Stenson Trevor H, Weiss Alison A
Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, Ohio 45267-0524, USA.
Infect Immun. 2002 May;70(5):2297-303. doi: 10.1128/IAI.70.5.2297-2303.2002.
The Dsb family of enzymes catalyzes disulfide bond formation in the gram-negative periplasm, which is required for folding and assembly of many secreted proteins. Pertussis toxin is arguably the most complex toxin known: it is assembled from six subunits encoded by five genes (for subunits S1 to S5), with 11 intramolecular disulfide bonds. To examine the role of the Dsb enzymes in assembly and secretion of pertussis toxin, we identified and mutated the Bordetella pertussis dsbA, dsbB, and dsbC homologues. Mutations in dsbA or dsbB resulted in decreased levels of S1 (the A subunit) and S2 (a B-subunit protein), demonstrating that DsbA and DsbB are required for toxin assembly. Mutations in dsbC did not impair assembly of periplasmic toxin but resulted in decreased toxin secretion, suggesting a defect in the formation of the Ptl secretion complex.
Dsb 酶家族催化革兰氏阴性菌周质中的二硫键形成，这是许多分泌蛋白折叠和组装所必需的。百日咳毒素可以说是已知最复杂的毒素：它由五个基因（编码亚基 S1 至 S5）编码的六个亚基组装而成，有 11 个分子内二硫键。为了研究 Dsb 酶在百日咳毒素组装和分泌中的作用，我们鉴定并突变了百日咳博德特氏菌的 dsbA、dsbB 和 dsbC 同源物。dsbA 或 dsbB 中的突变导致 S1（A 亚基）和 S2（一种 B 亚基蛋白）水平降低，表明 DsbA 和 DsbB 是毒素组装所必需的。dsbC 中的突变不会损害周质毒素的组装，但会导致毒素分泌减少，这表明 Ptl 分泌复合物的形成存在缺陷。
