Chung W O, Demuth D R, Lamont R J
Department of Oral Biology, University of Washington, Seattle, Washington 98195, USA.
Infect Immun. 2000 Dec;68(12):6758-62. doi: 10.1128/IAI.68.12.6758-6762.2000.
Colonization of the plaque biofilm by the oral pathogen Porphyromonas gingivalis is favored by the presence of antecedent organisms such as Streptococcus gordonii. Coadhesion between P. gingivalis and S. gordonii can be mediated by the SspB protein of S. gordonii; however, the P. gingivalis cognate receptor for this protein has not been identified. In this study, we identified a surface protein of P. gingivalis that interacts with the SspB protein. Coprecipitation between P. gingivalis outer membrane proteins and purified SspB protein demonstrated that a 100-kDa P. gingivalis protein bound to SspB. The 100-kDa protein also bound to an engineered strain of Enterococcus faecalis that expresses the SspB protein on the cell surface. Monospecific polyclonal antibodies to the 100-kDa protein inhibited the binding between P. gingivalis and S. gordonii in a dose-dependent manner up to 86%. Amino acid sequencing of the 100-kDa protein showed homology to a protein previously identified as the P. gingivalis minor fimbria. The minor fimbrial protein may exist as a complex with a hemagglutinin-like protein since the genes encoding these proteins are adjacent on the chromosome and are cotranscribed. Thus, the P. gingivalis receptor for S. gordonii SspB is a 100-kDa protein that structurally may be a minor fimbria-protein complex and functionally effectuates coadhesion.
口腔病原体牙龈卟啉单胞菌在菌斑生物膜中的定植受到前期定植菌（如戈登链球菌）的促进。牙龈卟啉单胞菌与戈登链球菌之间的共黏附可由戈登链球菌的SspB蛋白介导；然而，该蛋白在牙龈卟啉单胞菌上的同源受体尚未确定。在本研究中，我们鉴定出了牙龈卟啉单胞菌的一种与SspB蛋白相互作用的表面蛋白。牙龈卟啉单胞菌外膜蛋白与纯化的SspB蛋白之间的共沉淀表明，一种100 kDa的牙龈卟啉单胞菌蛋白与SspB结合。该100 kDa蛋白还与在细胞表面表达SspB蛋白的工程粪肠球菌菌株结合。针对该100 kDa蛋白的单特异性多克隆抗体以剂量依赖的方式抑制牙龈卟啉单胞菌与戈登链球菌之间的结合，抑制率高达86%。对该100 kDa蛋白的氨基酸测序显示，它与先前鉴定为牙龈卟啉单胞菌小菌毛的一种蛋白具有同源性。小菌毛蛋白可能与一种血凝素样蛋白形成复合物存在，因为编码这些蛋白的基因在染色体上相邻且共转录。因此，牙龈卟啉单胞菌中戈登链球菌SspB的受体是一种100 kDa的蛋白，其结构上可能是一种小菌毛 - 蛋白复合物，功能上实现共黏附。
