Interaction of sigma(70) with Escherichia coli RNA polymerase core enzyme studied by surface plasmon resonance

The interaction between the core form of bacterial RNA polymerases and a fa ctors is essential for specific promoter recognition, and for coordinating the expression of different sets of genes in response to varying cellular n eeds. The interaction between Escherichia coli core RNA polymerase and sigm a(70) has been investigated by surface plasmon resonance. The His-tagged fo rm of sigma(70) factor was immobilised on a Ni2+-NTA chip for monitoring it s interaction with care polymerase, The binding constant for the interactio n was found to be 1.9 x 10(-7) M, and the dissociation rate constant for re lease of a from core, in the absence of DNA or transcription, was 4 x 10(-3 ) s(-1), corresponding to a half-life of about 200 s, (C) 2000 Federation o f European Biochemical Societies. Published by Elsevier Science B.V. All ri ghts reserved.