The Unusual X-Form DNA in Oligodeoxynucleotides: Dependence of Stability on the Base Sequence and Length
| Autor: | Luboš Arnold, Michaela Vorlíčková, Jana Chládková, Janos Sagi, Jaroslav Kypr, Attila Szemzo |
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| Rok vydání: | 1996 |
| Předmět: |
Models
Molecular Purine Base Sequence Pyrimidine Stereochemistry Circular Dichroism Temperature DNA General Medicine Molecular biology Structure-Activity Relationship chemistry.chemical_compound Pyrimidines Oligodeoxyribonucleotides Tandem repeat chemistry Purines Structural Biology Duplex (building) Pribnow box Nucleic Acid Conformation Base sequence Molecular Biology Conformational isomerism |
| Zdroj: | Journal of Biomolecular Structure and Dynamics. 13:999-1006 |
| ISSN: | 1538-0254 0739-1102 |
| DOI: | 10.1080/07391102.1996.10508914 |
| Popis: | X-form is an unusual double helix of DNA adopted by poly(dA-dT) or (dT-dA)4 at high concentrations of CsF. On the other hand, poly(dA), poly(dT), (dA-dT)4 and most other DNAs do not adopt this conformer. Here we demonstrate that the X-form is strongly destabilized by GC pairs or even minute perturbations of the alternating pyrimidinepurine sequence. For example, the 30-mer d(TATAAT)5, containing five tandem repeats of the Pribnow box, fails to isomerize into the X-form. After (dT-dA)4, the 16-mer (dT-dA)8 is shown to be the second most predisposed oligodeoxynucleotide in the (dT-dA)n series to isomerize into the X-form while the duplex lengths corresponding to n = 3,5,6,7,9,12 and 20 make the X-form unstable even in the strictly alternating (dT-dA)n sequence. Consequently, the (dT-dA)n duplex length is also a crucial factor of the X-form stability on the oligodeoxynucleotide level. We discuss a possibility that the X-form is a solution counterpart of the D-form adopted in dehydrated poly(dA-dT) fibers because properties of these two conformers are remarkably similar in many respects. |
| Databáze: | OpenAIRE |
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