文献类型： 外文期刊

作者： Yang LiFu ¹ ; Zhang Bo ¹ ; Wang Lei ¹ ; Yang SuSheng ¹ ;

作者机构： 1.China Agr Univ, Coll Biol Sci, Dept Microbiol & Immunol, Beijing 100193, Peoples R China

2.China Agr Univ, Minist Agr, Key Lab Agromicrobial Resource & Applicat, Beijing 100193, Peoples R China

3.Chinese Acad Trop Agr Sci, Rubber Res Inst, Danzhou 571737, Hainan, Peoples R China

4.Chinese Acad Trop Agr Sci, Minist Agr, Key Lab Physiol Trop Crops, Danzhou 571737, Hainan, Peoples R China

关键词： pH sensing;salt resistance;cation binding/translocation

期刊名称：CHINESE SCIENCE BULLETIN （ 影响因子：1.649； 五年影响因子：1.738 ）

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收录情况： SCI

摘要： The Na+/H+ antiporter plays key roles in maintaining low cytoplasmic Na+ level and pH homeostasis, while little is known about the Carboxyl-terminal hydrophilic tails of prokaryotic antiporters. In our previous study, the first Na+/H+ antiporter gene nhaH from moderate halophiles was cloned from Halobacillus dabanensis D-8 by functional complementation. A topological model suggested that only nine amino acid residues ((395)PLIKKLGMI(403)) existed in the hydrophilic C-terminal domain of NhaH. The C-terminal truncated mutant of NhaH was constructed by PCR strategy and designated as nhaH Delta C. Salt tolerance experiment demonstrated that the deletion of hydrophilic C-terminal nine amino acid residues significantly inhibited the complementation ability of E. coli KNabc, in which three main Na+/H+ antiporters nhaA, nhaB and chaA were deleted. Everted membrane vesicles prepared from E. coli KNabc/nhaH Delta C decreased both Na+/H+ and Li+/H+ exchange activities of NhaH, and also resulted in an acidic shift of its pH profile for Na+, indicating a critical role of the short C-terminal domain of NhaH antiporter in alkali cation binding/translocation and pH sensing.