Capillary electrophoresis as a probe of enantiospecific interactions between photoactive transition metal complexes and DNA

Recently, we have demonstrated the capacity to separate chiral transition metal (TM) complexes of the type [M(diimine)3]n+ using CE buffers containing chiral tartrate salts. In separate work, several chromium(III)‐tris‐diimine complexes in particular have been shown to bind enantioselectively with c...

Full description

Saved in:
Bibliographic Details
Published in:Electrophoresis 2003-08, Vol.24 (15), p.2704-2710
Main Authors: Schaeper, James P., Nelsen, Lori A., Shupe, M. Alyson, Herbert, Brad J., Kane-Maguire, Noel A. P., Wheeler, John F.
Format: Article
Language:English
Subjects:
Capillary electrophoresis
Chiral separation
DNA
DNA - chemistry
DNA - metabolism
Electrophoresis, Capillary - methods
Imines
Intercalating Agents - chemistry
Organometallic Compounds - chemistry
Photochemistry
Stereoisomerism
Transition Elements - chemistry
Transition metal
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Recently, we have demonstrated the capacity to separate chiral transition metal (TM) complexes of the type [M(diimine)3]n+ using CE buffers containing chiral tartrate salts. In separate work, several chromium(III)‐tris‐diimine complexes in particular have been shown to bind enantioselectively with calf‐thymus (CT) DNA, and a qualitative assessment of the relative strength and enantiospecificity of this interaction is of significant interest in the characterization of these complexes as potential DNA photocleavage agents. Here, we describe two convenient approaches to investigate such binding behavior using chiral CE. For complexes with lower DNA affinities exhibiting primarily surface binding, DNA itself is used as the chiral resolving agent in the electrophoretic buffer. In this approach, resolution of the TM complexes into their Λ and Δ isomers is achieved with the isomer eluting later exhibiting superior binding affinity toward DNA. For more strongly bound TM complexes containing ligands known to intercalate with DNA, the [Cr(diimine)3]3+ complexes are preincubated with oligonucleotide and subsequently enantiomerically resolved in a dibenzoyl‐L‐tartrate buffer system that facilitates analysis of the unbound TM species only. Differences in isomer binding affinity are distinguished by the relative peak areas of the Λ‐ and Δ‐isomers, and relative binding strengths of different complexes can be inferred from comparison of the total amount of unbound complex at equivalent DNA/TM ratios.
ISSN:0173-0835
1522-2683
DOI:10.1002/elps.200305488