InterPro domain: IPR019533

This entry represents a domain found in some members of the S26A family of serine endopeptidases. Peptidases S26A (signal peptidase I) removes the hydrophobic, N-terminal signal peptides as proteins are translocated across membranes. The type I signal peptidases are unique serine proteases that utilize a serine/lysine catalytic dyad mechanism in place of the classical serine/histidine/aspartic acid catalytic triad mechanism [ 1 ]. Peptidases S26B includes eukaryotic microsomal signal peptidases involved in the removal of signal peptides from secretory proteins as they pass into the endoplasmic reticulum lumen [ 2 ]. Peptidases 26C (TraF signal peptidase) are found in operons that encode elements of conjugative transfer systems.

1. Type I signal peptidases of Gram-positive bacteria. Biochim Biophys Acta 1694, 279-97
2. Families of serine peptidases. Meth. Enzymol. 244, 19-61