The closed -> open conformational change of the sigma N-RNA polymerase complex around the glutamine synthetase gene promoter requires ATP and involves the formation of a loop between the enhancer and the promoter regions, which may be facilitated by DNA-bending proteins (such as IHF).
The transition from a closed to an open conformation of the sigma N-RNA polymerase complex around the glutamine synthetase gene promoter requires ATP and includes the formation of a loop between the enhancer and the promoter regions, which might be assisted by DNA-bending proteins (such as IHF).