Sequon

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A sequon is a sequence of three consecutive amino acids in a protein that can serve as the attachment site to a polysaccharide (sugar) called an N-linked-Glycan. This is a polysaccharide linked to the protein via the nitrogen atom in the side chain of asparagine (Asn). A sequon is either Asn-X-Ser or Asn-X-Thr, where X is any amino acid except proline. The term appears to have been first used by Derek Marshall [1]. The textbook by Dwek et. al. states that "Occasionally, such as in the leukocyte surface protein (CD69), the amino acid sequence Asn-Xaa- Cys is an acceptable sequon for the addition of N-linked glycans" [2]

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.

[edit] References

  1. ^ Marshall, R. D. (1974). "The nature and metabolism of the carbohydrate-peptide linkages of glycoproteins". Biochem. Soc. Symp. 40, 17-26 40: 17–26. 
  2. ^ Brooks, Susan; Miriam Dwek, Udo Schumacher (2002). Functional and molecular glycobiology.. Oxford UK: BIOS Scientific. ISBN 1859960227.