The structure of DNA overstretched from the 5′5′ ends differs from the structure of DNA overstretched from the 3′3′ ends
| Autor: | Nancy Kleckner, Charles Limouse, Vincent W. Coljee, Kristi Hatch, Claudia Danilowicz, Alyson Conover, Mara Prentiss |
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| Rok vydání: | 2009 |
| Předmět: |
Cyclodextrins
Multidisciplinary Base pair Hydrogen bond Hydrogen Bonding DNA Glyoxal Buffers Nucleic Acid Denaturation Microspheres Force curves Biomechanical Phenomena Microsphere chemistry.chemical_compound Crystallography chemistry Physical Sciences Nucleic Acid Conformation Molecule Salts Base Pairing |
| Zdroj: | Proceedings of the National Academy of Sciences. 106:13196-13201 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.0904729106 |
| Popis: | It has been suggested that the structure that results when double-stranded DNA (dsDNA) is pulled from the 3′3′ ends differs from that which results when it is pulled from the 5′5′ ends. In this work, we demonstrate, using λ phage dsDNA, that the overstretched states do indeed show different properties, suggesting that they correspond to different structures. For 3′3′ pulling versus 5′5′ pulling, the following differences are observed: ( i ) the forces at which half of the molecules in the ensemble have made a complete force-induced transition to single stranded DNA are 141 ± 3 pN and 122 ± 4 pN, respectively; ( ii ) the extension vs. force curve for overstretched DNA has a marked change in slope at 127 ± 3 pN for 3′3′ and 110 ± 3 pN for 5′5′; ( iii ) the hysteresis (H) in the extension vs. force curves at 150 mM NaCl is 0.3 ± 0.8 pN μm for 3′3′ versus 13 ± 8 pN for 5′5′; and ( iv ) 3′3′ and 5′5′ molecules show different changes in hysteresis due to interactions with β-cyclodextrin, a molecule that is known to form stable host-guest complexes with rotated base pairs, and glyoxal that is known to bind stably to unpaired bases. These differences and additional findings are well-accommodated by the corresponding structures predicted on theoretical grounds. |
| Databáze: | OpenAIRE |
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