Sulfate activation from the R. meliloti cysteine regulon. (a) TLC plate analysis of several R. meliloti extracts for production of APS and PAPS. Lane 1 is a control reaction with no protein extract. The protein extracts were isolated from Rm1021 in M9 minimal medium (lane 2), JSS27 in M9 medium plus cysteine and methionine (lane 3), JSS27 in M9 medium plus cysteine (lane 4), JSS27 in M9 medium plus methionine (lane 5), JSS27 in M9 medium plus glutathione (lane 6), and MW26 in M9 medium plus methionine (lane 7). (b) Quantitation of the data from two experiments as in panel a.