Publication Date:
2021-04-19
Description:
It has been hypothesized that early enzymes are more promiscuous than their extant orthologues. Whether or not this hypothesis applies to the translation machinery, the oldest molecular machine of life, is not known. Efficient protein synthesis relies on a cascade of specific interactions between the ribosome and the translation factors. Here, using Elongation factor-Tu (EF-Tu) as a model system, we have explored the evolution of ribosome specificity in translation factors. Employing pre-steady state fast kinetics using quench-flow, we have quantitatively characterized the specificity of two sequence-reconstructed 1.3 to 3.3-billion-year-old ancestral EF-Tus towards two unrelated bacterial ribosomes, mesophilic Escherichia coli and thermophilic Thermus thermophilus. While the modern EF-Tus show clear preference for their respective ribosomes, the ancestral EF-Tus show similar specificity for diverse ribosomes. Also, despite increase in the catalytic activity with temperature, the ribosome specificity of the thermophilic EF-Tus remain virtually unchanged. Our kinetic analysis thus suggests that EF-Tu proteins likely evolved from the catalytically promiscuous, ‘generalist’ ancestors. Furthermore, compatibility of diverse ribosomes with the modern and ancestral EF-Tus suggests that the ribosomal core probably evolved before the diversification of the EF-Tus. This study thus provides important insights regarding the evolution of modern translation machinery.
Print ISSN:
0737-4038
Electronic ISSN:
1537-1719
Topics:
Biology
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