Summary for clan CL

Clan type peptidase	C60.002 - sortase B (Staphylococcus aureus), MEROPS Accession MER0020433 (peptidase unit: 5-242); PDB accession 1NG5_A
History	MEROPS 6.8 (20 August 2004)
Description	Cysteine nucleophile; catalytic residues in the order His, Cys in sequence
Contents of clan	Clan CL contains bacterial peptidases that hydrolase (and transfer) bacterial cell wall peptides.
Evidence	Structures are known to be similar for members of both families in the clan.
Catalytic mechanism	Peptidase (and transferase) activity is dependent upon a His, Cys catalytic dyad.
Peptidase activity	Peptidases in the clan act on substrates associated with bacterial cell wall cross-linking peptides, either cleaving the peptide itself (family C82) or cleaving proteins and forming new amide bonds betweent he new C-terminus and the cross-linking peptide (family C60).
Protein fold	Tertiary structures have been determined for sortase A (C60.001; Zong et al., 2004), sortase B (C60.002; Zong et al., 2004) and for a fragment of the L,D-transpeptidase of Enterococcus faecium (C82.001; Biarrotte-Sorin et al. (2006)). The protein fold consists of a closed beta barrel decorated on the outside with helices. The active site residues are at the end of the barrel.
Homologous non-peptidase families	The C-terminal domain from the ykuD transpeptidase of Bacillus subtilis has a similar fold (Bielnicki et al. (2006)).
Activation mechanism	Sortase A is activated by Ca²⁺ (Naik et al., 2005).
Other databases	SCOP	63817

Families

Family	Family Type Peptidase	Structure
C60	sortase A ({Staphylococcus}-type) (Staphylococcus aureus)	Yes
C82	L,D-transpeptidase ({Enterococcus}-type) (Enterococcus faecium)	Yes