Purification and Characterization of RNA Polymerase from Fremyella diplosiphon

Abstract

A DNA-dependent RNA polymerase from the blue-green alga F. diplosiphone was purified and characterized. This enzyme, purified by gel filtration, DEAE-cellulose chromatography and glycerol gradient centrifugation, is comprised of 5 polypeptide subunits. Their masses are 161,000, 134,000, 91,000, 72,000 and 41,000 daltons. Preparative electrophoresis of the purified enzyme on nondenaturing gels separates the 41,000 dalton polypeptide from the rest of the enzyme. The enzyme is extremely labile in the presence of a variety of salts of strong acids and bases; the purification procedure was devised to avoid exposure to such compounds.