@article{91031,
  keywords = {RNA, Sodium Chloride, DNA, Substrate Specificity, Saccharomyces cerevisiae Proteins, Replication Protein A, Oligonucleotides, DNA Helicases},
  author = {Jean-Baptiste Boul{\'e} and Virginia Zakian},
  title = {The yeast Pif1p DNA helicase preferentially unwinds RNA DNA substrates.},
  abstract = { Pif1p is the prototypical member of the PIF1 family of DNA helicases, a subfamily of SFI helicases conserved from yeast to humans. Baker{\textquoteright}s yeast Pif1p is involved in the maintenance of mitochondrial, ribosomal and telomeric DNA and may also have a general role in chromosomal replication by affecting Okazaki fragment maturation. Here we investigate the substrate preferences for Pif1p. The enzyme was preferentially active on RNA-DNA hybrids, as seen by faster unwinding rates on RNA-DNA hybrids compared to DNA-DNA hybrids. When using forked substrates, which have been shown previously to stimulate the enzyme, Pif1p demonstrated a preference for RNA-DNA hybrids. This preferential unwinding could not be correlated to preferential binding of Pif1p to the substrates that were the most readily unwound. Although the addition of the single-strand DNA-binding protein replication protein A (RPA) stimulated the helicase reaction on all substrates, it did not diminish the preference of Pif1p for RNA-DNA substrates. Thus, forked RNA-DNA substrates are the favored substrates for Pif1p in vitro. We discuss these findings in terms of the known biological roles of the enzyme. },
  year = {2007},
  journal = {Nucleic Acids Res},
  volume = {35},
  pages = {5809-18},
  issn = {1362-4962},
  doi = {10.1093/nar/gkm613},
  language = {eng},
}