Cargando…
Functional analyses of ancestral thioredoxins provide insights into their evolutionary history
Thioredoxin (Trx) is a conserved, cytosolic reductase in all known organisms. The enzyme receives two electrons from NADPH via thioredoxin reductase (TrxR) and passes them on to multiple cellular reductases via disulfide exchange. Despite the ubiquity of thioredoxins in all taxa, little is known abo...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Biochemistry and Molecular Biology
2019
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6755812/ https://www.ncbi.nlm.nih.gov/pubmed/31366732 http://dx.doi.org/10.1074/jbc.RA119.009718 |
_version_ | 1783453298966134784 |
---|---|
author | Napolitano, Silvia Reber, Robin J. Rubini, Marina Glockshuber, Rudi |
author_facet | Napolitano, Silvia Reber, Robin J. Rubini, Marina Glockshuber, Rudi |
author_sort | Napolitano, Silvia |
collection | PubMed |
description | Thioredoxin (Trx) is a conserved, cytosolic reductase in all known organisms. The enzyme receives two electrons from NADPH via thioredoxin reductase (TrxR) and passes them on to multiple cellular reductases via disulfide exchange. Despite the ubiquity of thioredoxins in all taxa, little is known about the functions of resurrected ancestral thioredoxins in the context of a modern mesophilic organism. Here, we report on functional in vitro and in vivo analyses of seven resurrected Precambrian thioredoxins, dating back 1–4 billion years, in the Escherichia coli cytoplasm. Using synthetic gene constructs for recombinant expression of the ancestral enzymes, along with thermodynamic and kinetic assays, we show that all ancestral thioredoxins, as today's thioredoxins, exhibit strongly reducing redox potentials, suggesting that thioredoxins served as catalysts of cellular reduction reactions from the beginning of evolution, even before the oxygen catastrophe. A detailed, quantitative characterization of their interactions with the electron donor TrxR from Escherichia coli and the electron acceptor methionine sulfoxide reductase, also from E. coli, strongly hinted that thioredoxins and thioredoxin reductases co-evolved and that the promiscuity of thioredoxins toward downstream electron acceptors was maintained during evolution. In summary, our findings suggest that thioredoxins evolved high specificity for their sole electron donor TrxR while maintaining promiscuity to their multiple electron acceptors. |
format | Online Article Text |
id | pubmed-6755812 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | American Society for Biochemistry and Molecular Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-67558122019-09-24 Functional analyses of ancestral thioredoxins provide insights into their evolutionary history Napolitano, Silvia Reber, Robin J. Rubini, Marina Glockshuber, Rudi J Biol Chem Molecular Biophysics Thioredoxin (Trx) is a conserved, cytosolic reductase in all known organisms. The enzyme receives two electrons from NADPH via thioredoxin reductase (TrxR) and passes them on to multiple cellular reductases via disulfide exchange. Despite the ubiquity of thioredoxins in all taxa, little is known about the functions of resurrected ancestral thioredoxins in the context of a modern mesophilic organism. Here, we report on functional in vitro and in vivo analyses of seven resurrected Precambrian thioredoxins, dating back 1–4 billion years, in the Escherichia coli cytoplasm. Using synthetic gene constructs for recombinant expression of the ancestral enzymes, along with thermodynamic and kinetic assays, we show that all ancestral thioredoxins, as today's thioredoxins, exhibit strongly reducing redox potentials, suggesting that thioredoxins served as catalysts of cellular reduction reactions from the beginning of evolution, even before the oxygen catastrophe. A detailed, quantitative characterization of their interactions with the electron donor TrxR from Escherichia coli and the electron acceptor methionine sulfoxide reductase, also from E. coli, strongly hinted that thioredoxins and thioredoxin reductases co-evolved and that the promiscuity of thioredoxins toward downstream electron acceptors was maintained during evolution. In summary, our findings suggest that thioredoxins evolved high specificity for their sole electron donor TrxR while maintaining promiscuity to their multiple electron acceptors. American Society for Biochemistry and Molecular Biology 2019-09-20 2019-07-31 /pmc/articles/PMC6755812/ /pubmed/31366732 http://dx.doi.org/10.1074/jbc.RA119.009718 Text en © 2019 Napolitano et al. Published by The American Society for Biochemistry and Molecular Biology, Inc. Author's Choice—Final version open access under the terms of the Creative Commons CC-BY license (http://creativecommons.org/licenses/by/4.0) . |
spellingShingle | Molecular Biophysics Napolitano, Silvia Reber, Robin J. Rubini, Marina Glockshuber, Rudi Functional analyses of ancestral thioredoxins provide insights into their evolutionary history |
title | Functional analyses of ancestral thioredoxins provide insights into their evolutionary history |
title_full | Functional analyses of ancestral thioredoxins provide insights into their evolutionary history |
title_fullStr | Functional analyses of ancestral thioredoxins provide insights into their evolutionary history |
title_full_unstemmed | Functional analyses of ancestral thioredoxins provide insights into their evolutionary history |
title_short | Functional analyses of ancestral thioredoxins provide insights into their evolutionary history |
title_sort | functional analyses of ancestral thioredoxins provide insights into their evolutionary history |
topic | Molecular Biophysics |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6755812/ https://www.ncbi.nlm.nih.gov/pubmed/31366732 http://dx.doi.org/10.1074/jbc.RA119.009718 |
work_keys_str_mv | AT napolitanosilvia functionalanalysesofancestralthioredoxinsprovideinsightsintotheirevolutionaryhistory AT reberrobinj functionalanalysesofancestralthioredoxinsprovideinsightsintotheirevolutionaryhistory AT rubinimarina functionalanalysesofancestralthioredoxinsprovideinsightsintotheirevolutionaryhistory AT glockshuberrudi functionalanalysesofancestralthioredoxinsprovideinsightsintotheirevolutionaryhistory |