The catalytic triad for this family of proteases is HE-H-H, which in many members is in the sequence motif HEIGH.

1: Cloning and sequencing of two genes, prtA and prtB, from Myxococcus xanthus, encoding PrtA and PrtB proteases, both of which are required for the protease activity. Quillet L, Bensmail L, Barray S, Guespin-Michel J; Gene. 1997;198:135-140. PMID:9370274