Three putative cation/proton antiporters from the soda lake alkaliphile Alkalimonas amylolytica N10 complement an alkali-sensitive Escherichia coli mutant.

ABSTRACT: Attempts to identify members of the antiporter complement of the alkali- and saline-adapted soda lake alkaliphile Alkalimonas amylolytica N10 have used screens of DNA libraries in antiporter-deficient Escherichia coli KNabc. Earlier screens used Na(+) or Li(+) for selection but only identified one NhaD-type antiporter whose properties were inconsistent with a robust role in pH homeostasis. Here, new screens using elevated pH for selection identified three other putative antiporter genes that conferred resistance to pH >or=8.5 as well as Na(+) resistance. The three predicted gene products were in the calcium/cation antiporter (CaCA), cation/proton antiporter-2 (CPA2) and cation/proton antiporter-1 (CPA1) families of membrane transporters, and were designated Aa-CaxA, Aa-KefB and Aa-NhaP res

SUBMITTER: Wei Y 

PROVIDER: S-EPMC2538799 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature