Enzymatic activities in ultraviolet-induced DNA degradation in Escherichia coli. [Genetic variations in activity of exonucleases and polymerases in E coli mutants]
Ultraviolet-induced DNA degradation is found to occur in Escherichia coli WP6 polA1 and K-12 RS polA exl strains with the former strain degrading its DNA more extensively after 20 J/m/sup 2/. K-12 SR78 recB21 degrades very little or no DNA after 20 J/m/sup 2/. At a higher fluence of 60 J/m/sup 2/, however, about 20% of the DNA is degraded, albeit at a lower rate compared to the wild-type DY998. These data suggest that uvrA-dependent degradation involves the 5' ..-->.. 3' exonuclease activity of polymerase I (exonuclease VI) and recBC exonuclease V activity, with the latter less crucial after exposure to a larger fluence. In WP67 uvrA polA1 strains, uv-induced DNA degradation after 10 J/m/sup 2/ is abolished unless the cells are incubated in the presence of chloramphenicol. In K-12 DM20 uvrA recB21 strains, post-uv incubation after 10 J/m/sup 2/ with or without chloramphenicol does not result in DNA degradation, suggesting that chloramphenicol-enhancible degradation involves primarily recBC exonuclease activity.
- Research Organization:
- Indiana Univ., Indianapolis
- OSTI ID:
- 6355190
- Journal Information:
- Radiat. Res.; (United States), Vol. 77:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
DNA degradation in minicells of Escherichia coli K-12. II. Effect of recA1 and recB21 mutations on DNA degradation in minicells and detection of exonuclease V activity
Characterization of an Escherichia coli mutant (radB101) sensitive to. gamma. and uv radiation, and methyl methanesulfonate
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BIOLOGICAL REPAIR
BIOCHEMICAL REACTION KINETICS
DNA
RADIOLYSIS
STRAND BREAKS
ENZYME ACTIVITY
GENETIC VARIABILITY
NUCLEASES
POLYMERASES
BIOLOGICAL RADIATION EFFECTS
ESCHERICHIA COLI
EXPERIMENTAL DATA
IRRADIATION
ISOLATED VALUES
MUTANTS
ULTRAVIOLET RADIATION
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL VARIABILITY
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DATA FORMS
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ENZYMES
INFORMATION
KINETICS
MICROORGANISMS
NUCLEIC ACIDS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHOSPHOTRANSFERASES
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
REACTION KINETICS
RECOVERY
REPAIR
TRANSFERASES
560112* - Radiation Effects on Biochemicals- In Microorganisms- (-1987)
560131 - Radiation Effects on Microorganisms- Basic Studies- (-1987)
550200 - Biochemistry