Burman N, Bergström S, Restrepo B I, Barbour A G
Department of Microbiology, University of Umeå, Sweden.
Mol Microbiol. 1990 Oct;4(10):1715-26. doi: 10.1111/j.1365-2958.1990.tb00549.x.
The relapsing fever agent Borrelia hermsii avoids the host's immune response by the strategy of multiphasic antigenic variation. A given Borrelia cell can express one of a number of alleles for polymorphic outer-membrane proteins, known as Vmp proteins. The genes for the variant-specific Vmp proteins of serotypes 7 and 21 of B. hermsii strain HS1 were sequenced. The genes, which were designated vmp7 and vmp21, were obtained from populations of borreliae before and after a switch in serotypes from 7 to 21. The analysis showed that vmp7 and vmp21 are 77% identical in terms of their coding sequence. The deduced translation products of vmp7 and vmp21 are polypeptides of 369 (37.2 kD) and 364 amino acids (37.1 kD), respectively. Vmp7 and Vmp21 have sequence features of prokaryotic lipoproteins and are processed as such during expression in E. coli. The secondary structure predictions of the Vmp proteins reveals analogous structures to the VSG proteins of the African trypanosome.
回归热病原体赫氏疏螺旋体通过多相抗原变异策略逃避宿主的免疫反应。特定的赫氏疏螺旋体细胞能够表达多种多态性外膜蛋白等位基因中的一种，这些蛋白被称为Vmp蛋白。对赫氏疏螺旋体HS1菌株血清型7和21的变异特异性Vmp蛋白的基因进行了测序。这些基因被命名为vmp7和vmp21，是从血清型从7转换到21之前和之后的疏螺旋体群体中获得的。分析表明，vmp7和vmp21在编码序列方面有77%的同一性。vmp7和vmp21推导的翻译产物分别是由369个氨基酸（37.2 kD）和364个氨基酸（37.1 kD）组成的多肽。Vmp7和Vmp21具有原核脂蛋白的序列特征，并且在大肠杆菌中表达时会按此方式进行加工。Vmp蛋白的二级结构预测显示出与非洲锥虫VSG蛋白相似的结构。
