Glycobiology

Defined in the broadest sense, glycobiology is the study of the structure, biosynthesis, and biology of saccharides (sugar chains or glycans) that are widely distributed in nature.cite book | author=Varki A, Cummings R, Esko J, Freeze H, Hart G, Marth J | book=Essentials of glycobiology | title=Essentials of glycobiology | publisher=Cold Spring Harbor Laboratory Press | year=1999 | ISBN=0-87969-560-9 |url=http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=glyco.TOC&depth=2] Sugars or saccharides are essential components of all living things and aspects of the various different roles they play in biology are researched in various different medical, biochemical and biotechnological fields.

History

The specific term glycobiology was coined in 1988 to recognize the coming together of the traditional disciplines of carbohydrate chemistry and biochemistry.cite journal | author=Rademacher TW, Parekh RB and Dwek RA. | title=Glycobiology| journal=Annu. Rev. Biochem. | year=1988 | pages=785–838 | volume=57 | pmid=3052290 | doi=10.1146/annurev.bi.57.070188.004033] This coming together was as a result of a much greater understanding of the cellular and molecular biology of glycans. However as early as the late nineteenth century pioneering efforts were being made by Emil Fisher to establish the structure of some basic sugar molecules.

Glycoconjugates

Sugars may be linked to other types of biological molecule to form glycoconjugates. Glycoproteins, proteoglycans and glycolipids are the most abundant glycoconjugates found in mammalian cells. They are found predominantly on the outer cell wall and in secreted fluids. Glycoconjugates have been shown to be important in cell-cell interactions due to the presence on the cell surface of various glycan binding receptors in addition to the glycoconjugates themselves.cite journal | author=Ma BY, Mikolajczak SA, Yoshida T, Yoshida R, Kelvin DJ, Ochi A | title= CD28 T cell costimulatory receptor function is negatively regulated by N-linked carbohydrates | journal=Biochem. Biophys. Res. Commun. | year=2004 | pages=60–7 | volume=317 | issue=1 | pmid=15047148 | doi=10.1016/j.bbrc.2004.03.012] cite journal | author=Takahashi M, Tsuda T, Ikeda Y, Honke K, Taniguchi N | title= Role of N-glycans in growth factor signaling | journal= Glycoconj. J. | year=2004 | pages=207–12 | volume=20 | issue=3 | pmid=15090734 | doi= 10.1023/B:GLYC.0000024252.63695.5c]

Glycomics

"Glycomics, analogous to genomics and proteomics, is the systematic study of all glycan structures of a given cell type or organism" and is a subset of glycobiology. [ [http://www.cshlpress.com/default.tpl?action=full&--eqskudatarq=666 Cold Spring Harbor Laboratory Press] Essentials of Glycobiology, Second Edition]

Difficulties in the study of sugar structures

Part of the variability seen in saccharide structures is because monosaccharide units may be coupled to each other in many different ways, as opposed to the amino acids of proteins or the nucleotides in DNA, which are always coupled together in a standard fashion.cite paper | author=Kreuger, J | title=Decoding heparan sulfate | date=2001 | url=http://www.diva-portal.org/demo/theses/abstract.xsql?dbid=1499 | accessdate=2008-01-11] The study of saccharide structures is also complicated by the lack of a direct template for their biosynthesis, contrary to the case with proteins where their amino acid sequence is determined by their corresponding gene.

Saccharides are also secondary gene products and as such are generated by the coordinated action of many enzymes in the subcellular compartments of a cell. Thus, the structure of a saccharide may depend on the expression, activity and accessibility of the different biosynthetic enzymes. This means it is not possible to use recombinant DNA technology in order to produce large quantities of saccharides for structural and functional studies as has been used extensively for protein studies.

References

External links

* [http://www.functionalglycomics.org The Functional Glycomics Gateway] . This monthly updated webresource about all aspects of carbohydrate function in biology is a collaboration of Nature and the Consortium for Functional Glycomics.