Sayavedra-Soto L A, Powell G K, Evans H J, Morris R O
Laboratory for Nitrogen Fixation, Oregon State University, Corvallis 97331.
Proc Natl Acad Sci U S A. 1988 Nov;85(22):8395-9. doi: 10.1073/pnas.85.22.8395.
An indispensable part of the hydrogen-recycling system in Bradyrhizobium japonicum is the uptake hydrogenase, which is composed of 34.5- and 65.9-kDa subunits. The gene encoding the large subunit is located on a 5.9-kilobase fragment of the H2-uptake-complementing cosmid pHU52 [Zuber, M., Harker, A.R., Sultana, M.A. & Evans, H.J. (1986) Proc. Natl. Acad. Sci. USA 83, 7668-7672]. We have now determined that the structural genes for both subunits are present on this fragment. Two open reading frames are present that correspond in size and deduced amino acid sequence to the hydrogenase subunits, except that the small-subunit coding region contains a leader peptide of 46 amino acids. The two genes are separated by a 32-nucleotide intergenic region and likely constitute an operon. Comparison of the deduced amino acid sequences of the B. japonicum genes with those from Desulfovibrio gigas, Desulfovibrio baculatus, and Rhodobacter capsulatus indicates significant sequence identity.
日本慢生根瘤菌中氢循环系统不可或缺的一部分是摄取氢化酶，它由34.5 kDa和65.9 kDa的亚基组成。编码大亚基的基因位于H2摄取互补黏粒pHU52的一个5.9千碱基片段上[祖伯，M.，哈克，A.R.，苏尔塔纳，M.A. & 埃文斯，H.J.（1986年）《美国国家科学院院刊》83，7668 - 7672]。我们现已确定两个亚基的结构基因都存在于该片段上。存在两个开放阅读框，其大小和推导的氨基酸序列与氢化酶亚基相对应，只是小亚基编码区含有一个46个氨基酸的前导肽。这两个基因被一个32个核苷酸的基因间隔区隔开，可能构成一个操纵子。将日本慢生根瘤菌基因推导的氨基酸序列与来自巨大脱硫弧菌、杆状脱硫弧菌和荚膜红细菌的序列进行比较，结果显示出显著的序列同一性。
