Coding coenzyme handles: a hypothesis for the origin of the genetic code.
The coding coenzyme handle hypothesis suggests that useful coding preceded translation. Early adapters, the ancestors of present-day anticodons, were charged with amino acids acting as coenzymes of ribozymes in a metabolically complex RNA world. The ancestral aminoacyl-adapter synthetases could have been similar to present-day self-splicing tRNA introns. A codon-anticodon-discriminator base complex embedded in these synthetases could have played an important role in amino acid recognition. Extension of the genetic code proceeded through the take-over of nonsense codons by novel amino acids, related to already coded ones either through precursor-product relationship or physicochemical similarity. The hypothesis is open for experimental tests.
Szathmáry
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Institute for Advanced Study Berlin, Germany.
D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism; D005075:Biological Evolution; D003067:Coenzymes / Q000378:metabolism*; D005815:Genetic Code; D007438:Introns; D008957:Models, Genetic; D016337:RNA, Catalytic / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D003067:Coenzymes; D016337:RNA, Catalytic; D012343:RNA, Transfer; D000604:Amino Acyl-tRNA Synthetases