N -Glycosylation
The N -Glykosylierung (synonym N glycosylation) is a post-translational modification , wherein the carbohydrates (glycosyl) to amino groups ( N -) of proteins are appended.
properties
The N -Glykosylierung is a form of glycosylation in which the glycosyl groups to the side chain of the amino acid asparagine (Asn) in proteins covalently to be connected. It occurs in all living things. The asparagine is in the recognition sequence (synonymous with the sequon ) Asn-X- Ser / Thr , with X for any amino acid except proline (Pro), serine (Ser) and threonine (Thr). Different N -glycosylations occur within a species , which among other things depend on the cell type . In contrast to N -glycosylation, in O -glycosylation the glycosyl group is transferred to the hydroxyl group of the side chain of the amino acids serine or threonine.
biosynthesis
The synthesis of the basic N- glycosylation structure takes place on dolichol pyrophosphate in the endoplasmic reticulum , the subsequent modification in the Golgi apparatus . The first carbohydrate on the amino group of a glycosylated asparagine is an N -acetylglucosamine (GlcNAc) in the β configuration . This is followed by another N -acetylglucosamine and three mannoses (Man) as the basic structure of the N -glycosylation, which is then followed by various modifications.
literature
- D. Voet, J. Voet: Biochemistry , 4th ed., Wiley, Weinheim 2011. ISBN 978-0-47057095-1 .
Individual evidence
- ^ A b c K. Drickamer, ME: Taylor Introduction to Glycobiology. 2nd edition. Oxford University Press, 2006. ISBN 978-0-19-928278-4 .