DNA is an underrepresented target for small molecule therapeutic agents. One reason for the dearth of DNA targeted drugs is that the fundamental molecular mechanisms that govern sequence- and structural-selective ligands to DNA remain poorly understood. In order to develop design principles for targeting specific DNA sites, a thorough understanding of the binding mechanisms of existing compounds that bind to DNA with unique types of selectivity is needed. The long-range goal of this project is to understand the mechanism of DNA intercalation reactions, with particular emphasis on the energetic basis of sequence- and structural-selective binding. Renewal is sought for a successful and highly productive basic science program that has produced several promising avenues for DNA-targeted drug development. Four-stranded G-quadruplex DNA structures have emerged as important functional elements within the genome, and represent important new targets for therapeutic drugs. G-quadruplexes are functional elements that are important in telomere biology, and are emerging as important control elements in the expression of many genes, particularly oncogenes. Research in the next funding period will focus on biophysical studies of G-quadruplex structure, folding and stability, and on their selective interactions specific quadruplex structures with drug-like molecules.
Specific aims i nclude: 1. Determination of the structure of the 200 nt single-stranded DNA overhang that is a conserved feature of human telomeres. 2. Determination of the thermodynamic stability of higher-order quadruplex structures and the kinetics of the folding. 3. Determination of the thermodynamics and kinetics of drug binding to specific quadruplex structures, including the higher-order structures in telomeric DNA and the G-quadruplex "silencer" element found in the c-myc promoter. The results of these proposed studies will deepen our understanding of the structure and stability of functionally important G-quadruplexes, and will provide fundamental mechanistic information of use in the rational design of new small molecules to selectively target functionally important quadruplex structures.

Public Health Relevance

G-quadruplexes are four-stranded DNA structures that are thought to be functionally import elements in the human genome. Quadruplexes have emerged as potential drug targets. The proposed project will use computational and biophysical methods to study the structure, stability, and drug binding of functionally significant quadruplex structures. The results will be of fundamental use for guiding the design of new drugs targeted toward quadruplexes.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
Project #
Application #
Study Section
Macromolecular Structure and Function B Study Section (MSFB)
Program Officer
Misra, Raj N
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Louisville
Internal Medicine/Medicine
Schools of Medicine
United States
Zip Code
Le, Huy T; Dean, William L; Buscaglia, Robert et al. (2014) An investigation of G-quadruplex structural polymorphism in the human telomere using a combined approach of hydrodynamic bead modeling and molecular dynamics simulation. J Phys Chem B 118:5390-405
Gray, Robert D; Trent, John O; Chaires, Jonathan B (2014) Folding and unfolding pathways of the human telomeric G-quadruplex. J Mol Biol 426:1629-50
Buscaglia, R; Gray, R D; Chaires, J B (2013) Thermodynamic characterization of human telomere quadruplex unfolding. Biopolymers 99:1006-18
Le, Vu H; Buscaglia, Robert; Chaires, Jonathan B et al. (2013) Modeling complex equilibria in isothermal titration calorimetry experiments: thermodynamic parameters estimation for a three-binding-site model. Anal Biochem 434:233-41
Buscaglia, Robert; Miller, M Clarke; Dean, William L et al. (2013) Polyethylene glycol binding alters human telomere G-quadruplex structure by conformational selection. Nucleic Acids Res 41:7934-46
Gray, Robert D; Chaires, Jonathan B (2012) Isothermal folding of G-quadruplexes. Methods 57:47-55
Buscaglia, Robert; Jameson, David M; Chaires, Jonathan B (2012) G-quadruplex structure and stability illuminated by 2-aminopurine phasor plots. Nucleic Acids Res 40:4203-15
Gray, Robert D; Chaires, Jonathan B (2011) Analysis of multidimensional G-quadruplex melting curves. Curr Protoc Nucleic Acid Chem Chapter 17:Unit17.4
Petraccone, Luigi; Spink, Charles; Trent, John O et al. (2011) Structure and stability of higher-order human telomeric quadruplexes. J Am Chem Soc 133:20951-61
Holt, Patrick A; Buscaglia, Robert; Trent, John O et al. (2011) A Discovery Funnel for Nucleic Acid Binding Drug Candidates. Drug Dev Res 72:178-186

Showing the most recent 10 out of 102 publications