Understanding the substrate specificity of the heparan sulfate sulfotransferases by an integrated biosynthetic and crystallographic approach

► New chemoenzymatic synthesis provides an approach to obtain HS with specific properties. ► Structures of HS sulfotransferases provide atomic detail of HS substrate interactions. ► Mutant sulfotransferases are new tools in the chemoenzymatic synthesis approach. Heparan sulfates (HSs) have potential therapeutic value as anti-inflammatory and antimetastasis drugs, in addition to their current use as anticoagulants. Recent advances in chemoenzymatic synthesis of HS provide a way to conveniently produce homogenous HS with different biological properties. Crystal structures of sulfotransferases involved in this process are providing atomic detail of their substrate binding clefts and interactions with their HS substrates. In theory, the flexibility of this method can be increased by modifying the specificities of the sulfotransferases based on the structures, thereby producing a new array of products.