Positively regulates the expression of the NorB efflux pump and negatively regulates the expression of the AbcA efflux pump. Binds specifically to the promoters of norA, norB and norC and abcA genes. Overexpression of norG leads to an increase in the level of resistance to quinolones, associated with a threefold increase in norB transcripts. Disruption of norG leads to an increase in the level of resistance to methicillin, cefotaxime, penicillin G, and nafcillin, associated with a threefold increase in abcA transcripts. Could also have an aminotransferase activity. Down-regulated by MgrA. In the C-terminal section; belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.