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Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria

Mitochondria play a key role in the biosynthesis of two metal cofactors, iron–sulfur (FeS) clusters and molybdenum cofactor (Moco). The two pathways intersect at several points, but a scarcity of mutants has hindered studies to better understand these links. We screened a collection of sirtinol-resi...

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Autores principales: Kruse, Inga, Maclean, Andrew E., Hill, Lionel, Balk, Janneke
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Portland Press Ltd. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5791162/
https://www.ncbi.nlm.nih.gov/pubmed/29247140
http://dx.doi.org/10.1042/BCJ20170559
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author Kruse, Inga
Maclean, Andrew E.
Hill, Lionel
Balk, Janneke
author_facet Kruse, Inga
Maclean, Andrew E.
Hill, Lionel
Balk, Janneke
author_sort Kruse, Inga
collection PubMed
description Mitochondria play a key role in the biosynthesis of two metal cofactors, iron–sulfur (FeS) clusters and molybdenum cofactor (Moco). The two pathways intersect at several points, but a scarcity of mutants has hindered studies to better understand these links. We screened a collection of sirtinol-resistant Arabidopsis thaliana mutants for lines with decreased activities of cytosolic FeS enzymes and Moco enzymes. We identified a new mutant allele of ATM3 (ABC transporter of the mitochondria 3), encoding the ATP-binding cassette transporter of the mitochondria 3 (systematic name ABCB25), confirming the previously reported role of ATM3 in both FeS cluster and Moco biosynthesis. We also identified a mutant allele in CNX2, cofactor of nitrate reductase and xanthine dehydrogenase 2, encoding GTP 3′,8-cyclase, the first step in Moco biosynthesis which is localized in the mitochondria. A single-nucleotide polymorphism in cnx2-2 leads to substitution of Arg88 with Gln in the N-terminal FeS cluster-binding motif. cnx2-2 plants are small and chlorotic, with severely decreased Moco enzyme activities, but they performed better than a cnx2-1 knockout mutant, which could only survive with ammonia as a nitrogen source. Measurement of cyclic pyranopterin monophosphate (cPMP) levels by LC–MS/MS showed that this Moco intermediate was below the limit of detection in both cnx2-1 and cnx2-2, and accumulated more than 10-fold in seedlings mutated in the downstream gene CNX5. Interestingly, atm3-1 mutants had less cPMP than wild type, correlating with previous reports of a similar decrease in nitrate reductase activity. Taken together, our data functionally characterize CNX2 and suggest that ATM3 is indirectly required for cPMP synthesis.
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spelling pubmed-57911622018-02-13 Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria Kruse, Inga Maclean, Andrew E. Hill, Lionel Balk, Janneke Biochem J Research Articles Mitochondria play a key role in the biosynthesis of two metal cofactors, iron–sulfur (FeS) clusters and molybdenum cofactor (Moco). The two pathways intersect at several points, but a scarcity of mutants has hindered studies to better understand these links. We screened a collection of sirtinol-resistant Arabidopsis thaliana mutants for lines with decreased activities of cytosolic FeS enzymes and Moco enzymes. We identified a new mutant allele of ATM3 (ABC transporter of the mitochondria 3), encoding the ATP-binding cassette transporter of the mitochondria 3 (systematic name ABCB25), confirming the previously reported role of ATM3 in both FeS cluster and Moco biosynthesis. We also identified a mutant allele in CNX2, cofactor of nitrate reductase and xanthine dehydrogenase 2, encoding GTP 3′,8-cyclase, the first step in Moco biosynthesis which is localized in the mitochondria. A single-nucleotide polymorphism in cnx2-2 leads to substitution of Arg88 with Gln in the N-terminal FeS cluster-binding motif. cnx2-2 plants are small and chlorotic, with severely decreased Moco enzyme activities, but they performed better than a cnx2-1 knockout mutant, which could only survive with ammonia as a nitrogen source. Measurement of cyclic pyranopterin monophosphate (cPMP) levels by LC–MS/MS showed that this Moco intermediate was below the limit of detection in both cnx2-1 and cnx2-2, and accumulated more than 10-fold in seedlings mutated in the downstream gene CNX5. Interestingly, atm3-1 mutants had less cPMP than wild type, correlating with previous reports of a similar decrease in nitrate reductase activity. Taken together, our data functionally characterize CNX2 and suggest that ATM3 is indirectly required for cPMP synthesis. Portland Press Ltd. 2018-01-31 2018-01-31 /pmc/articles/PMC5791162/ /pubmed/29247140 http://dx.doi.org/10.1042/BCJ20170559 Text en © 2018 The Author(s) https://creativecommons.org/licenses/by/4.0/This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY) (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Research Articles
Kruse, Inga
Maclean, Andrew E.
Hill, Lionel
Balk, Janneke
Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria
title Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria
title_full Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria
title_fullStr Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria
title_full_unstemmed Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria
title_short Genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria
title_sort genetic dissection of cyclic pyranopterin monophosphate biosynthesis in plant mitochondria
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5791162/
https://www.ncbi.nlm.nih.gov/pubmed/29247140
http://dx.doi.org/10.1042/BCJ20170559
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