Phased psoralen cross-links do not bend the DNA double helix
Although the chemical reaction of psoralens with nucleic acids is well understood, the structure of psoralen-DNA cross-linked products is still not clear. Model building studies based on the crystal structure of the psoralen-thymine monoadduct suggest that each cross-link bends the DNA double helix by 46.5/sup 0/. Here the authors use gel electrophoresis to test the validity of the current models. They have synthesized a series of DNA fragments (21-24 base pairs in length), each containing one unique T-A site for 4'-(hydroxymethyl)-4,5'8-trimethylpsoralen (HMT) cross-linking. Because of an estimated 28/sup 0/ unwinding of the helix by HMT, one expects that the 22-bp cross-linked fragment will be repeated nearly in phase with the average helical screw when multimerized. In that sequence ligation will maximally amplify any deformation to the double helix. They find that the ligated multimers of cross-linked DNA migrate close to the multimers of non-cross-linked DNA on polyacrylamide gels. These observations place an upper limit of 10/sup 0/ on DNA bending induced by psoralen cross-linking and indicate unwinding by about 1 bp, as well as stiffening of the double helix. These properties are not unexpected for classical intercalators.
- Research Organization:
- Yale Univ., New Haven, CT (USA)
- OSTI ID:
- 6466812
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 27:18; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Wavelength dependence for the photoreactions of DNA-psoralen monoadducts. 2. Photo-cross-linking of monoadducts
DNA structural reorganization upon conversion of a psoralen furan-side monoadduct to an interstrand cross-link: Implications for DNA repair
Related Subjects
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANTICOAGULANTS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CONFORMATIONAL CHANGES
COUMARINS
CROSS-LINKING
DNA
DRUGS
ELECTROMAGNETIC RADIATION
ELECTROPHORESIS
HEMATOLOGIC AGENTS
HETEROCYCLIC COMPOUNDS
MOLECULAR STRUCTURE
NEAR ULTRAVIOLET RADIATION
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
POLYMERIZATION
PSORALEN
RADIATION EFFECTS
RADIATIONS
ULTRAVIOLET RADIATION