title: Single-molecule studies reveal the function of a third polymerase in the replisome.
abstract: The Escherichia coli replisome contains three polymerases, one more than necessary to duplicate the two parental strands. Using single-molecule studies, we reveal two advantages conferred by the third polymerase. First, dipolymerase replisomes are inefficient at synthesizing lagging strands, leaving single-strand gaps, whereas tripolymerase replisomes fill strands almost to completion. Second, tripolymerase replisomes are much more processive than dipolymerase replisomes. These features account for the unexpected three-polymerase-structure of bacterial replisomes.
authors.affiliation: The Rockefeller University, Howard Hughes Medical Institute, New York, New York, USA.
authors.forename: Roxana E
authors.initials: RE
authors.lastname: Georgescu
authors.forename: Isabel
authors.initials: I
authors.lastname: Kurth
authors.forename: Mike E
authors.initials: ME
authors.lastname: O'Donnell
mesh_terms: D004258:DNA Polymerase III / Q000737:chemistry / Q000378:metabolism*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D008957:Models, Genetic; D008958:Models, Molecular; D009097:Multienzyme Complexes / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; C074904:DNA polymerase III, alpha subunit; D004258:DNA Polymerase III; C468316:dnaQ protein, E coli