Balasubramanian R, Seetharamulu P. A conformational rationale for the replication of nucleic acids under prebiotic conditions.
Biosystems 1984;
17:77-85. [PMID:
6525457 DOI:
10.1016/0303-2647(84)90002-9]
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Abstract
The Watson-Crick model at once gave an explanation for the mechanism of replication of DNA. But the hydrogen-bonding forces between the bases alone are not enough for the specificity of base-pairing mechanisms, since any pair of bases can be positioned to have at least two hydrogen bonds. In the present-day biological organisms, sophisticated enzymatic machinery is supposed to constrain the ribose-phosphate backbone to have regular structure, aiding the self-templating duplication. For the prebiotic stage, whence sophisticated enzymes would not have been evolved, we propose a novel double helical conformation of DNA wherein the two sugar-phosphate backbones are pulled towards each other by (C-H - -O) hydrogen bonds conferring stereospecificity for the formation of (A:T)- and (G:C)-pairs, in the self-templating chains of DNA. Our model-building efforts and computer calculations endorse the stereochemical feasibility of the conformation. The pairing of homologous sequences of two double helices of DNA is explained by direct hydrogen-bonding interactions in our model and it is thus relevant to the present-day biological functions also, at least in some stages of the cell-cycle.
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