Nagano Keiji, Hasegawa Yoshiaki, Yoshida Yasuo, Yoshimura Fuminobu
Department of Microbiology, School of Dentistry, Aichi Gakuin University 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi, Japan.
PLoS One. 2017 Mar 15;12(3):e0173541. doi: 10.1371/journal.pone.0173541. eCollection 2017.
Porphyromonas gingivalis, a periodontopathic gram-negative anaerobic bacterium, generally expresses two types of fimbriae, FimA and Mfa1. However, a novel potential fimbrilin, PGN_1808, in P. gingivalis strain ATCC 33277 was recently identified by an in silico structural homology search. In this study, we experimentally examined whether the protein formed a fimbrial structure. Anion-exchange chromatography showed that the elution peak of the protein was not identical to those of the major fimbrilins of FimA and Mfa1, indicating that PGN_1808 is not a component of these fimbriae. Electrophoretic analyses showed that PGN_1808 formed a polymer, although it was detergent and heat labile compared to FimA and Mfa1. Transmission electron microscopy showed filamentous structures (2‒3 nm × 200‒400 nm) on the cell surfaces of a PGN_1808-overexpressing P. gingivalis mutant (deficient in both FimA and Mfa1 fimbriae) and in the PGN_1808 fraction. PGN_1808 was detected in 81 of 84 wild-type strains of P. gingivalis by western blotting, suggesting that the protein is generally present in P. gingivalis.
牙龈卟啉单胞菌是一种牙周病相关的革兰氏阴性厌氧菌，通常表达两种菌毛，即FimA和Mfa1。然而，最近通过计算机模拟结构同源性搜索在牙龈卟啉单胞菌ATCC 33277菌株中鉴定出一种新的潜在菌毛蛋白PGN_1808。在本研究中，我们通过实验检测了该蛋白是否形成菌毛结构。阴离子交换色谱显示，该蛋白的洗脱峰与FimA和Mfa1主要菌毛蛋白的洗脱峰不同，这表明PGN_1808不是这些菌毛的组成成分。电泳分析表明，PGN_1808形成了聚合物，尽管与FimA和Mfa1相比，它对去污剂和热不稳定。透射电子显微镜显示，在过表达PGN_1808的牙龈卟啉单胞菌突变体（缺乏FimA和Mfa1菌毛）的细胞表面以及PGN_1808组分中存在丝状结构（2-3nm×200-400nm）。通过蛋白质印迹法在84株牙龈卟啉单胞菌野生型菌株中的81株中检测到了PGN_1808，这表明该蛋白普遍存在于牙龈卟啉单胞菌中。
