Department of Urology, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto, Kumamoto 860-8556, Japan.
FEBS Lett. 2012 Oct 19;586(20):3613-7. doi: 10.1016/j.febslet.2012.08.004. Epub 2012 Aug 14.
ASP is a serine protease secreted by Aeromonas sobria, a sepsis-causing bacterium, and induces sepsis-mimicking disorders through plasma protein cleavage. The pathogen also secretes nASP that has a nick in the carboxy-terminal region. Compared with single-chain ASP (sASP), nASP had near-equivalent activity for small peptide substrates but was less proteolytic. Surprisingly, nASP cleaved proteins more in plasma and was inhibited by human α(2)-macroglobulin more slowly than sASP. Retarded inhibition by α(2)-macroglobulin allows nASP to keep proteolytic activity for longer in the host and exacerbate disorders at Aeromonas sobria infection sites. nASP may be an evolutional form to augment ASP virulence.
ASP 是气单胞菌分泌的一种丝氨酸蛋白酶，能通过切割血浆蛋白引发类似败血症的紊乱。该病原体还分泌带有羧基末端区域缺口的 nASP。与单链 ASP（sASP）相比，nASP 对半肽底物具有相近的活性，但蛋白水解活性较低。令人惊讶的是，nASP 对血浆中的蛋白质的切割作用更强，并且比 sASP 更能缓慢地被人α(2)-巨球蛋白抑制。α(2)-巨球蛋白的抑制作用被延迟，使 nASP 在宿主中保持更长时间的蛋白水解活性，并在气单胞菌感染部位加重紊乱。nASP 可能是一种增强 ASP 毒力的进化形式。
