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Updated: Jul 24, 2026
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Genome-wide Mapping of Drug-DNA Interactions in Cells with COSMIC (Crosslinking of Small Molecules to Isolate Chromatin)
Published on: January 20, 2016
Distamycin A modulates the sequence specificity of DNA alkylation by duocarmycin A
H Sugiyama1, C Lian, M Isomura
1Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, Japan.
Summary
Duocarmycin A (Duo) typically targets DNA
Area of Science:
- DNA alkylation
- Drug-DNA interactions
- Structural biology
Background:
- Duocarmycin A (Duo) is a DNA alkylating agent that preferentially targets adenine (A) in A+T-rich sequences.
- Duo binds to the DNA minor groove as a monomer for efficient alkylation.
Purpose of the Study:
- To investigate how distamycin A (Dist) affects Duo's DNA alkylation site.
- To elucidate the structural basis for modulated DNA alkylation by Duo and Dist.
Main Methods:
- High-performance liquid chromatography (HPLC) for product analysis.
- Nuclear Overhauser effect (NOE)-restrained refinement using 750 MHz 2D NOE spectroscopy.
- Determination of the 3D structure of the ternary Duo/Dist/DNA complex.
Main Results:
- Distamycin A (Dist) redirects Duocarmycin A (Duo) alkylation from adenine (A) to guanine (G) in G+C-rich sequences.
- Cooperative binding of a Duo-Dist heterodimer to the DNA minor groove facilitates efficient G-N3 alkylation.
- The refined NMR structure of the ternary complex explains the sequence-specific alkylation modulation.
Conclusions:
- Cooperative binding between structurally distinct natural products (Duo and Dist) can predictably alter DNA alkylation selectivity.
- This study presents the first demonstration of Duo DNA alkylation via cooperative binding with another natural product.
- The findings suggest a novel strategy for modifying DNA alkylation patterns.
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