Hernando Y, Palacios J, Imperial J, Ruiz-Argüeso T
Departamento de Biotecnología, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Politécnica de Madrid, Spain.
FEMS Microbiol Lett. 1998 Dec 15;169(2):295-302. doi: 10.1111/j.1574-6968.1998.tb13332.x.
Rhizobium leguminosarum bv. viciae strain UPM791 induces in symbiosis with peas the synthesis of a nickel-containing hydrogenase which recycles the hydrogen evolved by nitrogenase. The genes required for synthesis of this hydrogenase, hupSLCDEFGHIJKhypABFCDEX, are clustered in the symbiotic plasmid. Analysis of a hypA-deficient mutant showed that HypA is essential for symbiotic hydrogenase activity and required for correct processing of the hydrogenase large subunit. Unlike other microoxically induced hyp genes, the hypA gene was only expressed in pea bacteroids from its own promoter. The hypA mRNA 5' end was mapped 109 bp upstream of the translational start codon. This distinct pattern of expression suggests a different role for HypA and the remaining Hyp proteins in hydrogenase synthesis.
豌豆根瘤菌蚕豆生物变种菌株UPM791与豌豆共生时会诱导合成一种含镍氢化酶，该酶可回收固氮酶产生的氢气。合成这种氢化酶所需的基因，即hupSLCDEFGHIJKhypABFCDEX，聚集在共生质粒中。对一个hypA缺陷型突变体的分析表明，HypA对于共生氢化酶活性至关重要，并且是氢化酶大亚基正确加工所必需的。与其他微氧诱导的hyp基因不同，hypA基因仅在豌豆类菌体中从其自身启动子开始表达。hypA mRNA的5'端位于翻译起始密码子上游109 bp处。这种独特的表达模式表明HypA与其余Hyp蛋白在氢化酶合成中具有不同的作用。
