Open AccessA Na + /H + antiporter gene of the moderately halophilic bacterium Halobacillus dabanensis D‐8 T : cloning and molecular characterization
Author(s) -
Yang Li Fu,
Jiang Ju Quan,
Zhao Bai Suo,
Zhang Bo,
Feng De Qin,
Lu Wei Dong,
Wang Lei,
Yang Su Sheng
Publication year - 2006
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2005.00055.x
Subject(s) - antiporter , complementation , escherichia coli , biology , halophile , molecular cloning , bacillus subtilis , microbiology and biotechnology , molecular mass , biochemistry , peptide sequence , bacteria , gene , membrane , enzyme , genetics , phenotype
A gene encoding a Na + /H + antiporter was cloned from a chromosomal DNA of Halobacillus dabanensis strain D‐8 T by functional complementation. Its presence enabled the antiporter‐deficient Escherichia coli strain KNabc to survive in the presence of 0.2 M NaCl or 5 mM LiCl. The gene was sequenced and designated as nhaH . The deduced amino‐acid sequence of NhaH consists of 403 residues with a calculated molecular mass of 43 481 Da, which was 54% identical and 76% similar to the NhaG Na + /H + antiporter of Bacillus subtilis . The hydropathy profile was characteristic of a membrane protein with 12 putative transmembrane domains. Everted membrane vesicles prepared from E. coli cells carrying nhaH exhibited Na + /H + as well as Li + /H + antiporter activity, which was pH‐dependent with highest activities at pH 8.5–9.0 and at pH 8.5, respectively. Moreover, nhaH confers upon E. coli KNabc cells the ability to grow under alkaline conditions.