title: Mechanism for priming DNA synthesis by yeast DNA polymerase α.
abstract: The DNA Polymerase α (Pol α)/primase complex initiates DNA synthesis in eukaryotic replication. In the complex, Pol α and primase cooperate in the production of RNA-DNA oligonucleotides that prime synthesis of new DNA. Here we report crystal structures of the catalytic core of yeast Pol α in unliganded form, bound to an RNA primer/DNA template and extending an RNA primer with deoxynucleotides. We combine the structural analysis with biochemical and computational data to demonstrate that Pol α specifically recognizes the A-form RNA/DNA helix and that the ensuing synthesis of B-form DNA terminates primer synthesis. The spontaneous release of the completed RNA-DNA primer by the Pol α/primase complex simplifies current models of primer transfer to leading- and lagging strand polymerases. The proposed mechanism of nucleotide polymerization by Pol α might contribute to genomic stability by limiting the amount of inaccurate DNA to be corrected at the start of each Okazaki fragment. DOI:http://dx.doi.org/10.7554/eLife.00482.001.
authors.affiliation: Department of Biochemistry , University of Cambridge , Cambridge , United Kingdom.
authors.forename: Rajika L
authors.initials: RL
authors.lastname: Perera
authors.forename: Rubben
authors.initials: R
authors.lastname: Torella
authors.forename: Sebastian
authors.initials: S
authors.lastname: Klinge
authors.forename: Mairi L
authors.initials: ML
authors.lastname: Kilkenny
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Maman
authors.forename: Luca
authors.initials: L
authors.lastname: Pellegrini
mesh_terms: D020134:Catalytic Domain; D004256:DNA Polymerase I / Q000378:metabolism*; D004271:DNA, Fungal / Q000096:biosynthesis* / Q000737:chemistry; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*
chemical_list: D004271:DNA, Fungal; D004256:DNA Polymerase I
keywords: DNA polymerase; DNA replication; Initiation of DNA synthesis; S. cerevisiae