Structural insights into polyisoprenyl-binding glycosyltransferases.

Glycosyltransferases (GTs) catalyze the addition of sugars to diverse substrates facilitating complex glycoconjugate biosynthesis across all domains of life. When embedded in or associated with the membrane, these enzymes often depend on polyisoprenyl-phosphate or -pyrophosphate (PP) lipid carriers, including undecaprenyl phosphate in bacteria and dolichol phosphate in eukaryotes, to transfer glycan moieties. GTs that bind PP substrates (PP-GTs) are functionally diverse but share some common structural features within their family or subfamily, particularly with respect to how they interact with their cognate PP ligands. Recent advances in single-particle cryo-electron microscopy (cryo-EM) have provided insight into the structures of PP-GTs and the modes by which they bind their PP ligands. Here, we explore the structural landscape of PP-GTs, focusing mainly on those for which there is molecular-level information on liganded states, and highlight how PP coordination modalities may be shared or differ among members of this diverse enzyme class.