Figure 6.
Structural representation of the FUT8 active site mutants depicting the effects on enzyme kinetics. Residues in the FUT8 acceptor-binding site (A) or donor site (B) were mutated to Ala, expressed, purified, and assayed for enzyme activity using the A2-Asn acceptor substrate (Table S3). C, kcat/Km values for each of the respective mutants are shown. In A and B, residues that led to enzyme inactivation when mutated to Ala are indicated by cyan stick representations. Residues that reduced activity are indicated by tan stick representation. The K541A mutation had a minor impact on kcat/Km and is indicated in green stick representation.