Summary for clan SF
Clan type peptidase | S24.003 - UmuD protein (Escherichia coli), MEROPS Accession MER0000576 (peptidase unit: 25-139); PDB accession 1UMU |
History | Methods Enzymol. 244:461-486 (1994) |
Description | Serine nucleophile; catalytic residues in the order Ser, Lys (or His) in sequence |
Contents of clan | Clan SF contains endopeptidases, some of which are self-processing proteins. |
Evidence | Families S24 and S26 are united in the clan by their similar protein folds (see below) and the similar catalytic residues. |
Catalytic mechanism | Catalytic residues occur in the order Ser, Lys or His (see the Alignment). The catalytic mechanism has been discussed by Paetzel et al. (2002). |
Peptidase activity | In many cases, specificity favours an alanine P1 residue. (See also families S24 and S26.) |
Protein fold | Tertiary structures have been determined for members of families S24 (repressor LexA, S24.001; Luo et al., 2001) and S26 (signal peptidase 1, S26.001; Paetzel et al., 1995). Peptidases in the clan are predominantly all-beta proteins, containing several coiled beta sheets and a beta barrel. Members of family S24 have an additional C-terminal domain containing a bundle of three helices presumably important for binding DNA. |
Homologous non-peptidase families | The fold is unique to the clan. |
Activation mechanism | The autolytic cleavage of LexA (S24.001) is promoted by formation of a complex that involves the protein RecA, or by alkaline conditions (Little, 1993). |
Other databases
| SCOP | 51306 |
Families
S24 |
repressor LexA (Escherichia coli) |
Yes |
S26 |
signal peptidase I (Escherichia coli) |
Yes |
Distribution of clan SF among Kingdoms of Organisms
S24 | - | - | - | - | - | - | - |
S26 | - | - | - | - | - | - | - |
Clan | - | - | - | - | - | - | - |