Sequence context effects on 8-methoxypsoralen photobinding to defined DNA fragments

Journal Article · Tue Jun 16 00:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00386a010· OSTI ID:6176713

Sage, E; Moustacchi, E

The photoreaction of 8-methoxypsoralen (8-MOP) with DNA fragments of defined sequence was studied. The authors took advantage of the blockage by bulky adducts of the 3'-5'-exonuclease activity associated with the T4 DNA polymerase. The action of the exonuclease is stopped by biadducts as well as by monoadducts. The termination products were analyzed on sequencing gels. A strong sequence specificity was observed in the DNA photobinding of 8-MOP. The exonuclease terminates its digestion near thymine residues, mainly at potentially cross-linkable sites. There is an increasing reactivity of thymine residues in the order T < TT << TTT in a GC environment. For thymine residues in cross-linkable sites, the reactivity follows the order AT << TA approx. TAT << ATA < ATAT < ATATAA. Repeated A-T sequences are hot spots for the photochemical reaction of 8-MOP with DNA. Both monoadducts and interstrand cross-links are formed preferentially in 5'-TpA sites. The results highlight the role of the sequence and consequently of the conformation around a potential site in the photobinding of 8-MOP to DNA.

• Research Organization: Institut Curie, Biologie, Paris, France
• OSTI ID: 6176713
• Journal Information: Biochemistry; (United States), Vol. 26:12
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
DNA
BIOLOGICAL RADIATION EFFECTS
CROSS-LINKING
DNA POLYMERASES
DNA SEQUENCING
DOSE-RESPONSE RELATIONSHIPS
EXTREME ULTRAVIOLET RADIATION
GLUTATHIONE
PHOSPHORUS 32
PSORALEN
THIOUREA
THYMINE
ANTICOAGULANTS
ANTITHYROID DRUGS
AZINES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
CARBONIC ACID DERIVATIVES
CHEMICAL REACTIONS
COUMARINS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTROMAGNETIC RADIATION
ENZYMES
HEMATOLOGIC AGENTS
HETEROCYCLIC COMPOUNDS
HORMONE ANTAGONISTS
HYDROXY COMPOUNDS
ISOTOPES
LIGHT NUCLEI
NUCLEI
NUCLEIC ACIDS
NUCLEOTIDYLTRANSFERASES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PEPTIDES
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
POLYMERIZATION
POLYPEPTIDES
PROTEINS
PYRIMIDINES
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
STRUCTURAL CHEMICAL ANALYSIS
THIOUREAS
TRANSFERASES
ULTRAVIOLET RADIATION
URACILS
560120* - Radiation Effects on Biochemicals
Cells
&amp; Tissue Culture