1c3j: Difference between revisions
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[[Image:1c3j.gif|left|200px]] | [[Image:1c3j.gif|left|200px]] | ||
'''T4 PHAGE BETA-GLUCOSYLTRANSFERASE: SUBSTRATE BINDING AND PROPOSED CATALYTIC MECHANISM''' | {{Structure | ||
|PDB= 1c3j |SIZE=350|CAPTION= <scene name='initialview01'>1c3j</scene>, resolution 1.88Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=UDP:URIDINE-5'-DIPHOSPHATE'>UDP</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/DNA_beta-glucosyltransferase DNA beta-glucosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.27 2.4.1.27] | |||
|GENE= | |||
}} | |||
'''T4 PHAGE BETA-GLUCOSYLTRANSFERASE: SUBSTRATE BINDING AND PROPOSED CATALYTIC MECHANISM''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1C3J is a [ | 1C3J is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1C3J OCA]. | ||
==Reference== | ==Reference== | ||
T4 phage beta-glucosyltransferase: substrate binding and proposed catalytic mechanism., Morera S, Imberty A, Aschke-Sonnenborn U, Ruger W, Freemont PS, J Mol Biol. 1999 Sep 24;292(3):717-30. PMID:[http:// | T4 phage beta-glucosyltransferase: substrate binding and proposed catalytic mechanism., Morera S, Imberty A, Aschke-Sonnenborn U, Ruger W, Freemont PS, J Mol Biol. 1999 Sep 24;292(3):717-30. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/10497034 10497034] | ||
[[Category: Bacteriophage t4]] | [[Category: Bacteriophage t4]] | ||
[[Category: DNA beta-glucosyltransferase]] | [[Category: DNA beta-glucosyltransferase]] | ||
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[[Category: glycosyltransferase]] | [[Category: glycosyltransferase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 10:19:19 2008'' | ||
Revision as of 11:19, 20 March 2008
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| , resolution 1.88Å | |||||||
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| Ligands: | |||||||
| Activity: | DNA beta-glucosyltransferase, with EC number 2.4.1.27 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
T4 PHAGE BETA-GLUCOSYLTRANSFERASE: SUBSTRATE BINDING AND PROPOSED CATALYTIC MECHANISM
OverviewOverview
beta-Glucosyltransferase (BGT) is a DNA-modifying enzyme encoded by bacteriophage T4 which catalyses the transfer of glucose (Glc) from uridine diphosphoglucose (UDP-Glc) to 5-hydroxymethylcytosine (5-HMC) in double-stranded DNA. The glucosylation of T4 phage DNA is part of a phage DNA protection system aimed at host nucleases. We previously reported the first three-dimensional structure of BGT determined from crystals grown in ammonium sulphate containing UDP-Glc. In this previous structure, we did not observe electron density for the Glc moiety of UDP-Glc nor for two large surface loop regions (residues 68-76 and 109-122). Here we report two further BGT co-crystal structures, in the presence of UDP product (form I) and donor substrate UDP-Glc (form II), respectively. Form I crystals are grown in ammonium sulphate and the structure has been determined to 1.88 A resolution (R -factor 19.1 %). Form II crystals are grown in polyethyleneglycol 4000 and the structure has been solved to 2.3 A resolution (R -factor 19.8 %). The form I structure is isomorphous to our previous BGT UDP-Glc structure. The form II structure, however, has allowed us to model the two missing surface loop regions and thus provides the first complete structural description of BGT. In this low-salt crystal form, we see no electron density for the Glc moiety from UDP-Glc similar to previous observations. Biochemical data however, shows that BGT can cleave UDP-Glc in the absence of DNA acceptor, which probably accounts for the absence of Glc in our UDP-Glc substrate structures. The complete BGT structure now provides a basis for detailed modelling of a BGT HMC-DNA ternary complex. By using the structural similarity between the catalytic core of glycogen phosphorylase (GP) and BGT, we have modelled the position of the Glc moiety in UDP-Glc. From these two models, we propose a catalytic mechanism for BGT and identify residues involved in both DNA binding and in stabilizing a "flipped-out" 5-HMC nucleotide.
About this StructureAbout this Structure
1C3J is a Single protein structure of sequence from Bacteriophage t4. Full crystallographic information is available from OCA.
ReferenceReference
T4 phage beta-glucosyltransferase: substrate binding and proposed catalytic mechanism., Morera S, Imberty A, Aschke-Sonnenborn U, Ruger W, Freemont PS, J Mol Biol. 1999 Sep 24;292(3):717-30. PMID:10497034
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