Figure EV2. Effect of Li⁺ and Cs⁺ on the kinetics of the NCD‐4 modification of the Burkholderia pseudomallei N‐type ATPase c‐ring.

100 μM NCD‐4 was added to the purified c‐ring in 1.0% DDM and MES buffer, pH 6.0. The trace shows the continuous increase of fluorescence upon NCD‐4 binding to Glu61 of the c‐ring.

1. Addition of 15 or 150 mM LiCl resulted in a drop in labeling efficiency to 55 or 17%.
2. Addition of 15 or 150 mM CsCl reduced the labeling efficiency to 44 or 24%, illustrating the effect of salt in the buffer 33 and the overall dilution of the reaction volume. Results of typical experiments are shown. Each experiment was repeated three times.