Figure 4.
Substrate selectivity of wild-type and mutant DEBS3. (A) Scheme illustrating a competition assay to determine extender unit selectivity of DEBS3. Asterisk indicates domain location of mutations. (B) Extracted ion chromatograms of DEBS3-catalyzed chain extension reactions (7 [M-H2O+H]+ m/z = 279.1955; 8 [M-H2O+H]+ m/z = 303.1955; 9 [M-H2O+H]+ m/z = 337.2366; 10 [M-H2O+H]+ m/z = 361.2373). See Experimental Section for a complete description of product identification and quantification. (C) Product distribution of DEBS3-catalyzed chain reactions (values are mean ± SD; n = 3).