Pasteurella multocida toxin (PMT) inhibits osteoblastic differentiation in mammals and birds. Its N-terminal region binds to target cells, while its C-terminal region, with a Trojan horse-like shape, carries the intracellularly active moiety. The latter consists of three distinct domains: C1 (Pfam:PF11647), C2 and C3. This entry represents the C-terminal catalytic domain C3, which has a Cys-His-Asp triad known to perform acyl-hydrolysis such as peptidase activity or an acyl-transfer reaction. This domain adopts a typical alpha-beta protein fold with seven beta-strands and eight helices. It is organised into two subdomains that form the the biologically active cleft space [1,2].

1: Crystal structures reveal a thiol protease-like catalytic triad in the C-terminal region of Pasteurella multocida toxin. Kitadokoro K, Kamitani S, Miyazawa M, Hanajima-Ozawa M, Fukui A, Miyake M, Horiguchi Y; Proc Natl Acad Sci U S A. 2007;104:5139-5144. PMID:17360394

2: The bacterial Ras/Rap1 site-specific endopeptidase RRSP cleaves Ras through an atypical mechanism to disrupt Ras-ERK signaling. Biancucci M, Minasov G, Banerjee A, Herrera A, Woida PJ, Kieffer MB, Bindu L, Abreu-Blanco M, Anderson WF, Gaponenko V, Stephen AG, Holderfield M, Satchell KJF; Sci Signal. 2018; [Epub ahead of print] PMID:30279169