FIG. 3.

Properties of promoter-deletion clones. The direction of transcription is indicated by arrows and the position of the first nucleotide in each transcript is given. The DNA present in each of the deleted clones is shown by the broad lines, with the deletion end point given in parentheses. The expression from each of the constructs is given as β-galactosidase activity (Miller units). MoCo⁺ indicates that the strain (RK4353) is able to synthesize functional molybdenum cofactor. MoCo⁻ indicates that the strain (NS3; moeB) is unable to synthesize functional molybdenum cofactor. Each plasmid was examined in both a MoCo⁺ strain (RK4353) and a MoCo⁻ strain (NS3; moeB). The bacteria were grown in LB medium at 37°C. Growth conditions and additions were as described in Materials and Methods.