Abstract The conformations of peptides and proteins are often influenced by glycans O- linked to serine (Ser) or threonine (Thr).(2S, 4R)-4-Hydroxyproline (Hyp), together with L- proline (Pro), are interesting targets for O-glycosylation because they have a unique influence on peptide and protein conformation. In previous work we found that glycosylation of Hyp does not affect the N-terminal amide trans/cis ratios (K trans/cis) or the rates of ...