Extracted ion chromatograms (EICs) of CgnA (magenta) and reactions of CgnA with CgnB and CgnE; CgnC; CgnB and CgnC; CgnC and CgnE; or CgnB, CgnC and CgnE (from top left to right). Addition of CgnC with cofactors to CgnA triggered the formation of a minor +16 Da species (green). Adding CgnA to CgnB, CgnE and CgnC with cofactors resulted in the consumption of CgnA (magenta) and the formation of a major product (+14 Da, blue) as well as minor products (+16 Da, green; +30 Da (a and b are peaks of the same mass, but with different retention times), orange). All EICs reflect the +5 charge state of CgnA (mutants) and products 0.01 Da. Representative experiments were repeated independently at least three times with similar results. Details can be found in Supplementary Fig. 5.
