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Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
11:42

Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes

Published on: November 1, 2012

Crystal structure of Δ-[Ru(bpy)₂dppz]²⁺ bound to mismatched DNA reveals side-by-side metalloinsertion and

Hang Song1, Jens T Kaiser, Jacqueline K Barton

  • 1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.

Nature Chemistry
|July 25, 2012
PubMed

Insights

Ruthenium complexes bind DNA mismatches via metalloinsertion, ejecting mispaired bases. This structural insight aids developing novel cancer diagnostics and therapeutics targeting DNA repair deficiencies.

Area of Science:

  • Biochemistry
  • Structural Biology
  • Chemical Biology

Background:

  • DNA mismatches are linked to cancer development due to deficiencies in DNA mismatch repair.
  • Metal complexes with bulky intercalating ligands are utilized as probes for DNA mismatches.

Purpose of the Study:

  • To determine the high-resolution crystal structure of a ruthenium complex bound to DNA mismatches.
  • To elucidate the binding mechanism of ruthenium complexes at both mismatched and well-matched DNA sites.

Main Methods:

  • High-resolution X-ray crystallography (0.92 Å) was used to determine the structure.
  • The study utilized the ruthenium 'light switch' complex Δ-[Ru(bpy)(2)dppz](2+) bound to an oligonucleotide with AA mismatches.

Main Results:

  • The crystal structure revealed metalloinsertion as the binding mode for mismatches, ejecting mispaired adenosines.
  • Additional ruthenium complexes were observed intercalated at well-matched sites.
  • The binding involves stabilization in the minor groove via stacking interactions.

Conclusions:

  • Metalloinsertion and metallointercalation are general DNA binding modes for ruthenium complexes.
  • Understanding these binding modes is crucial for developing DNA mismatch-targeting cancer diagnostics and therapeutics.

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