Family

SecE subunit of protein translocation complex (IPR005807)

Short name: SecE_bac

Family relationships

Description

Secretion across the inner membrane in some Gram-negative bacteria occurs via the preprotein translocase pathway. Proteins are produced in the cytoplasm as precursors, and require a chaperone subunit to direct them to the translocase component [PMID: 2202721]. From there, the mature proteins are either targeted to the outer membrane, or remain as periplasmic proteins. The translocase protein subunits are encoded on the bacterial chromosome.

The translocase itself comprises 7 proteins, including a chaperone protein (SecB), an ATPase (SecA), an integral membrane complex (SecCY, SecE and SecG), and two additional membrane proteins that promote the release of the mature peptide into the periplasm (SecD and SecF) [PMID: 2202721]. The chaperone protein SecB [PMID: 11336818] is a highly acidic homotetrameric protein that exists as a "dimer of dimers" in the bacterial cytoplasm. SecB maintains preproteins in an unfolded state after translation, and targets these to the peripheral membrane protein ATPase SecA for secretion [PMID: 10418149]. SecE, part of the main SecYEG translocase complex, is ~106 residues in length, and spans the inner membrane of the Gram-negative bacterial envelope. Together with SecY and SecG, SecE forms a multimeric channel through which preproteins are translocated, using both proton motive forces and ATP-driven secretion. The latter is mediated by SecA. The structure of the Escherichia coli SecYEG assembly revealed a sandwich of two membranes interacting through the extensive cytoplasmic domains [PMID: 12167867]. Each membrane is composed of dimers of SecYEG. The monomeric complex contains 15 transmembrane helices.

GO terms

Biological Process

GO:0009306 protein secretion

Molecular Function

GO:0015450 P-P-bond-hydrolysis-driven protein transmembrane transporter activity

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PRINTS
PANTHER
TIGRFAMs