Conformational Flexibility of DNA

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• 作者：Andriy Marko ; Vasyl Denysenkov ; Dominik Margraf ; Pavol Cekan ; Olav Schiemann ; Snorri Th. Sigurdsson ; Thomas F. Prisner
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：August 31, 2011
• 年：2011
• 卷：133
• 期：34
• 页码：13375-13379
• 全文大小：784K
• 年卷期：v.133,no.34(August 31, 2011)
• ISSN：1520-5126

文摘

Pulsed Electron鈥揈lectron Double Resonance (PELDOR) on double-stranded DNA (ds-DNA) was used to investigate the conformational flexibility of helical DNA. Stretching, twisting, and bending flexibility of ds-DNA was determined by incorporation of two rigid nitroxide spin labels into a series of 20 base pair (bp) DNA duplexes. Orientation-selective PELDOR experiments performed at both X-band (9 GHz/0.3 T) and G-band (180 GHz/6.4 T) with spin label distances in the range of 2鈥? nm allowed us to differentiate between different simple models of DNA dynamics existing in the literature. All of our experimental results are in full agreement with a dynamic model for ds-DNA molecules, where stretching of the molecule leads to a slightly reduced radius of the helix induced by a cooperative twist鈥搒tretch coupling.