Sequon

A sequon is a sequence of three consecutive amino acids in a proteinthat can serve as the attachment site to a polysaccharide (sugar) called an
N-linked-Glycan. This is a polysaccharidelinked to the protein via the nitrogen atom in the side chain ofasparagine (Asn). Asequon is either Asn-X-Ser or Asn-X-Thr, where X is any aminoacid except proline. The term appears to have been first used byDerek Marshall [cite journal
last = Marshall
first = R. D.
title = The nature and metabolism of the carbohydrate-peptide linkages of glycoproteins
journal = Biochem. Soc. Symp. 40, 17-26
volume = 40
pages = 17–26
date = 1974 ] .The textbook by Dwek et. al. states that "Occasionally, such as in the leukocyte surface protein (CD69), theamino acid sequence Asn-Xaa- Cys is an acceptable sequon for theaddition of N-linked glycans" [ cite book
last= Brooks
first= Susan
coauthors= Miriam Dwek, Udo Schumacher
title= Functional and molecular glycobiology.
year= 2002
publisher= BIOS Scientific
location= Oxford UK
isbn= 1859960227]

The term is not frequently used. For example it does not appear in the textbooks"Essentials of Glycobiology", edited by A. Varki or "Introduction to Glycobiology"by Maureen E. Taylor and Kurt Drickamer.

References