Extended Data Fig. 6: Activity assays on CghA and its mutants to examine endo-to-exo stereospecificity conversion.

The in vitro analyses were performed using the substrate analogue 8 as the substrate. Detailed reaction conditions are described in Methods unless otherwise specified below. The reactions were monitored at 288 nm. N-Boc-L-tryptophan methyl ester was used as an internal standard (IS) throughout the study. See Methods for details. Peaks denoted by asterisks are impurities from the chemical synthesis of 8. a, HPLC profiles of the reaction mixtures containing 8 as a substrate and (i) buffer only as a background reaction; (ii) the wild-type CghA; (iii) the A242S mutant; (iv) the M257V mutant; (v) the V391L mutant; (vi) the A242S/M257V mutant; (vii) the A242S/M257V/V391L mutant; (viii) the authentic reference of 9; and (ix) the authentic reference of 10. b, HPLC profiles of the reaction mixtures containing 8 as a substrate and (i) buffer, as a background reaction; (ii) the wild-type CghA; (iii) the A242S/M257V/V391L mutant; (iv) the A242N/M257V/V391L mutant; (v) the authentic reference of 9; and (vi) the authentic reference of 10.