Building mutational bridges between carbohydrate-active enzymes

The commercial value of specialty carbohydrates and glycosylated compounds has sparked considerable interest in the synthetic potential of carbohydrate-active enzymes (CAZymes). Protein engineering methods have proven to be highly successful in expanding the range of glycosylation reactions that these enzymes can perform efficiently and cost-effectively. The past few years have witnessed meaningful progress in this area, largely due to a sharper focus on the understanding of structure–function relationships and mechanistic intricacies. Here, we summarize recent studies that demonstrate how protein engineers have become much better at traversing the fitness landscape of CAZymes through mutational bridges that connect the different activity types.