IN-VITRO ASSEMBLY OF AN ANION-STIMULATED ATPASE FROM PEPTIDE-FRAGMENTS

The oxyanion-translocating ATPase encoded by the ars operon of plasmid R 773 confers resistance to anti-monials and arsenicals in Escherichia coli by extrusion of the oxyanions from the cells. The catalytic subunit, the ArsA protein, is an oxyanion-stimulated ATPase with two nucleotide binding consensus sequences, one in the N-terminal half and one in the C-terminal half of the protein. In this report subclones of the arsA gene were constructed to produce polypeptide fragments of the ArsA protein. By themselves none of the fragments exhibited anion-stimulated ATPase activity. Denaturation and renaturation of mixtures of N- and C-terminal polypeptides that between them comprised an entire ArsA protein resulted in active ATPase complexes.