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Single-molecule Manipulation of G-quadruplexes by Magnetic Tweezers
Published on: September 19, 2017
Selectivity in ligand recognition of G-quadruplex loops
Nancy H Campbell1, Manisha Patel, Amina B Tofa
1Cancer Research UK Biomolecular Structure Group, The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK.
Biochemistry
|January 29, 2009
Summary
Disubstituted acridine ligands bind to DNA G-quadruplexes. Loop structure significantly impacts ligand selectivity, with diagonal loops accommodating larger groups than propeller loops.
Area of Science:
- Structural biology
- Medicinal chemistry
- DNA nanotechnology
Background:
- DNA G-quadruplexes are non-canonical DNA structures implicated in various biological processes.
- Small molecules targeting G-quadruplexes are of interest for therapeutic applications.
- Ligand binding to G-quadruplexes is influenced by their unique structural features.
Purpose of the Study:
- To investigate the cocrystallization of disubstituted acridine ligands with a bimolecular DNA G-quadruplex.
- To analyze the structural basis of ligand-G-quadruplex interactions.
- To determine the influence of G-quadruplex loop structure on ligand selectivity.
Main Methods:
- Cocrystallization of acridine ligands with a bimolecular G-quadruplex.
- X-ray crystallography to determine high-resolution structures.
- Analysis of ligand-G-quadruplex interfaces and cavity sizes.
Main Results:
- Disubstituted acridine ligands were successfully cocrystallized with the G-quadruplex.
- Crystal structures revealed a large cavity in the diagonal loop of the G-quadruplex.
- This cavity accommodates cyclic amino end groups of varying sizes.
- Steric constraints were observed in propeller loops, unlike the diagonal loop.
Conclusions:
- The diagonal loop of G-quadruplexes provides significant space for ligand end groups.
- Loop conformation critically influences ligand selectivity for specific G-quadruplex folds.
- Understanding loop structure is key for designing selective G-quadruplex-targeting agents.
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