Abstract
CPx-ATPases related to heavy-metal transport are a new subgroup of P-type ATPase. Its existence in plant cell have hardly observed. In this study, we isolated CPx-ATPase gene relate to heavy metal transport from genome DNA of Oscillatoria brevis and characterized.
Sequence analysis of the CPx gene (Bxa1) showed that it consists of 1983bp ORF and eight transmembrane helix. It contains high conservative regions of phosphorylation site (DKTGTL), ATP binding site (GDGINDAP), phosphatase domain (TGES) and putative cation transduction channel (CPC). Instead of the CXXC motif that is present in the N terminal of most metal transport CPx-ATPase, Bxa1 contains histidine rich motifs. rQRT-PCR analysis shows Bxa1 mRNA was induced by both monovalent (Cu+, Ag+) and divalent (Zn2+, Cd2+) heavy metal ions. Experiments on heavy-metal tolerance in E. coli which recombinant Bxa1 demonstrated that Bxa1 conferred resistance to both monovalent and divalent heavy metals.
