Spectroscopic studies of Congo red binding to RNA polymerase

摘要: Abstract The azo dye Congo Red has a high affinity for nucleotide-binding enzymes. We have studied the binding of to RNA polymerase by circular dichroism (CD) and difference absorption spectroscopy, steady-state kinetics, nitrocellulose filter-binding. Induced CD shows that large number molecules bind holoenzyme. also demonstrates core enzyme at low ionic strengths distinctive site which is not present in holoenzyme, nor higher or pressece poly(dT). studies indicate can readily displace double-stranded polynucleotides (T7 DNA poly[d(A-T)]) from polymerase. Single-stranded (poly(dT) T7 open complexes) displaced except concentrations. Both kinetics filter-binding measurements support this conclusion. Difference spectra bound undergo stacking. postulate binds region with segment normally interacts, potent inhibitor because stacked polyanionic character.