Fig 2. Assessments of solvent tolerance and chelator challenge.
Potential complications of screening conditions were addressed by challenging ObgGC with various concentrations of DMSO (A) or multiple known chelators (B) followed by measurement of GTPase ObgGC activity using free phosphate quantitation with BIOMOL Green. Protein activity was similar in the presence of 0–5% DMSO and in the presence of three common chelators EDTA, EGTA, and NTA tested 40 μM final concentration. CA significantly decreased the amount of phosphate detected, but it also decreased the background phosphate in the reaction lacking ObgGC (not shown), and was therefore altering the absorbance of the reagent, not acting as a chelator. Asterisk denotes significant difference (ANOVA, P < 0.0001).