Thiophosphate transfer from histidine kinases to response regulators. A) reaction with ATP32P showing phosphate transfer from the histidine kinase EnvZ to MBP-tagged OmpR. Lane 1: EnvZ, 2: MBP-OmpR alone, 3: MBP-OmpR + EnvZ [5 µM EnvZ, 5 µM MBP-OmpR]. B) reaction using ATPγS and the antibody assay showing thiophosphate transfer from the histidine kinase EnvZ to MBP-tagged OmpR. Lane 1: EnvZ, 2: MBP-OmpR alone, 3: MBP-OmpR + EnvZ [5 µM EnvZ, 5 µM MBP-OmpR]. C) thiophosphate transfer from the H-NOX associated histidine kinase in Hahella chejuensis to the response regulator found in the same predicted operon. Lane 1: Hahella histidine kinase, 2: Hahella response regulator alone, 3: Hahella histidine kinase + response regulator [20 µM Hahella histidine kinase, 5 µM Hahella response regulator].