Ge Y, Charon N W
Department of Microbiology and Immunology, West Virginia University, Morgantown 26506-9177, USA.
J Bacteriol. 1997 Jan;179(2):552-6. doi: 10.1128/jb.179.2.552-556.1997.
Most investigators have assumed that the periplasmic flagella (PFs) of Borrelia burgdorferi are composed of only one flagellin protein. The PFs of most other spirochete species are complex: these PFs contain an outer sheath of FlaA proteins and a core filament of FlaB proteins. During an analysis of a chemotaxis gene cluster of B. burgdorferi 212, we were surprised to find a flaA gene homolog with a deduced polypeptide having 54 to 58% similarity to FlaA from other spirochetes. Like other FlaA proteins, B. burgdorferi FlaA has a conserved signal sequence at its N terminus. Based on reverse transcription-PCR and primer extension analysis, this flaA homolog and five chemotaxis genes constitute a motility-chemotaxis operon. Immunoblots using anti-FlaA serum from Treponema pallidum and a lysate of B. burgdorferi showed strong reactivity to a protein of 38.0 kDa, which is consistent with the expression of flaA in growing cells.
大多数研究人员认为，伯氏疏螺旋体的周质鞭毛（PFs）仅由一种鞭毛蛋白组成。大多数其他螺旋体物种的PFs很复杂：这些PFs包含FlaA蛋白的外层鞘和FlaB蛋白的核心丝。在对伯氏疏螺旋体212的趋化基因簇进行分析时，我们惊讶地发现一个flaA基因同源物，其推导的多肽与其他螺旋体的FlaA有54%至58%的相似性。与其他FlaA蛋白一样，伯氏疏螺旋体FlaA在其N端有一个保守的信号序列。基于逆转录PCR和引物延伸分析，这个flaA同源物和五个趋化基因构成一个运动-趋化操纵子。使用梅毒螺旋体抗FlaA血清和伯氏疏螺旋体裂解物进行的免疫印迹显示，与一种38.0 kDa的蛋白质有强烈反应，这与flaA在生长细胞中的表达一致。
