A speculation on the origin of protein synthesis

  title={A speculation on the origin of protein synthesis},
  author={Francis H. C. Crick and Sydney Brenner and Aaron Klug and George Pieczenik},
  journal={Origins of life},
It is suggested that protein synthesis may have begun without even a primitive ribosome if the primitive tRNA could take up two configurations and could bind to the messenger RNA with five base-pairs instead of the present three. This idea would impose base sequence restriction on the early messages and on the early genetic code such that the first four amino acids coded were glycine, serine, aspartic acid and aspargine. A possible mechanism is suggested for the polymerization of the early… 
Polynucleotide replication coupled to protein synthesis: A possible mechanism for the origin of life
The primitive replication-coupled system would then have been able to synthesize specific proteins containing one amino acid residue for each primitive tRNA incorporated during replication, giving rise directly to triplet-coded protein synthesis.
Transfer-RNA, an early gene?
The reconstruction of tRNA precursors yields such a molecule showing some reverberation of a codon pattern GNC that suggests that tRNA has been the earliest component of the translation machinery.
Early assignments of the genetic code dependent upon protein structure
It is shown that with the present-day code the corresponding nucleotides do have a high percentage of alternating purine/pyrimidine sequences and these combined restraints on the primitive synthetic machinery would direct the possible assignments of the genetic code helping to explain its regularity and universality.
Transfer RNA: The molecular demiurge in the origin of biological systems.
Single nucleotide translation without ribosomes
It has been shown that aminoacylated nucleotides couple to amino-acid-bearing oligoribonucleotides, directed by an RNA template, forming specific di- and tripeptides in the absence of ribosomal machinery.
The transorientation hypothesis for codon recognition during protein synthesis
A molecular mechanism for the decoding phase of translation: the transorientation hypothesis is proposed, which incorporates a newly identified tRNA binding site and utilizes a flip between two tRNA anticodon loop structures, the 5′-stacked and the 3′-Stacked conformations.
Aminoacyl-tRNA synthetase families and their significance to the origin of the genetic code
Strong correlations in the enzyme family of Ile-, Phe-, Val-, Met-, and Leu-tRNA synthetases suggests that these enzymes evolved last, and that an earlier version of the Genetic Code was comprised solely of codons containing a central purine.
A conformational rationale for the origin of the mechanism of nucleicacid-directed protein synthesis of ‘living’ organisms
The nucleicacid-directed protein synthesis is shown to be a natural consequence of a particular way of favourable interaction between nucleic acids and amino acids, and the model provides the missing link between the chemical evolution of small organic molecules and biological evolution through the process of mutations in nucleicacids and nucleic acid-directedprotein synthesis.


Evolution of the genetic apparatus.
  • L. Orgel
  • Biology
    Journal of molecular biology
  • 1968
The Genetic Code
If one could compare the base sequence of a long piece of nucleic acid with the amino acid sequence for which it codes, the genetic code could easily be deduced, but this direct approach is not yet possible because of the technical difficulties in determining a long nucleotide sequence.
Conformation of the Anticodon Loop in tRNA
A molecular model for the anticodon arm is proposed which is compatible with chemical, X-ray and genetic evidence. It provides a stereochemical basis for Crick's “wobble” hypothesis.
Molecular Mechanics of Translation : a Reciprocating Ratchet Mechanism
A model is suggested for protein synthesis which depends upon conformational changes in tRNA and allosteric transitions in place of translocation.
  • F. Crick, J. Griffith, L. Orgel
  • Computer Science, Medicine
    Proceedings of the National Academy of Sciences of the United States of America
  • 1957