Isolation of an altered form of DNA polymerase I from Escherichia coli cells induced for recA/lexA functions
A novel form of DNA polymerase I (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, DNA nucleotidyltransferase, EC 2.7.7.7) activity has been isolated from Escherichia coli cells that had been activated for expression of the DNA damage-inducible genes. Induction was by treatment of normal cells or cells carrying the spr-51 and tif-1 mutations with nalidixic acid. This activity, DNA polymerase I*, seems to be a form of DNA polymerase I because it is insensitive to N-ethyllmaleimide, is inhibited by antibody to DNA polymerase I, and does not appear in a polA1 strain. DNA polymerase I* activity sediments through sucrose gradients as a broad peak with S/sub 20//sub ,w/ = 6.6-10.5, compared with an S/sub 20//sub,w/ = 4.8-5.5 for DNA polymerase I. The fidelity during polymerization reactions of DNA polymerase I* is relatively low with a variety of synthetic templates and deoxynucleosidetriphosphates, although the enzyme appears to have a normal level of 3'->5' exonuclease. Polymerase I* has properties that might implicate it in some form of mutagenic DNA repair.
- Research Organization:
- Univ. of California, Berkeley, CA (United States)
- OSTI ID:
- 5527712
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 79:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
POLYMERASES
CHEMICAL ACTIVATION
CHEMICAL ANALYSIS
BIOLOGICAL REPAIR
DNA
ENZYME ACTIVITY
ESCHERICHIA COLI
GENES
MUTAGENESIS
BACTERIA
BIOLOGICAL RECOVERY
ENZYMES
MICROORGANISMS
NUCLEIC ACIDS
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
RECOVERY
REPAIR
TRANSFERASES
550200* - Biochemistry