Department of Microbiology, Nippon Dental University School of Life Dentistry at Tokyo, Tokyo, Japan.
FEMS Microbiol Lett. 2010 Jan;302(2):166-74. doi: 10.1111/j.1574-6968.2009.01848.x. Epub 2009 Nov 6.
Porphyromonas gingivalis transports Arg-gingipains and Lys-gingipain across the outer membrane via an unknown pathway. Recently, we found that the sov gene of P. gingivalis W83 was required for this step. In the present study, we characterized the Sov protein. We constructed a P. gingivalis strain that expresses histidine-tagged Sov instead of Sov. Subcellular fractionations and a histidine-tag pulldown experiment showed that histidine-tagged Sov was present in an outer membrane fraction. Furthermore, antiserum raised against the terminal regions of Sov obstructed the secretion of Arg-gingipains from wild-type W83 cells. A deletion study showed that the region from Phe2495 to the C-terminus Gln2499 of Sov is essential for gingipain secretion. Anti-histidine-tag immunoglobulins interfered with the secretion of Arg-gingipains by P. gingivalis cells that expressed histidine-tagged Sov. In conclusion, we found that Sov is an outer membrane protein participating in the secretion of gingipains and that the C-terminal region of Sov is exposed to the extracellular milieu and involved in the modulation of Sov function.
牙龈卟啉单胞菌通过未知途径将 Arg-牙龈蛋白酶和 Lys-牙龈蛋白酶转运穿过外膜。最近，我们发现牙龈卟啉单胞菌 W83 的 sov 基因是这一步骤所必需的。在本研究中，我们对 Sov 蛋白进行了表征。我们构建了一个表达组氨酸标记的 Sov 而不是 Sov 的牙龈卟啉单胞菌菌株。亚细胞分级分离和组氨酸标记下拉实验表明，组氨酸标记的 Sov 存在于外膜部分。此外，针对 Sov 末端区域的抗血清阻止了 Arg-牙龈蛋白酶从野生型 W83 细胞中的分泌。缺失研究表明，Sov 的苯丙氨酸 2495 到 Gln2499 末端的区域对于牙龈蛋白酶的分泌是必需的。抗组氨酸标记免疫球蛋白干扰了表达组氨酸标记的 Sov 的牙龈卟啉单胞菌细胞中 Arg-牙龈蛋白酶的分泌。总之，我们发现 Sov 是一种参与牙龈蛋白酶分泌的外膜蛋白，Sov 的 C 末端区域暴露于细胞外环境中，并参与 Sov 功能的调节。
