The Role of Unconventional Hydrogen Bonds in Determining BII Propensities in B-DNA

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• 作者：Alexandra Balaceanu ; Marco Pasi ; Pablo D. DansAdam Hospital ; Richard Lavery ; Modesto Orozco
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2017
• 出版时间：January 5, 2017
• 年：2017
• 卷：8
• 期：1
• 页码：21-28
• 全文大小：558K
• ISSN：1948-7185

文摘

An accurate understanding of DNA backbone transitions is likely to be the key for elucidating the puzzle of the intricate sequence-dependent mechanical properties that govern most of the biologically relevant functions of the double helix. One factor believed to be important in indirect recognition within protein–DNA complexes is the combined effect of two DNA backbone torsions (ε and ζ) which give rise to the well-known BI/BII conformational equilibrium. In this work we explain the sequence-dependent BII propensity observed in RpY steps (R = purine; Y = pyrimidine) at the tetranucleotide level with the help of a previously undetected C–H···O contact between atoms belonging to adjacent bases. Our results are supported by extensive multimicrosecond molecular dynamics simulations from the Ascona B-DNA Consortium, high-level quantum mechanical calculations, and data mining of the experimental structures deposited in the Protein Data Bank.