Cytosine photoproduct-DNA glycosylase in Escherichia coli and cultured human cells
- Temple Univ. School of Medicine, Philadelphia, PA (USA)
Ultraviolet irradiation of DNA produces a variety of pyrimidine base damages. The activities of Escherichia coli endonuclease III and a human lymphoblast endonuclease that incises ultraviolet-irradiated DNA at modified cytosine moieties were compared. Both the bacterial and human enzymes release this cytosine photoproduct as a free base. These glycosylase activities are linear with times of reaction, quantities of enzyme, and irradiation dosages of the substrates. Both enzyme activities are similarly inhibited by the addition of monovalent and divalent cations. Analysis by DNA sequencing identified loci of endonucleolytic incision as cytosines. These are neither cyclobutane pyrimidine dimers, 6-(1,2-dihydro-2-oxo-4-pyrimidinyl)-5-methyl-2,4(1H,3H)-pyrimidinediones, nor apyrimidinic sites. This cytosine photoproduct is separable from unmodified cytosine by high-performance liquid chromatography. This separation should facilitate identification of this modified cytosine and elucidation of its biological significance.
- OSTI ID:
- 5646964
- Journal Information:
- Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 28:4; ISSN 0006-2960; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINES
ANIMAL CELLS
ATP
AZINES
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BIOLOGICAL RADIATION EFFECTS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARBON 14 COMPOUNDS
CELL CULTURES
CONNECTIVE TISSUE CELLS
CYTOSINE
DAYS LIVING RADIOISOTOPES
DNA
DNA SEQUENCING
DNA-ASE
ELECTROMAGNETIC RADIATION
ENDONUCLEASES
ENZYME ACTIVITY
ENZYMES
ESCHERICHIA COLI
ESTERASES
EXTREME ULTRAVIOLET RADIATION
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROLASES
ISOTOPES
LABELLED COMPOUNDS
LEUKOCYTES
LIGHT NUCLEI
LYMPHOCYTES
MATERIALS
MICROORGANISMS
NUCLEI
NUCLEIC ACIDS
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOSPHODIESTERASES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PYRIMIDINE DIMERS
PYRIMIDINES
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
RADIOISOTOPES
RECOMBINANT DNA
SOMATIC CELLS
STRUCTURAL CHEMICAL ANALYSIS
SUBSTRATES
TRITIUM COMPOUNDS
ULTRAVIOLET RADIATION