1N14

Structure and Dynamics of Thioguanine-modified Duplex DNA in Comparison with Unmodified DNA; Structure of Unmodified Duplex DNA


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure and dynamics of thioguanine-modified duplex DNA

Somerville, L.Krynetski, E.Y.Krynetskaia, N.F.Beger, R.D.Zhang, W.Marhefka, C.A.Evans, W.E.Kriwacki, R.W.

(2003) J.Biol.Chem. 278: 1005-1011

  • DOI: 10.1074/jbc.M204243200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Mercaptopurine and thioguanine, two of the most widely used antileukemic agents, exert their cytotoxic, therapeutic effects by being incorporated into DNA as deoxy-6-thioguanosine. However, the molecular mechanism(s) by which incorporation of these t ...

    Mercaptopurine and thioguanine, two of the most widely used antileukemic agents, exert their cytotoxic, therapeutic effects by being incorporated into DNA as deoxy-6-thioguanosine. However, the molecular mechanism(s) by which incorporation of these thiopurines into DNA translates into cytotoxicity is unknown. The solution structure of thioguanine-modified duplex DNA presented here shows that the effects of the modification on DNA structure were subtle and localized to the modified base pair. Specifically, thioguanine existed in the keto form, formed weakened Watson-Crick hydrogen bonds with cytosine and caused a modest approximately 10 degrees opening of the modified base pair toward the major groove. In contrast, thioguanine significantly altered base pair dynamics, causing an approximately 80-fold decrease in the base pair lifetime with cytosine compared with normal guanine. This perturbation was consistent with the approximately 6 degrees C decrease in DNA melting temperature of the modified oligonucleotide, the 1.13 ppm upfield shift of the thioguanine imino proton resonance, and the large increase in the exchange rate of the thioguanine imino proton with water. Our studies provide new mechanistic insight into the effects of thioguanine incorporation into DNA at the level of DNA structure and dynamics, provide explanations for the effects of thioguanine incorporation on the activity of DNA-processing enzymes, and provide a molecular basis for the specific recognition of thioguanine-substituted sites by proteins. These combined effects likely cooperate to produce the cellular responses that underlie the therapeutic effects of thiopurines.


    Organizational Affiliation

    Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsLengthOrganism
5'-D(*GP*CP*TP*AP*AP*GP*GP*AP*AP*AP*GP*CP*C)-3'A13N/A
Entity ID: 2
MoleculeChainsLengthOrganism
5'-D(*GP*GP*CP*TP*TP*TP*CP*CP*TP*TP*AP*GP*C)-3'B13N/A
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum 

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-10-23
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance