In nucleotide sugar metabolism a group of biochemicals known as nucleotide sugars act as donors for sugar residues in the glycosylation reactions that produce polysaccharides.[1] They are substrates for glycosyltransferases.[2] The nucleotide sugars are also intermediates in nucleotide sugar interconversions that produce some of the activated sugars needed for glycosylation reactions.[1] Since most glycosylation takes place in the endoplasmic reticulum and golgi apparatus, there are a large family of nucleotide sugar transporters that allow nucleotide sugars to move from the cytoplasm, where they are produced, into the organelles where they are consumed.[3][4]
Nucleotide sugar metabolism is particularly well-studied in yeast,[5] fungal pathogens,[6] and bacterial pathogens, such as E. coli and Mycobacterium tuberculosis, since these molecules are required for the synthesis of glycoconjugates on the surfaces of these organisms.[7][8] These glycoconjugates are virulence factors and components of the fungal and bacterial cell wall. These pathways are also studied in plants, but here the enzymes involved are less well understood.[9]
References
edit- ^ a b Ginsburg V (1978). "Comparative biochemistry of nucleotide-linked sugars". Prog. Clin. Biol. Res. 23: 595–600. PMID 351635.
- ^ Rademacher T, Parekh R, Dwek R (1988). "Glycobiology". Annu Rev Biochem. 57: 785–838. doi:10.1146/annurev.bi.57.070188.004033. PMID 3052290.
- ^ Handford M, Rodriguez-Furlán C, Orellana A (2006). "Nucleotide-sugar transporters: structure, function and roles in vivo". Braz. J. Med. Biol. Res. 39 (9): 1149–58. doi:10.1590/s0100-879x2006000900002. PMID 16981043.
- ^ Gerardy-Schahn R, Oelmann S, Bakker H (2001). "Nucleotide sugar transporters: biological and functional aspects". Biochimie. 83 (8): 775–82. doi:10.1016/S0300-9084(01)01322-0. PMID 11530210.
- ^ Dean N, Zhang YB, Poster JB (1997). "The VRG4 gene is required for GDP-mannose transport into the lumen of the Golgi in the yeast, Saccharomyces cerevisiae". J. Biol. Chem. 272 (50): 31908–14. doi:10.1074/jbc.272.50.31908. PMID 9395539.
- ^ Nishikawa A.; Poster J.B.; Jigami Y.; Dean N. (2002). "Molecular and phenotypic analysis of CaVRG4, encoding an essential Golgi apparatus GDP-mannose transporter". J. Bacteriol. 184 (50): 29–42. doi:10.1128/JB.184.1.29-42.2002. PMC 134776. PMID 11741841.
- ^ Samuel G, Reeves P (2003). "Biosynthesis of O-antigens: genes and pathways involved in nucleotide sugar precursor synthesis and O-antigen assembly". Carbohydr. Res. 338 (23): 2503–19. doi:10.1016/j.carres.2003.07.009. PMID 14670712.
- ^ Ma Y, Pan F, McNeil M (2002). "Formation of dTDP-rhamnose is essential for growth of mycobacteria". J. Bacteriol. 184 (12): 3392–5. doi:10.1128/JB.184.12.3392-3395.2002. PMC 135104. PMID 12029057.
- ^ Seifert GJ (2004). "Nucleotide sugar interconversions and cell wall biosynthesis: how to bring the inside to the outside". Curr. Opin. Plant Biol. 7 (3): 277–84. doi:10.1016/j.pbi.2004.03.004. PMID 15134748.
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