title: Requirement of Watson-Crick hydrogen bonding for DNA synthesis by yeast DNA polymerase eta.
abstract: Classical high-fidelity DNA polymerases discriminate between the correct and incorrect nucleotides by using geometric constraints imposed by the tight fit of the active site with the incipient base pair. Consequently, Watson-Crick (W-C) hydrogen bonding between the bases is not required for the efficiency and accuracy of DNA synthesis by these polymerases. DNA polymerase eta (Poleta) is a low-fidelity enzyme able to replicate through DNA lesions. Using difluorotoluene, a nonpolar isosteric analog of thymine unable to form W-C hydrogen bonds with adenine, we found that the efficiency and accuracy of nucleotide incorporation by Poleta are severely impaired. From these observations, we suggest that W-C hydrogen bonding is required for DNA synthesis by Poleta; in this regard, Poleta differs strikingly from classical high-fidelity DNA polymerases.
authors.affiliation: Sealy Center for Molecular Science, University of Texas Medical Branch at Galveston, Galveston, Texas 77555-1061, USA.
authors.forename: M Todd
authors.initials: MT
authors.lastname: Washington
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Helquist
authors.forename: Eric T
authors.initials: ET
authors.lastname: Kool
authors.forename: Louise
authors.initials: L
authors.lastname: Prakash
authors.forename: Satya
authors.initials: S
authors.lastname: Prakash
mesh_terms: D004247:DNA / Q000096:biosynthesis* / Q000737:chemistry; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D006860:Hydrogen Bonding; D007700:Kinetics; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism; D014050:Toluene / Q000031:analogs & derivatives* / Q000737:chemistry; D015003:Yeasts / Q000235:genetics / Q000378:metabolism; D000099270:Y-Family DNA Polymerases
chemical_list: D004247:DNA; D004259:DNA-Directed DNA Polymerase; D005656:Fungal Proteins; D009711:Nucleotides; D014050:Toluene; C110527:difluorotoluene; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases