Frosch M, Müller A
Institut für Medizinische Mikrobiologie, Medizinische Hochschule Hannover, Germany.
Mol Microbiol. 1993 May;8(3):483-93. doi: 10.1111/j.1365-2958.1993.tb01592.x.
Within the capsule gene complex (cps) of Neisseria meningitidis two functional regions B and C are involved in surface translocation of the cytoplasmically synthesized capsular polysaccharide, which is a homopolymer of alpha-2,8 polyneuraminic acid. The region-C gene products share characteristics with transporter proteins of the ABC (ATP-binding cassette) superfamily of active transporters. For analysis of the role of region B in surface translocation of the capsular polysaccharide we purified the polysaccharides of region B- and region C-defective Escherichia coli clones by affinity chromatography. The molecular weights of the polysaccharides were determined by gel filtration and the polysaccharides were analysed for phospholipid substitution by polyacrylamide gel electrophoresis and immunoblotting. The results indicate that the full-size capsular polysaccharide with a phospholipid anchor is synthesized intracellularly and that lipid modification is a strong requirement for translocation of the polysaccharide to the cell surface. Proteins encoded by region B are involved in phospholipid substitution of the capsular polysaccharide. Nucleotide sequence analysis of region B revealed two open reading frames, which encode proteins with molecular masses of 45.1 and 48.7 kDa.
在脑膜炎奈瑟菌的荚膜基因复合体（cps）中，两个功能区域B和C参与了胞质合成的荚膜多糖的表面转运，该多糖是α-2,8聚神经氨酸的同聚物。区域C基因产物与主动转运蛋白的ABC（ATP结合盒）超家族的转运蛋白具有共同特征。为了分析区域B在荚膜多糖表面转运中的作用，我们通过亲和层析纯化了区域B和区域C缺陷型大肠杆菌克隆的多糖。通过凝胶过滤测定多糖的分子量，并通过聚丙烯酰胺凝胶电泳和免疫印迹分析多糖的磷脂取代情况。结果表明，具有磷脂锚定的全长荚膜多糖在细胞内合成，并且脂质修饰是多糖转运到细胞表面的强烈要求。区域B编码的蛋白质参与荚膜多糖的磷脂取代。区域B的核苷酸序列分析揭示了两个开放阅读框，它们编码分子量分别为45.1和48.7 kDa的蛋白质。
