Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8588, Japan.
Proc Natl Acad Sci U S A. 2010 Jan 5;107(1):276-81. doi: 10.1073/pnas.0912010107. Epub 2009 Dec 4.
Porphyromonas gingivalis secretes strong proteases called gingipains that are implicated in periodontal pathogenesis. Protein secretion systems common to other Gram-negative bacteria are lacking in P. gingivalis, but several proteins, including PorT, have been linked to gingipain secretion. Comparative genome analysis and genetic experiments revealed 11 additional proteins involved in gingipain secretion. Six of these (PorK, PorL, PorM, PorN, PorW, and Sov) were similar in sequence to Flavobacterium johnsoniae gliding motility proteins, and two others (PorX and PorY) were putative two-component system regulatory proteins. Real-time RT-PCR analysis revealed that porK, porL, porM, porN, porP, porT, and sov were down-regulated in P. gingivalis porX and porY mutants. Disruption of the F. johnsoniae porT ortholog resulted in defects in motility, chitinase secretion, and translocation of a gliding motility protein, SprB adhesin, to the cell surface, providing a link between a unique protein translocation system and a motility apparatus in members of the Bacteroidetes phylum.
牙龈卟啉单胞菌分泌强蛋白酶，称为牙龈蛋白酶，与牙周病发病机制有关。其他革兰氏阴性菌共有的蛋白分泌系统在牙龈卟啉单胞菌中缺失，但已有几种蛋白，包括 PorT，与牙龈蛋白酶分泌有关。比较基因组分析和遗传实验揭示了 11 种额外的与牙龈蛋白酶分泌相关的蛋白。其中 6 种（PorK、PorL、PorM、PorN、PorW 和 Sov）与黄杆菌滑行运动蛋白在序列上相似，另外 2 种（PorX 和 PorY）是假定的双组分系统调节蛋白。实时 RT-PCR 分析显示，牙龈卟啉单胞菌 porX 和 porY 突变体中 porK、porL、porM、porN、porP、porT 和 sov 的表达下调。破坏黄杆菌 porT 直系同源物导致运动、几丁质酶分泌和滑行运动蛋白 SprB 黏附素向细胞表面易位缺陷，为独特的蛋白易位系统与拟杆菌门成员的运动装置之间提供了联系。
