1JIX: T4 Phage Bgt In Complex With Ca2+

Citation:
Abstract
beta-Glucosyltransferase (BGT) is a DNA-modifying enzyme encoded by bacteriophage T4 that transfers glucose from uridine diphosphoglucose to 5-hydroxymethyl cytosine bases of phage T4 DNA. We report six X-ray structures of the substrate-free and the UDP-bound enzyme. Four also contain metal ions which activate the enzyme, including Mg(2+) in forms 1 and 2 and Mn(2+) or Ca(2+). The substrate-free BGT structure differs by a domain movement from one previously determined in another space group. Further domain movements are seen in the complex with UDP and the four UDP-metal complexes. Mg(2+), Mn(2+) and Ca(2+) bind near the beta-phosphate of the nucleotide, but they occupy slightly different positions and have different ligands depending on the metal and the crystal form. Whilst the metal site observed in these complexes with the product UDP is not compatible with a role in activating glucose transfer, it approximates the position of the positive charge in the oxocarbonium ion thought to form on the glucose moiety of the substrate during catalysis.
PDB ID: 1JIXDownload
MMDB ID: 16765
PDB Deposition Date: 2001/7/3
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 1.65  Å
Source Organism:
Similar Structures:
Biological Unit for 1JIX: monomeric; determined by author
Molecular Components in 1JIX
Label Count Molecule
Protein (1 molecule)
1
DNA Beta-glucosyltransferase(Gene symbol: b-gt)
Molecule annotation
Chemicals (2 molecules)
1
1
2
1
* Click molecule labels to explore molecular sequence information.

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