1ixy
From Proteopedia
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Ternary complex of T4 phage BGT with UDP and a 13 mer DNA duplex
Overview
T4 phage beta-glucosyltransferase (BGT) modifies T4 DNA. We crystallized, BGT with UDP-glucose and a 13mer DNA fragment containing an abasic site., We obtained two crystal structures of a ternary complex BGT-UDP-DNA at, 1.8A and 2.5A resolution, one with a Tris molecule and the other with a, metal ion at the active site. Both structures reveal a large distortion in, the bound DNA. BGT flips the deoxyribose moiety at the abasic site to an, extra-helical position and induces a 40 degrees bend in the DNA with a, marked widening of the major groove. The Tris molecule mimics the glucose, moiety in its transition state. The base-flipping mechanism, which has so, far been observed only for glycosylases, methyltransferases and, endonucleases, is now reported for a glucosyltransferase. BGT is unique in, binding and inserting a loop into the DNA duplex through the major groove, only. Furthermore, BGT compresses the backbone DNA one base further than, the target base on the 3'-side.
About this Structure
1IXY is a Single protein structure of sequence from Bacteriophage t4 with MG, UDP and MPD as ligands. Active as DNA beta-glucosyltransferase, with EC number 2.4.1.27 Full crystallographic information is available from OCA.
Reference
A base-flipping mechanism for the T4 phage beta-glucosyltransferase and identification of a transition-state analog., Lariviere L, Morera S, J Mol Biol. 2002 Nov 29;324(3):483-90. PMID:12445783
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