PMID: 21667997

Authors:

Xia S, Konigsberg WH, Wang J

Title:

Hydrogen-Bonding Capability of a Templating Difluorotoluene Nucleotide Residue in an RB69 DNA Polymerase Ternary Complex.

Journal:

J Am Chem Soc. 2011 Jun 15.

Abstract:

Results obtained using 2,4-difluorotoluene nucleobase (dF) as a nonpolar thymine isostere by Kool and colleagues challenged the Watson-Crick dogma that hydrogen bonds between complementary bases are an absolute requirement for accurate DNA replication. Here, we report crystal structure of an RB69 DNA polymerase L561A/S565G/Y567A triple mutant ternary complex with a templating dF opposite dTTP at 1.8 A-resolution. In this structure, direct hydrogen bonds were observed between: (i) dF and the incoming dTTP, (ii) dF and residue G568 of the polymerase, and (iii) dF and ordered water molecules surrounding the nascent base pair. Therefore, this structure provides evidence that a templating dF can form novel hydrogen bonds with the incoming dTTP and with the enzyme that differ from those formed with a templating dT.