Raulston J E, Davis C H, Schmiel D H, Morgan M W, Wyrick P B
Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill 27599-7290.
J Biol Chem. 1993 Nov 5;268(31):23139-47.
One route by which Chlamydia trachomatis is internalized into host endometrial epithelial cells is receptor-mediated endocytosis. Although this implies an adhesin-receptor interaction exists, specific chlamydial surface molecules have not been identified. We are investigating potential adhesin molecules using an in vitro functional assay to select for chlamydial recombinant Escherichia coli expressing an adherent phenotype. We have previously shown that E. coli JM109(pPBW58) attaches to epithelial cells by a specific process paralleling C. trachomatis and expresses at least three plasmid-encoded proteins (18, 28, and 82 kDa; Schmiel, D. H., Knight, S. T., Raulston, J. E., Choong, J., Davis, C. H., and Wyrick, P. B. (1991) Infect. Immun. 59, 4001-4012). In this report, we demonstrate that (i) the 82-kDa protein is associated with the outer membrane of both E. coli JM109-(pPBW58) and C. trachomatis serovar E elementary bodies; (ii) the plasmid-encoded protein is identical to the native chlamydial protein by mass, charge, antigenicity, and partial proteolytic peptide profiles; (iii) a highly homologous protein is present in C. trachomatis biovariant lymphogranuloma venereum; (iv) the 82-kDa protein is not covalently linked by disulfide bonds to other protein species in either E. coli JM109(pPBW58) or C. trachomatis; (v) sequence analysis of the open reading frame indicates this protein is a relative of the heat shock 70 family of proteins; and (vi) the inferred amino acid sequence contains a contiguous 73-amino acid region having 51% identity with the extracellular sperm receptor binding domain in Strongylocentrosus purpuratus (Foltz, K. R., Partin, J. S., and Lennarz, W. J. (1993) Science 259, 1421-1425). The potential involvement of an hsp70 protein in attachment may provide new insight on adherence mechanisms by obligate intracellular pathogens.
沙眼衣原体进入宿主子宫内膜上皮细胞的一条途径是受体介导的内吞作用。虽然这意味着存在黏附素 - 受体相互作用，但尚未鉴定出特定的衣原体表面分子。我们正在使用体外功能测定法研究潜在的黏附素分子，以筛选出表达黏附表型的衣原体重组大肠杆菌。我们之前已经表明，大肠杆菌JM109(pPBW58)通过与沙眼衣原体相似的特定过程附着于上皮细胞，并表达至少三种质粒编码的蛋白质（18、28和82 kDa；施密尔，D. H.，奈特，S. T.，劳尔斯顿，J. E.，钟，J.，戴维斯，C. H.，和怀里克，P. B.（1991年）。感染与免疫。59，4001 - 4012）。在本报告中，我们证明：（i）82 kDa的蛋白质与大肠杆菌JM109-(pPBW58)和沙眼衣原体血清型E原体的外膜相关；（ii）该质粒编码的蛋白质在质量、电荷、抗原性和部分蛋白水解肽谱方面与天然衣原体蛋白质相同；（iii）在沙眼衣原体生物变种性病性淋巴肉芽肿中存在一种高度同源的蛋白质；（iv）82 kDa的蛋白质在大肠杆菌JM109(pPBW58)或沙眼衣原体中均未通过二硫键与其他蛋白质种类共价连接；（v）开放阅读框的序列分析表明该蛋白质是热休克70家族蛋白质的一个亲属；（vi）推断的氨基酸序列包含一个连续的73个氨基酸区域，与紫球海胆中的细胞外精子受体结合域具有51%的同一性（福尔茨，K. R.，帕廷，J. S.，和伦纳兹，W. J.（1993年）。科学。259，1421 - 1425）。一种hsp70蛋白质在附着过程中的潜在参与可能为专性细胞内病原体的黏附机制提供新的见解。
