title: The essential C family DnaE polymerase is error-prone and efficient at lesion bypass.
abstract: DnaE-type DNA polymerases belong to the C family of DNA polymerases and are responsible for chromosomal replication in prokaryotes. Like most closely related Gram-positive cells, Streptococcus pyogenes has two DnaE homologs Pol C and DnaE; both are essential to cell viability. Pol C is an established replicative polymerase, and DnaE has been proposed to serve a replicative role. In this report, we characterize S. pyogenes DnaE polymerase and find that it is highly error-prone. DnaE can bypass coding and noncoding lesions with high efficiency. Error-prone extension is accomplished by either of two pathways, template-primer misalignment or direct primer extension. The bypass of abasic sites is accomplished mainly through "dNTP-stabilized" misalignment of template, thereby generating (-1) deletions in the newly synthesized strand. This mechanism may be similar to the dNTP-stabilized misalignment mechanism used by the Y family of DNA polymerases and is the first example of lesion bypass and error-prone synthesis catalyzed by a C family polymerase. Thus, DnaE may function in an error-prone capacity that may be essential in Gram-positive cells but not Gram-negative cells, suggesting a fundamental difference in DNA metabolism between these two classes of bacteria.
authors.affiliation: The Rockefeller University, New York, New York 10021, USA. bruck@mod.rockefeller.edu
authors.forename: Irina
authors.initials: I
authors.lastname: Bruck
authors.forename: Myron F
authors.initials: MF
authors.lastname: Goodman
authors.forename: Mike
authors.initials: M
authors.lastname: O'Donnell
mesh_terms: D015075:2-Aminopurine / Q000378:metabolism; D000080242:8-Hydroxy-2'-Deoxyguanosine; D020137:Base Pair Mismatch; D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D004258:DNA Polymerase III / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D009841:Oligonucleotides / Q000378:metabolism; D013297:Streptococcus pyogenes / Q000201:enzymology*; D013379:Substrate Specificity; D013698:Templates, Genetic; D013942:Thymine Nucleotides / Q000378:metabolism
chemical_list: D017931:DNA Primers; D029968:Escherichia coli Proteins; D009841:Oligonucleotides; D013942:Thymine Nucleotides; D015075:2-Aminopurine; D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; C074904:DNA polymerase III, alpha subunit; D004258:DNA Polymerase III; C468316:dnaQ protein, E coli; D003849:Deoxyguanosine; C024157:thymidine 5'-triphosphate