The mechanism of replication of XVII. Purification and partial characterization of the gene A and A* proteins

Abstract

A simple method for purifying the gene A plus A* proteins of bacteriophage [Formula: see text] is presented. The proteins are relatively hydrophobic and precipitate from aqueous solutions at low ionic strength. The gene A plus A* protein preparation was able to stimulate [Formula: see text] DNA replication in vitro and was able to nick supercoiled [Formula: see text] replicative form I to produce unit-length linear and circular strands of DNA. The kinetics of the nicking reaction were more consistent with a stoichiometric than with a catalytic mechanism. Under nondenaturing conditions the presumably globular A and A* proteins sedimented with apparent molecular weights of 110 000 and 90 000.