Minireview: excision repair of DNA base damage. [Gamma radiation, Escherichia coli]

Journal Article · Wed May 01 04:00:00 EDT 1974 · Life Sci.; (United States)

DOI:https://doi.org/10.1016/0024-3205(74)90322-1· OSTI ID:7216549

Cerutti, P A

Exposure of cells to exogenous physical and chemical agents can result in damage to the DNA bases. DNA damage can lead to mutation, malignant transformation and cell death and may possibly be involved in cellular aging. Structurally related base modifications are expected to have similar biological effects regardless of the agent responsible for their formation. The biological effects may be a consequence of the local distortion of the DNA conformation by the lesion rather than of the chemical properties of the modified base per se. It may be useful, therefore, to classify DNA base damage according to its effect on DNA conformation. Several ''repair endonucleases'' have been characterized from bacteria while the search for the corresponding mammalian enzymes is only beginning. The second, probably less specific step, is the exonucleolytic degradation of the damaged portion of the DNA leading to the removal of the damaged residue. In E. coli the removal of both cyclobutane-type photodimers and ..gamma..-ray products of the 5,6-dihydroxy-dihydrothymine type is accomplished by the 5' ..-->.. 3' exonuclease associated with polymerase I. All three E. coli polymerases appear to participate in the rebuilding of the degraded portion of the DNA. Studies on the corresponding enzymes in mammalian cells have been initiated. The last step of excision repair involves the sealing of a phosphodiester bond of the DNA backbone and is accomplished by the enzyme polynucleotide ligase in bacterial and mammalian cells.

• Research Organization: Univ. of Florida, Gainesville
• OSTI ID: 7216549
• Journal Information: Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 15:9; ISSN LIFSA
• Country of Publication: United States
• Language: English

Related Subjects

560111 -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
560131* -- Radiation Effects on Microorganisms-- Basic Studies-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
BASES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
DNA
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
GAMMA RADIATION
INJURIES
IONIZING RADIATIONS
MICROORGANISMS
MUTATIONS
NUCLEASES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PHOSPHOTRANSFERASES
POLYMERASES
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
TRANSFERASES