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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
|
| pubmed:dateCreated |
1995-9-11
|
| pubmed:abstractText |
The relative biological importance of cis--syn cyclobutane dimer and pyrimidine(6-4)pyrimidone photoadduct ([6-4] photoadduct) appears to be dependent on the biological species, dipyrimidine sites and local conformational variation induced at the damaged sites. The single-strained deoxynucleotide 10-mers containing the site-specific (6-4) adduct or cis--syn cyclobutane dimer of thymidylyl(3'-->5')-thymidine were generated by direct photolysis of d(CGCATTACGC) with UVC (220-260 nm) irradiation or UVB (260-320 nm) photosensitization. Three-dimensional structures of the duplex cis--syn and (6-4) decamers of d(CGCATTACGC)xd(GCGTAATGCG) were determined by NMR spectroscopy and the relaxation matrix refinement method. The NMR data and structural calculations establish that Watson-Crick base pairing is still intact at the cis--syn dimer site while the hydrogen bonding is absent at the 3'-side of the (6-4) lesion where the T-->C transition mutation is predominantly targeted. Overall conformation of the duplex cis--syn decamer was B-DNA and produced a 9 degree bending in the DNA helix, but a distinctive base orientation of the (6-4) lesion provided a structural basis leading to 44 degree helical bending. The observed local structure and conformational rigidity at the (6-4) adduct of the thymidylyl(3'-5')-thymidine (T-T [6-4]) lesion site suggest the potential absence of hydrogen bonding at the 3' sides of the (6-4) lesion with a substituted nucleotide during replication under SOS conditions. Contrasting structural distortions induced ny the T-T (6-4) adduct with respect to the T-T cis--syn cyclobutane pyrimidine photodimer may explain the large differences in mutation spectrum and repair activities between them.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jul
|
| pubmed:issn |
0031-8655
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
62
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
44-50
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:7638271-Base Sequence,
pubmed-meshheading:7638271-DNA Adducts,
pubmed-meshheading:7638271-DNA Repair,
pubmed-meshheading:7638271-Magnetic Resonance Spectroscopy,
pubmed-meshheading:7638271-Molecular Sequence Data,
pubmed-meshheading:7638271-Molecular Structure,
pubmed-meshheading:7638271-Mutagenesis,
pubmed-meshheading:7638271-Nucleic Acid Conformation,
pubmed-meshheading:7638271-Pyrimidine Dimers
|
| pubmed:year |
1995
|
| pubmed:articleTitle |
Contrasting structural impacts induced by cis-syn cyclobutane dimer and (6-4) adduct in DNA duplex decamers: implication in mutagenesis and repair activity.
|
| pubmed:affiliation |
Department of Chemistry, Korea Advanced Institute of Science and Technology, Taejon.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|