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Conformational fluctuations in single DNA molecules.

S Wennmalm·L Edman·R Rigler
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Abstract

Measurement of fluorescent lifetimes of dye-tagged DNA molecules reveal the existence of different conformations. Conformational fluctuations observed by fluorescence correlation spectroscopy give rise to a relaxation behavior that is described by "stretched" exponentials and indicates the presence of a distribution of transition rates between two conformations. Whether this is an inhomogeneous distribution, where each molecule contributes with its own reaction rate to the overall distribution, or a homogeneous distribution, where the reaction rate of each molecule is time-dependent, is not yet known. We used a tetramethylrhodamine-linked 217-bp DNA oligonucleotide as a probe for conformational fluctuations. Fluorescence fluctuations from single DNA molecules attached to a streptavidin-coated surface directly show the transitions between two conformational states. The conformational fluctuations typical for single molecules are similar to those seen in single ion channels in cell membranes.

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DNAModels, ChemicalNucleic Acid ConformationSpectrometry, FluorescenceJournal ArticleResearch Support, Non-U.S. Gov't

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S Wennmalm, L Edman, R Rigler. 1997-09-30. Conformational fluctuations in single DNA molecules.. https://doi.org/10.1073/pnas.94.20.10641

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