An NMR study of the conformation and thermodynamics of the circular dumbbell d [formula: see text] Slow exchange between two- and four-membered hairpin loops. |
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| Authors: | J H Ippel V Lanzotti A Galeone L Mayol J E van den Boogaart J A Pikkemaat C Altona |
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| Institution: | Department of Organic Chemistry, Leiden University, The Netherlands. |
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| Abstract: | The circular DNA decamer 5'-d formula: see text] 3' is studied in solution by means of NMR spectroscopy. At low temperature the molecule adopts a dumbbell structure with three Watson-Crick C-G base pairs and two two-residue loops in opposite parts of the molecule. On raising the temperature another conformer appears, in which the closing C-G base pair in the 5'-GTTC-3' loop is disrupted, whereas the opposite 5'-CTTG-3' loop remains stable. The two conformers are in slow equilibrium over a limited temperature range. |
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