Zinc-dependent activity of the cg0042 and cg2911 operon promoters. The promoter activities of the Zur-regulated operons cg0042 and cg2911 was measured in the wild-type strain C. glutamicum ATCC 13032 (WT) and in the zur mutant C. glutamicum JS2502 (zur) under low, high and zinc-chelated (TPEN) conditions. The relative expression of the gfp reporter gene was determined by real-time RT-PCR. The values are means of four measurements. The relative expression was calculated by using a C. glutamicum control carrying the empty expression vector pEPR1.