Aliabadi Z, Winkler H H, Wood D O
Department of Microbiology and Immunology, University of South Alabama College of Medicine, Mobile 36688.
Gene. 1993 Oct 29;133(1):135-40. doi: 10.1016/0378-1119(93)90238-x.
The gene (sdhA) coding for the flavoprotein subunit (SdhA) of succinate dehydrogenase of the obligate intracellular parasitic bacterium, Rickettsia prowazekii, has been isolated using an oligodeoxyribonucleotide probe to the conserved flavin adenine dinucleotide (FAD)-binding region of characterized flavoproteins. Nucleotide (nt) sequence analysis revealed an open reading frame (ORF) of 1791 bp capable of encoding a protein of 596 amino acids (aa) with a deduced M(r) of 65,444. The deduced aa sequence, when compared to the flavoprotein subunits of Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Bos taurus, revealed 52.8, 34.0, 65.8 and 52.0% aa identity, respectively. R. prowazekii SdhA produced in E. coli minicells and analyzed by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) migrated as a protein of approximately 63 kDa, comparable to the size of the deduced protein. In addition, two proteins of approximately 12 and 41 kDa were also produced in the E. coli minicells. The production of these proteins resulted from additional translational starts within the SdhA coding sequence, suggesting differences between the translational start signals of E. coli and R. prowazekii. Despite the similarity of R. prowazekii SdhA to that of E. coli, the R. prowazekii SdhA did not complement an E. coli sdhA mutant. In addition, analysis of the nt sequence immediately upstream from R. prowazekii sdhA revealed that the rickettsial sdh gene organization differs from that of E. coli and B. subtilis.
利用针对已鉴定黄素蛋白保守黄素腺嘌呤二核苷酸（FAD）结合区域的寡脱氧核糖核苷酸探针，分离出了专性细胞内寄生细菌普氏立克次体琥珀酸脱氢酶黄素蛋白亚基（SdhA）的编码基因（sdhA）。核苷酸（nt）序列分析揭示了一个1791 bp的开放阅读框（ORF），其能够编码一个由596个氨基酸（aa）组成的蛋白质，推导的分子量（M(r)）为65444。将推导的氨基酸序列与大肠杆菌、枯草芽孢杆菌、酿酒酵母和牛的黄素蛋白亚基进行比较，发现氨基酸同一性分别为52.8%、34.0%、65.8%和52.0%。在大肠杆菌小细胞中产生的普氏立克次体SdhA，经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析，迁移为一条约63 kDa的蛋白质条带，与推导蛋白质的大小相当。此外，在大肠杆菌小细胞中还产生了两条分别约为12 kDa和41 kDa的蛋白质条带。这些蛋白质的产生是由于SdhA编码序列内存在额外的翻译起始位点，这表明大肠杆菌和普氏立克次体的翻译起始信号存在差异。尽管普氏立克次体SdhA与大肠杆菌的SdhA有相似性，但普氏立克次体SdhA不能互补大肠杆菌的sdhA突变体。此外，对普氏立克次体sdhA上游紧邻的核苷酸序列分析表明，立克次体的sdh基因组织与大肠杆菌和枯草芽孢杆菌不同。
