DNA-dependent RNA polymerase of Escherichia coli induces bending or an increased flexibility of DNA by specific complex formation.

Escherichia coli RNA polymerase is shown to induce bending or an increased flexibility of the promoter DNA. This is a specific effect of holoenzyme (core enzyme and sigma-factor). The centre of the flexibility is 3 bp upstream of the initiation point of RNA synthesis. This flexibility or bending is maintained during RNA synthesis by core enzyme.