Analysis of the transcriptional unit encoding the genes for rubredoxin (rub) and a putative rubredoxin oxidoreductase (rbo) in Desulfovibrio vulgaris Hildenborough
Analysis of the transcriptional unit encoding the genes for rubredoxin (rub) and a putative rubredoxin oxidoreductase (rbo) in Desulfovibrio vulgaris Hildenborough
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希尔登伯勒脱硫弧菌中编码红氧还蛋白 (rub) 和假定的红氧还蛋白氧化还原酶 (rbo) 基因的转录单位的分析
作者：
M. Brumlik;G. Voordouw
编码来自普通脱硫弧菌 Hildenborough 的红氧还蛋白的基因（rub，162 个碱基对）上游的 2.0 千碱基对 EcoRI 限制片段的核苷酸序列表明，它是一个更大转录单元的一部分，包含一个额外的 378 碱基对开放阅读框，终止 rub 基因翻译起始处的 16 个核苷酸，并且可以编码 14 千道尔顿的多肽（kDa）。对从 D. vulgaris Hildenborough 和用质粒 pJK29 转化的大肠杆菌 TG2（其在 1.1 kDa 的 SalI 插入片段上含有这两个基因）分离的 RNA 进行 Northern (RNA) 印迹，证实了这种 14 kDa 多肽和红氧还蛋白的基因存在于 680 个核苷酸的单个转录本上。 14-kDa 多肽也是一种氧化还原蛋白的有力证据是，其 NH2 末端与脱硫氧还蛋白同源，脱硫氧还蛋白是从 D. gigas 中分离出来的一种小型二聚体氧化还原蛋白（每个单体 36 个氨基酸），协调两个铁原子。由于红氧还蛋白是 14-kDa 蛋白的潜在氧化还原伙伴，因此它暂时被命名为红氧还蛋白氧化还原酶，由 rbo 基因产生。 Southern 印迹表明 rbo-rub 操纵子存在于硫酸盐还原菌的多个物种和菌株中。
The nucleotide sequence of a 2.0-kilobase-pair EcoRI restriction fragment upstream from the gene (rub, 162 base pairs) encoding rubredoxin from Desulfovibrio vulgaris Hildenborough indicates that it is part of a larger transcriptional unit, containing an additional 378-base-pair open reading frame which terminates 16 nucleotides from the translational start of the rub gene and could encode a polypeptide of 14 kilodaltons (kDa). Northern (RNA) blotting of RNA isolated from both D. vulgaris Hildenborough and Escherichia coli TG2 transformed with plasmid pJK29, which contains both genes on a 1.1-kilobase-pair SalI insert, confirms that the genes for this 14-kDa polypeptide and rubredoxin are present on a single transcript of 680 nucleotides. Strong evidence that the 14-kDa polypeptide is also a redox protein is provided by the fact that its NH2 terminus is homologous to desulforedoxin, which has been isolated from D. gigas as a small dimeric redox protein (36 amino acids per monomer), coordinating two iron atoms. Since rubredoxin is a potential redox partner for the 14-kDa protein, it has been tentatively named rubredoxin oxidoreductase, produced by the rbo gene. Southern blotting indicates that the rbo-rub operon is present in several species and strains of sulfate-reducing bacteria.