Nucleotide sugars metabolism

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Nucleotide sugars are a group of biochemicals that act as donors for sugar residues in the glycosylation reactions that produce polysaccharides in metabolism.[1] They are substrates for glycosyltransferases.[2] Various forms of these molecules exist, with GDP often being used in eukaryotes for the donation of disaccharides, such as GDP-mannose, and UDP for monosaccharides such as UDP-glucose and UDP-galactose. The nucleotide sugars are also intermediates in nucleotide sugar interconversions that produce some of the activated sugars needed for glycosylation reactions.[1]

Nucleotide sugar metabolism is particularly well-studied in 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.[3][4] These glycoconjugates are virulence factors and components of the bacterial cell wall. These pathways are also studied in plants, but here the enzymes involved are less well understood.[5]

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.[6][7]

[edit] References

  1. ^ a b Ginsburg V (1978). "Comparative biochemistry of nucleotide-linked sugars". Prog. Clin. Biol. Res. 23: 595–600. PMID 351635. 
  2. ^ Rademacher T, Parekh R, Dwek R (1988). "Glycobiology". Annu Rev Biochem 57: 785–838. doi:10.1146/annurev.bi.57.070188.004033. PMID 3052290. 
  3. ^ 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. 
  4. ^ 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. PMID 12029057. 
  5. ^ 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. 
  6. ^ 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. PMID 16981043. 
  7. ^ 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. 
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Types of nucleotide sugars
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