 |
| Active site | MepA (M74.001) is a metallopeptidase containing a single zinc ion bound by two histidines and an aspartate. The metal ligands occur in the motifs His-Xaa(6)-Asp and His-Xaa-His, which are characteristic of clan MD. His206 and His209 may be additional active site residues (Marcyjaniak et al., 2004). |
| Activities and specificities | MepA hydrolyses the Ala-D-Glu-meso-diaminopimelate D-Ala bond in the crosslinking peptide and the Ala-D-Glu-meso-diaminopimelatemeso-diaminopimelate-D-Glu-Ala bond between crosslinking peptides. The pH optimum is 6.0 and divalent cations (Ca2+, Mg2+, Co2+) are required for activity (Templin & Holtje, 2004). |
| Inhibitors | MepA is not inhibited by beta-lactam-derived antibiotics such as penicillin. DNA and polynucleotides are reported to be inhibitory (Templin & Holtje, 2004). |
| Molecular structure | The tertiary structure of MepA has been determined and is similar to that of D-Ala-D-Ala carboxypeptidases in family M15 (Marcyjaniak et al., 2004). Family M74 is therefore included in clan MD. |
| Clan | MD |
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Distribution of family
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Bacteria |
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Archaea |
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Protozoa |
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Fungi |
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Plants |
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Animals |
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Viruses |
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| Biological functions | There are many peptidases involved in the synthesis and lysis of bacterial cell walls, and murein endopeptidase MepA hydrolyses the murein crosslinks. Unlike the peptidases in clan SE, MepA is insensitive to penicillin. No other peptidase activities are known from the family, and MepA has only been characterized from Escherichia coli. MepA is a periplasmic protein synthesized with a signal peptide. The enzyme is not essential because mepA- mutants are viable. |
| Statistics for family M74 | Sequences: | 2295 |
| Identifiers: | 1 |
| Identifiers with PDB entries: | 1 |
| Downloadable files |
Sequence library (FastA format) |
| Sequence alignment (FastA format) |
| Phylogenetic tree (Newick format) |
