Summary for clan MM

Summary Structure Literature
HistoryMEROPS 5.00 (20 Apr 2000)
DescriptionWater nucleophile; water bound by single zinc ion ligated to two His (within the motif HEXXH) and Asp; membrane proteins with intramembrane active site.
Contents of clanClan MM contains the membrane-embedded metalloendopeptidases of family M50.
Evidence(See Protein fold.)
Catalytic mechanism(See family M50.)
Peptidase activity(See family M50.)
Protein foldThe tertiary structure has been determined for the MJ0392 protein (M50.006) from Methanocaldococcus jannaschii (Feng et al., 2007). Two of the metal ligands occur in an HEXXH motif, similar to that found in clan MA, and the third is an Asp. The active site is within one of the six transmembrane regions, and the fold is unlike that of thermolysin (M04.001), the type example for clan MA. Consequently, family M50 is placed in its own clan, MM.
EvolutionThe presence of homologues of clan MM in the genomes of bacteria, archaea and eukaryotes suggests that the clan is a very ancient one (Kinch & Grishin, 2005).
Activation mechanismThe activity of SpoIVFB (M50.002) is regulated by two other integral membrane proteins, SpoIVFA and BofA (Rudner & Losick, 2002).


Family Family Type Peptidase Structure
M50 site 2 peptidase (Homo sapiens) Yes

Distribution of clan MM among Kingdoms of Organisms