Metabolic origin of the fused aminoacyl-tRNA synthetase, glutamyl-prolyl-tRNA synthetase

Eswarappa, Sandeep M and Potdar, Alka A and Sahoo, Sarthak and Sankar, Santhosh and Fox, Paul L (2018) Metabolic origin of the fused aminoacyl-tRNA synthetase, glutamyl-prolyl-tRNA synthetase. In: JOURNAL OF BIOLOGICAL CHEMISTRY, 293 (49). pp. 19148-19156.

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Abstract

About 1 billion years ago, in a single-celled holozoan ancestor of all animals, a gene fusion of two tRNA synthetases formed the bifunctional enzyme, glutamyl-prolyl-tRNA synthetase (EPRS). We propose here that a confluence of metabolic, biochemical, and environmental factors contributed to the specific fusion of glutamyl- (ERS) and prolyl- (PRS) tRNA synthetases. To test this idea, we developed a mathematical model that centers on the precursor-product relationship of glutamic acid and proline, as well as metabolic constraints on free glutamic acid availability near the time of the fusion event. Our findings indicate that proline content increased in the proteome during the emergence of animals, thereby increasing demand for free proline. Together, these constraints contributed to a marked cellular depletion of glutamic acid and its products, with potentially catastrophic consequences. In response, an ancient organism invented an elegant solution in which genes encoding ERS and PRS fused to form EPRS, forcing coexpression of the two enzymes and preventing lethal dysregulation. The substantial evolutionary advantage of this coregulatory mechanism is evidenced by the persistence of EPRS in nearly all extant animals.

Item Type:	Journal Article
Publication:	JOURNAL OF BIOLOGICAL CHEMISTRY
Publisher:	AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Additional Information:	Copyright for this article belongs to American Society for Biochemistry and Molecular Biology.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	09 Mar 2019 09:23
Last Modified:	09 Mar 2019 09:23
URI:	http://eprints.iisc.ac.in/id/eprint/61906

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