NtrC

NtrC is the name of the protein necessary for the procaryotic regulon transcription factor sigma N (sigma 54) to form an open complex with RNA polymerase in order to activate glnA transcription. The open --> closed conformational change of the sigmaN-RNA polymerase complex around the glutamine synthetase gene promoter requires ATP and involves the 180 degree turn of the DNA so that the NtrC protein (bound to two -140 and -108 upstream enhancer regions) may interact directly with the promoter-bound sigma N-RNA polymerase complex.