Summary for clan PE

History	MEROPS 9.8 (17 December 2012)
Description	Serine or threonine nucleophile; N-terminal nucleophile
Contents of clan	Clan PE contains self-processing peptidases.
Evidence	The protein fold of the type peptidase of the clan is not closely similar to those of peptidases in any other clan. Clan PE contains peptidases of mixed catalytic type, in which the nucleophile can be either serine or threonine.
Catalytic mechanism	The peptidase DmpA (P01.001) is an N-terminal nucleophile hydrolase, but is not homologous to those in clan PB (Fanuel et al., 1999). (See also family P1.)
Peptidase activity	(See family P1.)
Protein fold	The tertiary structure of aminopeptidase DmpA from Ochrobactrum anthropi has been determined (P01.001; Bompard-Gilles et al., 2000). Peptidases in clan PE have an internal duplication, and each repeat consists two layers, a layer of helices and a beta sheet. The catalytic serine or threonine is at the start of one of the strands in the C-terminal repeat.
Homologous non-peptidase families	Glutamate N-acetyltransferase 2 from Streptomyces clavuligerus and molybdenum cofactor-binding domain have related structures. The fold is similar to that of the Ntn-hydrolases in clan PB, but this is believed to be a result of convergent evolution (Cheng & Grishin, 2005).

Families

Family	Family Type Peptidase	Structure
P1	DmpA aminopeptidase (Ochrobactrum anthropi)	Yes
T5	ornithine acetyltransferase precursor (Saccharomyces cerevisiae)	Yes