Despite decades of research, several physico-chemical features of nucleic acids–genetic life's repository–remain a mystery. Thus, DNA solutions appear to include different quantities of double and single-stranded forms, with melting tests indicating that temperature has no influence on the composition. As a result, existing estimations of the thermodynamic stability of the base pairs are questioned. A kinetic examination of the action of DNA polymerase, microscopic reversibility revealing that polymerase action is kinetically regulated, whereas proof reading-excision is thermodynamically controlled, demonstrates the Watson-Crick model's overwhelming stability.
The structural foundation for the different roles of DNA and RNA in the maintenance and proliferation of life is likewise unknown. The 2' ribose hydroxyl group appears to sterically restrict the creation of the RNA double helix, which is also relatively inaccessible to external base, improving hydrolytic stability. The needs of RNA's assigned biological purpose are expected to dictate its in vivo shape, with the big size of tRNAs being particularly important in perhaps leading to greater specificity in its interaction with the matching tRNA synthetase. The fact that RNA tends to stay single-stranded in general might explain why viruses persist as stable RNA-protein complexes.The fact that the translation of the genetic code is dependent on the action of multiple tRNA synthetases blurs nucleic acids' primary function as "genetic guardians." This means that codon-anticodon specificity is only exhibited by the participation of protein molecules that are unique to each codon-anticodon pair. This has fascinating implications for the genesis and development of the genetic code, implying that tRNA synthetases are a remnant of primordial protein-nucleic acid hybrids (thus also raising doubts about the RNA world hypothesis).
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