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Crystal structure of the DNA modifying enzyme beta‐glucosyltransferase in the presence and absence of the substrate uridine diphosphoglucose.
Author(s) -
Vrielink A.,
Rüger W.,
Driessen H.P.,
Freemont P.S.
Publication year - 1994
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1994.tb06646.x
Subject(s) - biology , glucosyltransferase , uridine , substrate (aquarium) , dna , biochemistry , beta (programming language) , enzyme , microbiology and biotechnology , crystallography , rna , gene , chemistry , ecology , programming language , computer science
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.