Mechanism of replication of ultraviolet-irradiated single-stranded DNA by DNA polymerase III holoenzyme of Escherichia coli. Implications for SOS mutagenesis

Journal Article · Tue Jul 15 00:00:00 EDT 1986 · J. Biol. Chem.; (United States)

OSTI ID:5092168

Livneh, Z

Replication of UV-irradiated oligodeoxynucleotide-primed single-stranded phi X174 DNA with Escherichia coli DNA polymerase III holoenzyme in the presence of single-stranded DNA-binding protein was investigated. The extent of initiation of replication on the primed single-stranded DNA was not altered by the presence of UV-induced lesions in the DNA. The elongation step exhibited similar kinetics when either unirradiated or UV-irradiated templates were used. Inhibition of the 3'----5' proofreading exonucleolytic activity of the polymerase by dGMP or by a mutD mutation did not increase bypass of pyrimidine photodimers, and neither did purified RecA protein influence the extent of photodimer bypass as judged by the fraction of full length DNA synthesized. Single-stranded DNA-binding protein stimulated bypass since in its absence the fraction of full length DNA decreased 5-fold. Termination of replication at putative pyrimidine dimers involved dissociation of the polymerase from the DNA, which could then reinitiate replication at other available primer templates. Based on these observations a model for SOS-induced UV mutagenesis is proposed.

• OSTI ID: 5092168
• Journal Information: J. Biol. Chem.; (United States), Vol. 20
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
DNA REPLICATION
BIOLOGICAL PATHWAYS
DNA POLYMERASES
ESCHERICHIA COLI
MUTAGENESIS
PYRIMIDINE DIMERS
ULTRAVIOLET RADIATION
BACTERIA
ELECTROMAGNETIC RADIATION
ENZYMES
MICROORGANISMS
NUCLEIC ACID REPLICATION
NUCLEOTIDYLTRANSFERASES
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
RADIATIONS
TRANSFERASES
560111* - Radiation Effects on Biochemicals- In Vitro- (-1987)