Dynamics of termination during in vitro replication of ultraviolet-irradiated DNA with DNA polymerase III holoenzyme of Escherichia coli

Journal Article · Wed Aug 05 04:00:00 EDT 1987 · J. Biol. Chem.; (United States)

OSTI ID:6122594

Shwartz, H; Livneh, Z

During in vitro replication of UV-irradiated single-stranded DNA with Escherichia coli DNA polymerase III holoenzyme termination frequently occurs at pyrimidine photodimers. The termination stage is dynamic and characterized by at least three different events: repeated dissociation-reinitiation cycles of the polymerase at the blocked termini; extensive hydrolysis of ATP to ADP and inorganic phosphate; turnover of dNTPs into dNMP. The reinitiation events are nonproductive and are not followed by further elongation. The turnover of dNTPs into dNMPs is likely to result from repeated cycles of insertion of dNMP residues opposite the blocking lesions followed by their excision by the 3'----5' exonucleolytic activity of the polymerase. Although all dNTPs are turned over, there is a preference for dATP, indicating that DNA polymerase III holoenzyme has a preference for inserting a dAMP residue opposite blocking pyrimidine photodimers. We suggest that the inability of the polymerase to bypass photodimers during termination is due to the formation of defective initiation-like complexes with reduced stability at the blocked termini.

• Research Organization: Weizmann Institute of Science, Rehovot, Israel
• OSTI ID: 6122594
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 262:22; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

560120* -- Radiation Effects on Biochemicals
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ATP
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CHEMICAL REACTIONS
DECOMPOSITION
DNA
DNA POLYMERASES
DNA REPLICATION
ELECTROMAGNETIC RADIATION
ENZYME ACTIVITY
ENZYMES
ESCHERICHIA COLI
GENETIC EFFECTS
GENETIC RADIATION EFFECTS
HYDROLYSIS
IN VITRO
LYSIS
MICROORGANISMS
NUCLEIC ACID REPLICATION
NUCLEIC ACIDS
NUCLEOTIDES
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
PYRIMIDINE DIMERS
RADIATION EFFECTS
RADIATIONS
SOLVOLYSIS
TRANSFERASES
ULTRAVIOLET RADIATION