VieB moderately inhibits VieS-C autophosphorylation. Purified GST-VieS-C or MBP-VieS-C D1018A was incubated with 32P-ATP-γ in the presence or absence of 5 μM VieB over time at 30°C. Samples were stopped at indicated time points with the addition of 2X-denaturing sample buffer and separated using a 10% SDS-Page gel. GST-VieS-C labeled with 32P were observed by radioautography (A,C) and quantified in (B,D).The radioautograph shown is a representative of three replicates. Error bars represent the SEM of three replicates.