Cloning of a cDNA encoding a putative metal-transporting P-type ATPase from Arabidopsis thaliana

Metal-transporting P-type ATPases were recently proposed to constitute a newly emerged sub-family of cation-transporting P-type ATPases, and are known to occur widely in prokaryotes and eukaryotes. However, no instance has been reported for higher plants. A cDNA clone encoding a metal-transporting P-type ATPase was thus searched for, if present, and was identified in Arabidopsis thaliana. The amino acid sequence, predicted from the determined nucleotide sequence for the cloned cDNA, shows all the critical features common to known metal-transporting P-type ATPases. This plant P-type ATPase has a typical metal-binding motif at its N-terminal portion. The newly isolated Arabidopsis gene, named PAA1, provides us with the first instance of putative metal-transporting P-type ATPases in higher plants. Some results of genomic analyses for this gene are also presented.