Family U62


Summary Holotypes Alignment Tree Genomes Structure Literature

Summary for family U62

Family type peptidaseU62.001 - microcin-processing peptidase 1 (Escherichia coli), MEROPS Accession MER0016222 (peptidase unit: 1-450)
Content of familyPeptidase family U62 contains microcin-processing peptidases.
History 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 typePeptidase of unknown catalytic type
Active siteNo 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 specificitiesMicrocin-processing peptidase 1 (U62.001) cleaves the bacteriocin microcin B17 precursor at Gly26Val27.
Molecular structureThe 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TM0727 protein from Thermotoga maritima (Rife et al., 2005) and the BT3649 protein from Bacteroides thetaiotaomicron (unpublished) have been solved.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.
Distribution of family Bacteria details  
Archaea details  
Protozoa -  
Fungi -  
Plants details  
Animals details  
Viruses -  
Biological functionsMicrocin B17 is synthesised as a 69-residue precursor and is converted to the pro-form by MccB17 synthetase. The last stage in MccB17 maturation is the removal of the 26-residue leader peptide. Allali et al. (2002) demonstrated that bacterial mutations in either microcin-processing peptidase 1 (mpp-1, U62.001) or microcin-processing peptidase 2 (mpp-2, U62.002) prevented the maturation of pro-MccB17. It has been proposed that mpp-1 and mpp-2 interact to form a proteolytically active complex (Allali et al., 2002).
Statistics for family U62Sequences:3316
Identifiers with PDB entries:3
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Peptidases and Homologues MEROPS ID Structure
microcin-processing peptidase 1U62.001Yes
microcin-processing peptidase 2U62.002-
BT3649-type peptidaseU62.003Yes
TM0727-type putative peptidaseU62.004Yes
family U62 unassigned peptidasesunassigned-