Glikopeptid

Glikopeptidi su peptidi koji sadrže ugljeno hidratne grupe (glikane) kovalentno vezane za bočne lance aminokiselinskih ostataka peptida. Glikani na ćelijskoj površini (vezani za membranske proteine ili lipide) i oni vezani za glikoproteine imaju kritičnu ulogu u biologiji. Na primer ti konstrakti učestvuju u oplodnji,^[1] imunskom sistemu,^[2] moždanom razvoju,^[3] endokrinom sistemu^[3] i inflamaciji.^[3]^[4]

Glikopeptidne veze

N-vezani glikani

N-vezani glikani su vezani za ostatak asparagina (Asn, N). Oni su najzastupljeniji u prirodi. Mada većina N-vezanih glikana ima oblik GlcNAc-β-Asn,^[5] poznate su i druge manje zastupljene veze, kao što su GlcNac-α-Asn^[6] i Glc-Asn.^[7]

O-vezani glikani

O-vezani glikani se formiraju vezivanje aminokiselinske hidroksilne grupe iz bočnog lanca (serina ili treonina) sa glikanom. Većina O-vezanih glikana ima oblik GlcNac-β-Ser/Thr ili GalNac-α-Ser/Thr.^[5]

C-vezani glikani

Ot tri tipa veza najmanje zastupljeni i najmanje izučeni su C-vezani glikani. C-veza je kovalentana veza manoze i bočnog lanca triptofana. Primer C-vezanog glikana je α-manozil triptofan.^[8]

Reference

^ Talbot, P.; Shur, B. D.; Myles, D. G., Cell adhesion and fertilization: Steps in oocyte transport, sperm-zona pellucida interactions, and sperm-egg fusion. Biology of Reproduction 2003, 68, (1), 1-9.
^ Rudd, P. M.; Elliott, T.; Cresswell, P.; Wilson, I. A.; Dwek, R. A., Glycosylation and the immune system. Science 2001, 291, (5512), 2370-2376.
^ ^а ^б ^в Varki, A., Biological Roles of Oligosaccharides - All of the Theories Are Correct. Glycobiology 1993, 3, (2), 97-130.
^ Bertozzi, C. R.; Kiessling, L. L., Chemical glycobiology. Science 2001, 291, (5512), 2357-2364.
^ ^а ^б Vliegenthart, J. F. G.; Casset, F., Novel forms of protein glycosylation. Current Opinion in Structural Biology 1998, 8, (5), 565-571.
^ Shibata, S.; Takeda, T.; Natori, Y., The Structure of Nephritogenoside - a Nephritogenic Glycopeptide with Alpha-N-Glycosidic Linkage. Journal of Biological Chemistry 1988, 263, (25), 12483-12485.
^ Wieland, F.; Heitzer, R.; Schaefer, W., Asparaginylglucose - Novel Type of Carbohydrate Linkage. Proceedings of the National Academy of Sciences of the United States of America-Biological Sciences 1983, 80, (18), 5470-5474.
^ Debeer, T.; Vliegenthart, J. F. G.; Loffler, A.; Hofsteenge, J., The Hexopyranosyl Residue That Is C-Glycosidically Linked to the Side-Chain of Tryptophan-7 in Human Rnase U-S Is Alpha-Marmopyranose. Biochemistry 1995, 34, (37), 11785-11789.

Vidi još

[1] Talbot, P.; Shur, B. D.; Myles, D. G., Cell adhesion and fertilization: Steps in oocyte transport, sperm-zona pellucida interactions, and sperm-egg fusion. Biology of Reproduction 2003, 68, (1), 1-9.

[2] Rudd, P. M.; Elliott, T.; Cresswell, P.; Wilson, I. A.; Dwek, R. A., Glycosylation and the immune system. Science 2001, 291, (5512), 2370-2376.

[Varki-3] а ^б ^в Varki, A., Biological Roles of Oligosaccharides - All of the Theories Are Correct. Glycobiology 1993, 3, (2), 97-130.

[4] Bertozzi, C. R.; Kiessling, L. L., Chemical glycobiology. Science 2001, 291, (5512), 2357-2364.

[Vliegenthart,_J._F._G._1998-5] а ^б Vliegenthart, J. F. G.; Casset, F., Novel forms of protein glycosylation. Current Opinion in Structural Biology 1998, 8, (5), 565-571.

[6] Shibata, S.; Takeda, T.; Natori, Y., The Structure of Nephritogenoside - a Nephritogenic Glycopeptide with Alpha-N-Glycosidic Linkage. Journal of Biological Chemistry 1988, 263, (25), 12483-12485.

[7] Wieland, F.; Heitzer, R.; Schaefer, W., Asparaginylglucose - Novel Type of Carbohydrate Linkage. Proceedings of the National Academy of Sciences of the United States of America-Biological Sciences 1983, 80, (18), 5470-5474.

[8] Debeer, T.; Vliegenthart, J. F. G.; Loffler, A.; Hofsteenge, J., The Hexopyranosyl Residue That Is C-Glycosidically Linked to the Side-Chain of Tryptophan-7 in Human Rnase U-S Is Alpha-Marmopyranose. Biochemistry 1995, 34, (37), 11785-11789.

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