Document Detail

Hypothesis: emergence of translation as a result of RNA helicase evolution.
MedLine Citation:
PMID:  22544085     Owner:  NLM     Status:  MEDLINE    
The origin of translation and the genetic code is one of the major mysteries of evolution. The advantage of templated protein synthesis could have been achieved only when the translation apparatus had already become very complex. This means that the translation machinery, as we know it today, must have evolved towards some different essential function that subsequently sub-functionalised into templated protein synthesis. The hypothesis presented here proposes that translation originated as the result of evolution of a primordial RNA helicase, which has been essential for preventing dying out of the RNA organism in sterile double-stranded form. This hypothesis emerges because modern ribosome possesses RNA helicase activity that likely dates back to the RNA world. I hypothesise that codon-anticodon interactions of tRNAs with mRNA evolved as a mechanism used by RNA helicase, the predecessor of ribosomes, to melt RNA duplexes. In this scenario, peptide bond formation emerged to drive unidirectional movement of the helicase via a molecular ratchet mechanism powered by Brownian motion. I propose that protein synthesis appeared as a side product of helicase activity. The first templates for protein synthesis were functional RNAs (ribozymes) that were unwound by the helicase, and the first synthesised proteins were of random or non-sense sequence. I further suggest that genetic code emerged to avoid this randomness. The initial genetic code thus emerged as an assignment of amino acids to codons according to the sequences of the pre-existing RNAs to take advantage of the side products of RNA helicase function.
Nikolay Zenkin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-04-28
Journal Detail:
Title:  Journal of molecular evolution     Volume:  74     ISSN:  1432-1432     ISO Abbreviation:  J. Mol. Evol.     Publication Date:  2012 Jun 
Date Detail:
Created Date:  2012-07-31     Completed Date:  2013-03-18     Revised Date:  2014-03-14    
Medline Journal Info:
Nlm Unique ID:  0360051     Medline TA:  J Mol Evol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  249-56     Citation Subset:  IM    
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MeSH Terms
Evolution, Molecular*
Models, Genetic*
Nucleic Acid Conformation
Protein Biosynthesis / genetics*
RNA / genetics,  metabolism
RNA Helicases / genetics*
Grant Support
202994//European Research Council; //Biotechnology and Biological Sciences Research Council
Reg. No./Substance:
63231-63-0/RNA; EC Helicases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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