Family M5


Summary Holotypes Alignment Tree Genomes Literature

Summary for family M5

NamePeptidase family M5 (mycolysin family)
Family type peptidaseM05.001 - mycolysin (Streptomyces cacaoi), MEROPS Accession MER0001049 (peptidase unit: 206-550)
Content of familyPeptidase family M5 contains a metalloendopeptidase.
History Identifier created: Biochem.J. 290:205-218 (1993)
Family M5 contains only a peptidase from Streptomyces cacaoi. The gene was cloned and expressed in Streptomyces lividans, and the enzyme named mycolysin (Chang et al., 1990). No homologues are known from any other species, including the completely sequenced Streptomyces coelicolor genome.
Catalytic typeMetallo
Active site residuesH407 E408 H411 E445 
Active siteLike all peptidases in clan MA(E) mycolysin displays the HEXXH motif in which the histidines (His202 and His206) are zinc ligands and the electrophilic Glu203 is a catalytic residue; Glu240 is the third zinc ligand and is found within the Glu-(Xaa)3-Asp motif that is also found in thermolysin.
Activities and specificitiesMycolysin is synthesized with a 171-residue propeptide. It is most active in the range pH 5 - 7 (Chang et al., 1990; Chang & Lee, 1992).
InhibitorsLike most metallopeptidases, mycolysin is inhibited by EDTA.
Molecular structureThe tertiary structure of mycolysin has not been determined. The primary structure shows no significant similarity to that of any other metallopeptidase.
Basis of clan assignmentActive site residues for members of this family and thermolysin, the type example for clan MA, occur in the motif HEXXH
Distribution of family Bacteria details  
Archaea -  
Protozoa -  
Fungi -  
Plants -  
Animals -  
Viruses -  
Biological functionsMycolysin is activated by the autocatalytic cleavage of an AlaAla bond (Chang et al., 1992). It has an important role in bacterial nutrition.
Statistics for family M5Sequences:22
Identifiers with PDB entries:0
Downloadable files Sequence library (FastA format)
Sequence alignment (FastA format)
Phylogenetic tree (Newick format)
Peptidases and Homologues MEROPS ID Structure
family M5 non-peptidase homologuesnon-peptidase homologue-
family M05 unassigned peptidasesunassigned-