Purification of core enzyme of Escherichia coli RNA polymerase by affinity chromatography

A method for isolation of a highly purified preparation of E. coli RNA polymerase core enzyme was developed based on IMPACT technology and dissociation of the RNA polymerase complex with sigma(70) subunit. Washing of the immobilized RNA polymerase with 5-10 mM solution of glutamate (pH 5.0-5.5) completely removed the sigma(70) subunit from the holoenzyme and decreased amounts of protein admixtures. The possibility of reconstruction of the RNA polymerase holoenzyme directly on the affinity column was demonstrated. Activities of the resulting RNAP core enzyme preparations were tested by in vitro transcription. Some amino acids and their mixtures were shown to influence the in vitro transcription. The findings indicate that changes in the transcription efficiency in the presence of amino acids should be associated with a specific destruction of the interaction between sigma(70) subunit and the core enzyme.