Benoit Stéphane, Mehta Nalini, Wang Ge, Gatlin Michael, Maier Robert J
Department of Microbiology, 812 Biological Sciences Building, University of Georgia, Athens, GA 30602, USA.
Microb Pathog. 2004 Mar;36(3):153-7. doi: 10.1016/j.micpath.2003.11.001.
Helicobacter pylori possesses a membrane-bound, nickel containing, hydrogen uptake hydrogenase enzyme; its synthesis requires structural as well as accessory proteins, the latter needed for the complete maturation of the enzyme. Our lab previously characterized mutants in the accessory hyp genes, hypA, hypB, hypD and hypF that were all severely affected for hydrogenase activity, and in some cases (hypA and hypB mutants) also affected for urease activity. This finding prompted us to disrupt the two remaining unstudied hyp genes of H. pylori, hypC and hypE, in order to see if the same pleiotropic effect would be observed. In both mutants hydrogenase activity was abolished but urease activity remained unaffected. Addition of 5 microM nickel into the growth medium partially restored the hydrogenase activity in the hypE mutant and to a lesser extent in the hypC mutant. In addition, we also disrupted the genes HP0634 (referred as hydD in the H. pylori 26695 genome database) and HP0635 (whose function was unknown, referred to here as hydE) to address their possible roles in the hydrogenase synthesis/maturation process. In both cases, hydrogenase activities were abolished and addition of nickel could not restore the activity, suggesting that these proteins are involved in the hydrogenase synthesis process rather than in nickel mobilization/insertion steps.
幽门螺杆菌拥有一种膜结合的、含镍的吸氢氢化酶；其合成需要结构蛋白和辅助蛋白，后者是该酶完全成熟所必需的。我们实验室之前对辅助性hyp基因（hypA、hypB、hypD和hypF）中的突变体进行了表征，这些突变体的氢化酶活性均受到严重影响，在某些情况下（hypA和hypB突变体），脲酶活性也受到影响。这一发现促使我们破坏幽门螺杆菌中另外两个未研究的hyp基因hypC和hypE，以观察是否会观察到相同的多效性效应。在这两个突变体中，氢化酶活性均被消除，但脲酶活性未受影响。向生长培养基中添加5微摩尔镍可部分恢复hypE突变体中的氢化酶活性，在hypC突变体中的恢复程度较小。此外，我们还破坏了基因HP0634（在幽门螺杆菌26695基因组数据库中称为hydD）和HP0635（其功能未知，此处称为hydE），以研究它们在氢化酶合成/成熟过程中的可能作用。在这两种情况下，氢化酶活性均被消除，添加镍无法恢复活性，这表明这些蛋白质参与氢化酶合成过程，而不是镍的转运/插入步骤。
