Studies On The Cross Strand Hydrogen Bonds In DNA Double Helices |
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Authors: | S. Mohan N. Yathindra |
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Affiliation: | Department of Crystallography and Biophysics , University of Madras , Guindy Campus, Madras , 600 025 , India |
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Abstract: | Abstract A systematic analysis has been carried out to examine all the stereochemically possible bifurcated hydrogen bonds including those of cross strand type between propeller twisted base pairs in DNA double helices by stereochemical considerations involving base pairs alone and by molecular mechanics studies on dimer and trimer duplexes. The results show that there are limited number of combinations of adjacent base pairs that would facilitate bifurcated cross- strand hydrogen bond (CSH). B-type helices concomitant with negative propeller twist seem to be more favored for the occurrence of CSH than canonical A-type helices because of slide in the latter. The results also demonstrate that helices with appropriate sequences may possess continuous run of these propeller twist driven cross strand hydrogen bonds indicating that they may infact be considered as yet another general structural feature of DNA helices. |
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Keywords: | protein folding hydrophobic hydrophilic effects hydrophilic forces Anfinsen’s hypothesis Levinthal’s question |
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