1IXY: Ternary Complex Of T4 Phage Bgt With Udp And A 13 Mer Dna Duplex

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.
PDB ID: 1IXYDownload
MMDB ID: 106344
PDB Deposition Date: 2002/7/9
Updated in MMDB: 2013/01
Experimental Method:
x-ray diffraction
Resolution: 2.5  Å
Source Organism:
synthetic construct
Similar Structures:
Biological Unit for 1IXY: trimeric; determined by author
Molecular Components in 1IXY
Label Count Molecule
Protein (1 molecule)
DNA Beta-glucosyltransferase(Gene symbol: b-gt)
Molecule annotation
Nucleotides(2 molecules)
5'-d(*gp*ap*tp*ap*cp*tp*3drp*ap*gp*ap*tp*ap*g)- 3'
Molecule annotation
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB