|Family type peptidase||U62.001 - microcin-processing peptidase 1 (Escherichia coli), MEROPS Accession MER0016222 (peptidase unit: 1-450)|
|Content of family||Peptidase family U62 contains microcin-processing peptidases.|
Identifier created: MEROPS 5.8 (19 March 2002)|
Microcin B17 (MccB17) is a ribosomally synthesised peptide antibiotic produced by diverse strains of gram-negative bacteria carrying the pMccB17 plasmid. The effects of MccB17 on sensitive bacterial cells include the inhibition of replication, induction of the SOS response, and induction of double-stranded breaks in DNA by the trapping of DNA gyrase complexes, which ultimately leads to cell death (Allali et al., 2002).
|Catalytic type||Peptidase of unknown catalytic type|
|Active site||No residues representing a standard catalytic triad were present in the solvent accessible area detected in the crystal structure of the TM0727 protein from Thermotoga maritima (Rife et al., 2005), and metal ions were absent from the structure. Either the TM0727 protein is not a peptidase or its catalytic type is very unusual.|
|Activities and specificities||Microcin-processing peptidase 1 (U62.001) cleaves the bacteriocin microcin B17 precursor at Gly26Val27.|
|Molecular structure||The tertiary structures of the TM0727 protein from Thermotoga maritima (Rife et al., 2005) and the BT3649 protein from Bacteroides thetaiotaomicron (unpublished) have been solved. The TM0727 protein is a homodimer, and the fold of each monomer consists of two domains, the N-terminal domain containing two repeats showing two-fold pseudosymmetry, forming a long, antiparallel beta-sheet, whereas the C-terminal domain contains three sheets and five helices. In the dimer, a solvent accessible area, the most likely candidate for the active site, is buried. The fold is unlike that of any other protein.|