Sijbrandi Robert, Stork Michiel, Luirink Joen, Otto Ben R
Department of Molecular Microbiology, Faculty of Earth and Life Sciences, VU-University Amsterdam de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
Microbes Infect. 2008 Apr;10(5):514-21. doi: 10.1016/j.micinf.2008.01.015. Epub 2008 Feb 8.
The Gram-negative anaerobic bacterium B. fragilis is a member of the commensal flora of the human intestine, but is also frequently found in severe intra-abdominal infections. Several B. fragilis virulence factors have been implicated in the development of these infections. A B. fragilis protein of circa 60-kDa was identified as a putative plasminogen binding protein (Pbp). The corresponding gene was located, cloned, sequenced and the subcellular localization of the protein was investigated. Pbp was both determined in the outer membrane of B. fragilis and of E. coli that expressed the cloned protein. Protease accessibility studies showed that the protein is expressed at the cell surface. Importantly, we demonstrated that Pbp is sufficient and required for plasminogen binding to whole cells in both E. coli and B. fragilis. Pbp-like proteins were also detected in some other Bacteroides subspecies. The role of this potential B. fragilis virulence factor in pathogenicity is discussed.
革兰氏阴性厌氧菌脆弱拟杆菌是人类肠道共生菌群的成员，但也经常在严重的腹腔内感染中被发现。几种脆弱拟杆菌毒力因子与这些感染的发生有关。一种约60 kDa的脆弱拟杆菌蛋白被鉴定为假定的纤溶酶原结合蛋白（Pbp）。确定了相应基因的位置，进行克隆、测序，并研究了该蛋白的亚细胞定位。在表达克隆蛋白的脆弱拟杆菌和大肠杆菌的外膜中均检测到Pbp。蛋白酶可及性研究表明该蛋白在细胞表面表达。重要的是，我们证明了Pbp对于纤溶酶原结合大肠杆菌和脆弱拟杆菌中的全细胞而言既是充分的也是必需的。在其他一些拟杆菌亚种中也检测到了类似Pbp的蛋白。本文讨论了这种潜在的脆弱拟杆菌毒力因子在致病性中的作用。
