1bgu
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CRYSTAL STRUCTURE OF THE DNA MODIFYING ENZYME BETA-GLUCOSYLTRANSFERASE IN THE PRESENCE AND ABSENCE OF THE SUBSTRATE URIDINE DIPHOSPHOGLUCOSE
OverviewOverview
Bacteriophage T4 beta-glucosyltransferase (EC 2.4.1.27) catalyses the, transfer of glucose from uridine diphosphoglucose to hydroxymethyl groups, of modified cytosine bases in T4 duplex DNA forming beta-glycosidic, linkages. The enzyme forms part of a phage DNA protection system. We have, solved and refined the crystal structure of recombinant, beta-glucosyltransferase to 2.2 A resolution in the presence and absence, of the substrate, uridine diphosphoglucose. The structure comprises two, domains of similar topology, each reminiscent of a nucleotide binding, fold. The two domains are separated by a central cleft which generates a, concave surface along one side of the molecule. The substrate-bound, complex reveals only clear electron density for the uridine diphosphate, portion of the substrate. The UDPG is bound in a pocket at the bottom of, the cleft between the two domains and makes extensive hydrogen bonding, contacts with residues of the C-terminal domain only. The domains undergo, a rigid body conformational change causing the structure to adopt a more, closed conformation upon ligand binding. The movement of the domains is, facilitated by a hinge region between residues 166 and 172. Electrostatic, surface potential calculations reveal a large positive potential along the, concave surface of the structure, suggesting a possible site for duplex, DNA interaction.
About this StructureAbout this Structure
1BGU is a Single protein structure of sequence from Bacteriophage t4 with UDP as ligand. Active as DNA beta-glucosyltransferase, with EC number 2.4.1.27 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the DNA modifying enzyme beta-glucosyltransferase in the presence and absence of the substrate uridine diphosphoglucose., Vrielink A, Ruger W, Driessen HP, Freemont PS, EMBO J. 1994 Aug 1;13(15):3413-22. PMID:8062817
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