Effect of proteolytic cleavage of surface-exposed proteins on infectivity of Chlamydia trachomatis
Effect of proteolytic cleavage of surface-exposed proteins on infectivity of Chlamydia trachomatis
复制标题
表面暴露蛋白的蛋白水解切割对沙眼衣原体感染性的影响
作者：
T. Hackstadt;H. Caldwell
沙眼衣原体 LGV-434 表面蛋白的蛋白水解裂解以及由此产生的对感染性和与培养的人上皮 (HeLa) 细胞关联的影响已被检查。在检测的几种蛋白酶中，胰蛋白酶、胰凝乳蛋白酶和嗜热菌蛋白酶可广泛裂解衣原体主要外膜蛋白 (MOMP)。胰蛋白酶和嗜热菌蛋白酶这两种蛋白酶将 MOMP 裂解到单特异性多克隆抗体免疫印迹无法检测到单体 MOMP 的程度。在嗜热菌蛋白酶的情况下，甚至没有检测到抗原片段。令人惊讶的是，对 HeLa 细胞的感染性并没有减弱。此外，本质上 14C 放射性标记的基本体 (EB) 与 HeLa 细胞的结合或蛋白酶 K 的解离并未受到 EB 先前胰蛋白酶处理的明显影响。乳过氧化物酶表面碘化基体的胰蛋白酶消化表明，大部分 125I 标记的表面蛋白被裂解。然而，在所有情况下，表面蛋白水解后，许多蛋白水解切割片段仍然与 EB 表面相关。当胰蛋白酶处理的 EB 在非还原条件下进行电泳并使用多克隆或类型特异性单克隆 MOMP 抗体进行免疫印迹时，发现 MOMP 呈大寡聚形式，无法进入聚丙烯酰胺堆积凝胶。此外，经胰蛋白酶处理的活 EB 与未经胰蛋白酶处理的对照生物体一样有效地结合放射性碘标记的类型特异性 MOMP 单克隆抗体。综上所述，研究结果表明，尽管 MOMP 对表面蛋白水解高度敏感，但 EB 表面蛋白质的超分子结构显然是通过二硫键相互作用维持的。因此，如果表面暴露的衣原体蛋白参与衣原体与真核细胞的初始相互作用，那么介导这种相互作用的这些蛋白的功能域必须能够抵抗蛋白水解并保持与EB表面的联系。
The proteolytic cleavage of Chlamydia trachomatis LGV-434 surface proteins and resultant effects on infectivity and association with cultured human epithelial (HeLa) cells have been examined. Of several proteases examined, trypsin, chymotrypsin, and thermolysin extensively cleaved the chlamydial major outer membrane protein (MOMP). Two proteases, trypsin and thermolysin, cleaved the MOMP to the extent that monomeric MOMP was not detectable by immunoblotting with monospecific polyclonal antibodies. In the case of thermolysin, not even antigenic fragments were detected. Surprisingly, infectivity toward HeLa cells was not diminished. In addition, the association of intrinsically 14C-radiolabeled elementary bodies (EBs) with HeLa cells or their dissociation by proteinase K was not measurably affected by prior trypsinization of the EBs. Trypsinization of lactoperoxidase surface-iodinated elementary bodies demonstrated that most of the 125I-labeled surface proteins were cleaved. In all cases, however, a number of proteolytic cleavage fragments remained associated with the EB surface after surface proteolysis. When trypsinized EBs were electrophoresed under nonreducing conditions and immunoblotted with either polyclonal or type-specific monoclonal MOMP antibodies, MOMP was found in a large oligomeric form that failed to enter the polyacrylamide stacking gel. Additionally, trypsinized viable EBs bound radioiodinated type-specific MOMP monoclonal antibody as efficiently as did the control nontrypsinized organisms. Taken together, the findings indicate that although the MOMP is highly susceptible to surface proteolysis, the supramolecular structure of the protein on the EB surface is apparently maintained by disulfide interactions. Thus, if surface-exposed chlamydial proteins are involved in the initial interaction of chlamydiae with eucaryotic cells, the functional domains of these proteins which mediate this interaction must be resistant to proteolysis and remain associated with the EB surface.
沙眼衣原体单克隆抗体：抗体特异性和抗原表征。
DOI：
--
发表时间：
1982
期刊：
Journal of immunology (Baltimore, Md. : 1950)
影响因子：
--
作者：
Stephens,RS;Tam,MR;Kuo,CC;Nowinski,RC
通讯作者：
Nowinski,RC
半胱氨酸二硫化物在白喉毒素跨膜转运中的功能作用。
DOI：
--
发表时间：
1984
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Wright,HT;Marston,AW;Goldstein,DJ
通讯作者：
Goldstein,DJ