Hydrogen-bonding capability of a templating difluorotoluene nucleotide residue in an RB69 DNA polymerase ternary complex.
Publication Type:Journal Article
Source:J Am Chem Soc, Volume 133, Issue 26, p.10003-5 (2011)
Keywords:Crystallography, X-Ray, DNA-Directed DNA Polymerase, Hydrogen Bonding, Models, Molecular, Mutation, Protein Structure, Tertiary, Thymine Nucleotides, Toluene, Viral Proteins
<p>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 Å-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.</p>