Molecular dynamics simulations and coupled nucleotide substitution experiments indicate the nature of A center dot A base pairing and a putative structure of the coralyne-induced homo-adenine duplex

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2009-12-01

Author

Joung, In Suk
Persil Çetinkol, Özgül
HUD, Nicholas V.
Cheatham, Thomas E.

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Coralyne is an alkaloid drug that binds homo-adenine DNA (and RNA) oligonucleotides more tightly than it does Watson-Crick DNA. Hud's laboratory has shown that poly(dA) in the presence of coralyne forms an anti-parallel duplex, however attempts to determine the structure by NMR spectroscopy and X-ray crystallography have been unsuccessful. Assuming adenine-adenine hydrogen bonding between the two poly(dA) strands, we constructed 40 hypothetical homo-(dA) anti-parallel duplexes and docked coralyne into the six most favorable duplex structures. The two most stable structures had trans glycosidic bonds, but distinct pairing geometries, i.e. either Watson-Crick Hoogsteen (transWH) or Watson-Crick Watson-Crick (transWW) with stability of transWH > transWW. To narrow down the possibilities, 7-deaza adenine base substitutions (dA7) were engineered into homo-(dA) sequences. These substitutions significantly reduced the thermal stability of the coralyne-induced homo-(dA) structure. These experiments strongly suggest the involvement of N7 in the coralyne-induced A center dot A base pairs. Moreover, due to the differential effect on melting as a function of the location of the dA7 mutations, these results are consistent with the N1-N7 base pairing of the transWH pairs. Together, the simulation and base substitution experiments predict that the coralyne-induced homo-(dA) duplex structure adopts the transWH geometry.

Subject Keywords

Genetics

URI

https://hdl.handle.net/11511/48056

Journal

NUCLEIC ACIDS RESEARCH

DOI

https://doi.org/10.1093/nar/gkp730

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Department of Chemistry, Article

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Citation Formats

I. S. Joung, Ö. Persil Çetinkol, N. V. HUD, and T. E. Cheatham, “Molecular dynamics simulations and coupled nucleotide substitution experiments indicate the nature of A center dot A base pairing and a putative structure of the coralyne-induced homo-adenine duplex,” NUCLEIC ACIDS RESEARCH, pp. 7715–7727, 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48056.