Department of Biological Sciences, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201, USA.
J Bacteriol. 2011 Oct;193(19):5322-7. doi: 10.1128/JB.05480-11. Epub 2011 Jul 22.
Cells of the gliding bacterium Flavobacterium johnsoniae move rapidly over surfaces. Transposon mutagenesis was used to identify sprE, which is involved in gliding. Mutations in sprE resulted in the formation of nonspreading colonies on agar. sprE mutant cells in wet mounts were almost completely deficient in attachment to and movement on glass, but a small percentage of cells exhibited slight movements, indicating that the motility machinery was not completely disrupted. SprE is a predicted lipoprotein with a tetratricopeptide repeat domain. SprE is similar in sequence to Porphyromonas gingivalis PorW, which is required for secretion of gingipain protease virulence factors. Disruption of F. johnsoniae sprE resulted in decreased extracellular chitinase activity and decreased secretion of the cell surface motility protein SprB. Reduced secretion of cell surface components of the gliding machinery, such as SprB, may account for the defects in gliding. Orthologs of sprE are found in many gliding and nongliding members of the phylum Bacteroidetes, suggesting that similar protein secretion systems are common among members of this large and diverse group of bacteria.
滑行细菌黄杆菌细胞在表面上快速移动。转座子诱变用于鉴定 sprE，它参与滑行。sprE 突变导致琼脂上形成非扩散菌落。在湿载玻片上，sprE 突变细胞在玻璃上的附着和运动几乎完全缺乏，但一小部分细胞表现出轻微的运动，表明运动机制没有完全被破坏。SprE 是一种预测的脂蛋白，具有四肽重复结构域。SprE 的序列与牙龈卟啉单胞菌 PorW 相似，PorW 是牙龈蛋白酶毒力因子分泌所必需的。F. johnsoniae sprE 的缺失导致细胞外几丁质酶活性降低和细胞表面运动蛋白 SprB 的分泌减少。滑行机械的细胞表面成分（如 SprB）的分泌减少可能是滑行缺陷的原因。sprE 的同源物存在于厚壁菌门的许多滑行和非滑行成员中，这表明类似的蛋白质分泌系统在这个庞大而多样化的细菌群体中很常见。
