Cellulose synthases: new insights from crystallography and modeling

•A crystal structure and a modeled structure of cellulose synthases are examined.•We explore similarities/differences between bacterial and plant cellulose synthase.•Molecular mechanisms for known cellulose synthase missense mutations are proposed.•We predict specific residues putatively involved in glucan translocation in plants.

Detailed information about the structure and biochemical mechanisms of cellulose synthase (CelS) proteins remained elusive until a complex containing the catalytic subunit (BcsA) of CelS from Rhodobacter sphaeroides was crystalized. Additionally, a 3D structure of most of the cytosolic domain of a plant CelS (GhCESA1 from cotton, Gossypium hirsutum) was produced by computational modeling. This predicted structure contributes to our understanding of how plant CelS proteins may be similar and different as compared with BcsA. In this review, we highlight how these structures impact our understanding of the synthesis of cellulose and other extracellular polysaccharides. We show how the structures can be used to generate hypotheses for experiments testing mechanisms of glucan synthesis and translocation in plant CelS.