We apologize for Proteopedia being slow to respond. For the past two years, a new implementation of Proteopedia has been being built. Soon, it will replace this 18-year old system. All existing content will be moved to the new system at a date that will be announced here.
Placing an 2-nitrobenzyl group on O-6 of the galactosyl residue in uridine-5'-diphosphogalactose (UDP-Gal) gives 6''-O-2-nitrobenzyl-UDP-Gal that is shown to be inactive as a donor substrate for beta-(1-->4)-galactosyltransferase (GalT). On irradiation at 365 nm, the nitrobenzyl group is completely removed yielding native UDP-Gal that then transfers normally to produce the expected betaGal-(1-->4)-betaGlcNAc disaccharidic linkage. 6''-O-2-Nitrobenzyl-UDP-Gal thus fulfils the minimum requirements of a 'caged' UDP-Gal for application in time-resolved crystallographic studies of beta-(1-->4)-GalT.
+
Glycosyltransferases (GTs) catalyse the sequential addition of monosaccharides to specific acceptor molecules and play major roles in key biological processes. GTs are classified into two main families depending on the inverted or retained stereochemistry of the glycosidic bond formed during the reaction. While the mechanism of inverting enzymes is well characterized, the precise nature of retaining GTs is still a matter of much debate. In an attempt to clarify this issue, studies were initiated to identify reaction-intermediate states by using a crystallographic approach based on caged substrates. In this paper, two distinct structures of AA(Gly)B, a dual-specificity blood group synthase, are described in complex with a UDP-galactose derivative in which the O6'' atom is protected by a 2-nitrobenzyl group. The distinct conformations of the caged substrate in both structures of the enzyme illustrate the highly dynamic nature of its active site. An attempt was also made to photolyse the caged compound at low temperature, which unfortunately is not possible without damaging the uracil group as well. These results pave the way for kinetic crystallography experiments aiming at trapping and characterizing reaction-intermediate states in the mechanism of enzymatic glycosyl transfer.
-
Synthesis and photolytic activation of 6''-O-2-nitrobenzyl uridine-5'-diphosphogalactose: a 'caged' UDP-Gal derivative.,Mannerstedt K, Hindsgaul O Carbohydr Res. 2008 Apr 7;343(5):875-81. doi: 10.1016/j.carres.2008.01.021. Epub , 2008 Jan 26. PMID:18275942<ref>PMID:18275942</ref>
+
Structures of a human blood group glycosyltransferase in complex with a photo-activatable UDP-Gal derivative reveal two different binding conformations.,Jorgensen R, Batot G, Mannerstedt K, Imberty A, Breton C, Hindsgaul O, Royant A, Palcic MM Acta Crystallogr F Struct Biol Commun. 2014 Aug 1;70(Pt 8):1015-21. doi:, 10.1107/S2053230X1401259X. Epub 2014 Jul 23. PMID:25084373<ref>PMID:25084373</ref>
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
Revision as of 06:23, 13 August 2014
Crystal structure of the Fucosylgalactoside alpha N- acetylgalactosaminyltransferase (GTA, cisAB mutant L266G, G268A) in complex with NPE caged UDP-Gal (C222(1) space group)
3zgg is a 1 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Glycosyltransferases (GTs) catalyse the sequential addition of monosaccharides to specific acceptor molecules and play major roles in key biological processes. GTs are classified into two main families depending on the inverted or retained stereochemistry of the glycosidic bond formed during the reaction. While the mechanism of inverting enzymes is well characterized, the precise nature of retaining GTs is still a matter of much debate. In an attempt to clarify this issue, studies were initiated to identify reaction-intermediate states by using a crystallographic approach based on caged substrates. In this paper, two distinct structures of AA(Gly)B, a dual-specificity blood group synthase, are described in complex with a UDP-galactose derivative in which the O6 atom is protected by a 2-nitrobenzyl group. The distinct conformations of the caged substrate in both structures of the enzyme illustrate the highly dynamic nature of its active site. An attempt was also made to photolyse the caged compound at low temperature, which unfortunately is not possible without damaging the uracil group as well. These results pave the way for kinetic crystallography experiments aiming at trapping and characterizing reaction-intermediate states in the mechanism of enzymatic glycosyl transfer.
Structures of a human blood group glycosyltransferase in complex with a photo-activatable UDP-Gal derivative reveal two different binding conformations.,Jorgensen R, Batot G, Mannerstedt K, Imberty A, Breton C, Hindsgaul O, Royant A, Palcic MM Acta Crystallogr F Struct Biol Commun. 2014 Aug 1;70(Pt 8):1015-21. doi:, 10.1107/S2053230X1401259X. Epub 2014 Jul 23. PMID:25084373[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Jorgensen R, Batot G, Mannerstedt K, Imberty A, Breton C, Hindsgaul O, Royant A, Palcic MM. Structures of a human blood group glycosyltransferase in complex with a photo-activatable UDP-Gal derivative reveal two different binding conformations. Acta Crystallogr F Struct Biol Commun. 2014 Aug 1;70(Pt 8):1015-21. doi:, 10.1107/S2053230X1401259X. Epub 2014 Jul 23. PMID:25084373 doi:http://dx.doi.org/10.1107/S2053230X1401259X
