A novel NhaD-type Na+/H+ antiporter from the moderate halophile and alkaliphile Halomonas alkaliphila

作者：Wang, Yanhong; Song, Na; Yang, Lina; Abdel-Motaal, Heba; Zhang, Rui; Zhang, Zhenglai; Meng, Fankui; Jiang, Juquan^*

来源：Canadian Journal of Microbiology, 2017, 63(7): 596-607.

DOI：10.1139/cjm-2017-0104

• NhaD
• Na+/H+ antiporter
• pH-dependent activity profile
• moderate halophile and alkaliphile
• Halomonas alkaliphila

In this study, a NhaD-type Na+/H+ antiporter gene designated Ha-nhaD was obtained by selection of genomic DNA from the moderate halophile and alkaliphile Halomonas alkaliphila in Escherichia coli KNabc lacking 3 major Na+/H+ antiporters. The presence of Ha-NhaD conferred tolerance of E. coli KNabc to NaCl up to 0.6 mol.L-1 and to LiCl up to 0.2 mol.L-1 and to an alkaline pH. pH-dependent Na+(Li+)/H+ antiport activity was detected from everted membrane vesicles prepared from E. coli KNabc/pUC-nhaD but not those of KNabc/pUC18. Ha-NhaD exhibited Na+(Li+)/H+ antiport activity over a wide pH range from 7.0 to 9.5, with the highest activity at pH 9.0. Protein sequence alignment and phylogenetic analysis revealed that Ha-NhaD is significantly different from the 7 known NhaD-type Na+/H+ antiporters, including Dw-NhaD, Dl-NhaD, Vp-NhaD, Vc-NhaD, Aa-NhaD, He-NhaD, and Ha-NhaD1. Although Ha-NhaD showed a closer phylogenetic relationship with Ha-NhaD2, a significant difference in pH-dependent activity profile exists between Ha-NhaD and Ha-NhaD2. Taken together, Ha-nhaD encodes a novel pH-dependent NhaD-type Na+/H+ antiporter.

• 出版日期2017-7
• 单位东北农业大学; 黑龙江八一农垦大学