9.B.355.1.1
The four component dentilisin cell surface protease complex of 400 kDa. The 4 protein constituents are PrtP, PrcA, PrcB, and Msp (Godovikova et al. 2011).  The major outer sheath protein (Msp or MOSP) has a bipartite domain architecture and exists as periplasmic and outer membrane-spanning conformers (Anand et al. 2013). The Msp complex depolarized and increased the conductance of the HeLa cell membrane in a manner which was not strongly selective for Na⁺, K⁺, Ca²⁺, and Cl^- ions. Cell-attached patches of HeLa cell membrane exposed to the Msp complex exhibited short-lived channels with a slope conductance of 0.4 nS in physiologically normal saline (Mathers et al. 1996). Pore-forming activities of recombinant Msp in black lipid model membrane assays and in HeLa cell membranes were similar to those reported for the native protein, supporting the hypothesis that Msp cytotoxicity is due to its pore-forming activity (Fenno et al. 1998). The oligomeric outer membrane-associated complex binds fibronectin and disrupts several intracellular responses.It may form a large-diameter β-barrel porin (Godovikova et al. 2019). The Msp protein is also listed with TC# 1.B.38.1.4.