Cryo-EM density and atomic model for monogalactosyl serine (Ser-O-αGal). The monogalactosyl moiety is built in its pyranose conformation, which positions the hydroxyl group on carbon 6 such that it can hydrogen bond with the carbonyl group of the backbone of the PPII helix. Glycans associated with the neighboring hydroxyproline residues have been removed for clarity.
