Family M7

Family

Summary Holotypes Alignment Tree Genomes Structure Literature Architecture

Summary for family M7

Name	Peptidase family M7 (snapalysin family)
Family type peptidase	M07.001 - snapalysin (Streptomyces lividans), MEROPS Accession MER0001060 (peptidase unit: 43-227)
Content of family	Peptidase family M7 contains a metalloendopeptidase, snapalysin.
History	Identifier created: Biochem.J. 290:205-218 (1993)
Catalytic type	Metallo
Active site residues	H163 E164 H167 D173
Active site	Zinc is bound by two histidines and an aspartate in an HEXXHXXGXXD sequence motif; the glutamate is a catalytic residue. This motif is also found in family M6.
Activities and specificities	Snapalysin is active at neutral pH. The only known activity is cleavage of proteins of skimmed milk to form clear plaques around the growing bacterial colonies.
Inhibitors	Like many metalloenzymes, snapalysin is inhibited by 10 mM 1,10-phenanthroline (Butler, 2004).
Molecular structure	Snapalysin is one of the smallest peptidases known, with only 185 residues in its processed form. Most peptidases have a two domain structure with the active site between the domains, but the tertiary structure of snapalysin shows that its C-terminal domain is reduced to a single helix. The structure is similar to the N-terminal domain of thermolysin (M04.001), hence family M7 is included in clan MA. Because the zinc ligands are similarly spaced to those of astacin (M12.001), the family is included in subclan MA(M). In common with other members of subclan MA(M), there is a conserved methionine (in the "Met-turn") C-terminal to the active site motif. Snapalysin is unusual amongst peptidases of subclan MA(M) in not having a tyrosine residue conserved on the "Met-turn", nor a cysteine in the propeptide.
Clan	MA
Subclan	MA(D)
Basis of clan assignment	Protein fold of the peptidase unit for members of this family resembles that of thermolysin, the type example for clan MA.

Distribution of family	Bacteria	details
	Archaea	-
	Protozoa	-
	Fungi	-
	Plants	-
	Animals	-
	Viruses	-

Biological functions	Snapalysin is a secreted enzyme apparently without a signal peptide or a propeptide, even though N-terminal processing occurs. The endopeptidase is active with or without this processing (Butler, 2004).
Statistics for family M7	Sequences:	1251
	Identifiers:	1
	Identifiers with PDB entries:	1
Downloadable files	Sequence library (FastA format)
	Sequence alignment (FastA format)
	Phylogenetic tree (Newick format)

Other databases	CATH	3.40.390.10
	INTERPRO	IPR000013
	PFAM	PF02031
	SCOP	55487

Peptidases and Homologues	MEROPS ID	Structure
snapalysin	M07.001	Yes
Family M07 unassigned peptidases	unassigned	-