Error Propagation in Translation and its Relevance to the Nucleation of Life
Some of the enzymes produced by the translation of information stored in nucleic acid sequences participate as adaptors in the translation processes itself. The more errors there are in the adaptors doing the translation, the lower the quality (and therefore the lower the accuracy in action) of the adaptors that are produced. Conceivably the level of errors could escalate to give an “error catastrophe” [Orgel, 1963]. A mathematical model of this process has been formulated, based on a simple “all-or-none” classification of the amino acid residues of a typical adaptor residue [Hoffmann, 1974, 1975]. The model permits an estimate to be made of the threshold level of specificity, required by the components of a workable primitive translation apparatus. In the model, a certain number of the amino acid residues of an adaptor are presumed to be critical for the correct folding of the adaptor, (such that if an error is made there, all activity is lost), and a certain number are presumed to be critical for the specificity of adaptors (such that an error made in those sites results in an adaptor that makes correct each of the possible incorrect assignments with equal rates). The remaining amino acid residues are assumed to function as spacers, so that errors in those sites are without consequence for the functioning and specificity of the adaptors, as a function of the accuracy in action qi-1 of the preceding generation.
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