Pairing Geometry of the Hydrophobic Thymine Analogue 2,4-Difluorotoluene in Duplex DNA as Analyzed by X-ray Crystallography
Certain DNA polymerases (pols) were found to efficiently insert A opposite the hydrophobic T isostere 2,4-difluorotoluene (F) and vice versa, resulting in the widely held belief that some pols rely on shape rather than H-bonding for accurate replication. Using X-ray crystallography we have analyzed the geometry of F:A pairs in duplex DNA and observed a distance between fluorine and the exocyclic amino group of A that is consistent with a H-bond, thus challenging the assumption that the F analogue is unable to engage in H-bonding as well as the steric hypothesis of DNA replication. Therefore, shape and H-bonding are inherently related, and steric constraints at a pol active site, or conferred by stacking or the DNA backbone conformation, may enable H-bonding by F.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1005934
- Journal Information:
- J. Am. Chem. Soc., Vol. 131, Issue (35) ; 09, 2009; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- ENGLISH
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