Sequence pattern for the occurrence of N-glycosylation in proteins

To further understand the occurrence of N-glycosylation, 21 nonhomologous p roteins with Asn-x-Ser/Thr sequence were investigated. The results showed t hat some oligopeptides with Gly residues (G-x-y or y-x-G) are adjacent to t he N-glycosylated sequences. These oligopeptides are not only essential for the structure and function of the proteins, but they are also found to be often proteolytic processing sites. These properties suggest that these oli gopeptides may be a "sequence pattern" for the occurrence of N-glycosylatio n. The implications of the findings for protein structure and function are discussed.