One Fold, Many Polysaccharides: Chitin Synthases in the Structural Diversity of GT2 Glycosyltransferases

Glycosyltransferases (GTs) are essential enzymes across all life domains, catalyzing the synthesis of oligosaccharides, polysaccharides, and glycoconjugates. The GT2 family is particularly critical, encompassing enzymes for abundant organic polymers like cellulose and chitin. The synthesis of chitin polymers is catalyzed by the integral membrane enzyme, chitin synthase, specializing in structural component formation in fungi, arthropods, and molluscs. The first three-dimensional structures of chitin synthase from Candida albicans, Phytophthora sojae, and Saccharomyces cerevisiae, confirm consistency with the GT2 family’s GT-A fold. These structures reveal a conserved homodimeric architecture and gating motifs that regulate access to the chitin translocation channel. Here, we review the structural and mechanistic features of chitin synthases within the broader context of the GT2 glycosyltransferase family.