Figure 4.

Properties of N-terminal deletion mutants. The four indicated forms of sigma 54 were transcribed using supercoiled glnAp2 template, 95 mM total Na⁺ and K⁺ at 37°C, and limited elongation substrates, with deviations as indicated. NtrC (lanes 9–12) refers to the addition of phosphorylated activator and ATP. Heparin challenge (lanes 5–12) refers to the addition of heparin prior to adding nucleotides. The amino acid changes associated with HRS456, Sal58, and ΔN are shown below the figure. The leucine patch is boxed.