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The structure of Medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants

The two pathways for proline biosynthesis in higher plants share the last step, the conversion of δ(1)-pyrroline-5-carboxylate (P5C) to L-proline, which is catalyzed by P5C reductase (P5CR, EC 1.5.1.2) with the use of NAD(P)H as a coenzyme. There is increasing amount of evidence to suggest a complex...

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Autores principales: Ruszkowski, Milosz, Nocek, Boguslaw, Forlani, Giuseppe, Dauter, Zbigniew
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4626632/
https://www.ncbi.nlm.nih.gov/pubmed/26579138
http://dx.doi.org/10.3389/fpls.2015.00869
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author Ruszkowski, Milosz
Nocek, Boguslaw
Forlani, Giuseppe
Dauter, Zbigniew
author_facet Ruszkowski, Milosz
Nocek, Boguslaw
Forlani, Giuseppe
Dauter, Zbigniew
author_sort Ruszkowski, Milosz
collection PubMed
description The two pathways for proline biosynthesis in higher plants share the last step, the conversion of δ(1)-pyrroline-5-carboxylate (P5C) to L-proline, which is catalyzed by P5C reductase (P5CR, EC 1.5.1.2) with the use of NAD(P)H as a coenzyme. There is increasing amount of evidence to suggest a complex regulation of P5CR activity at the post-translational level, yet the molecular basis of these mechanisms is unknown. Here we report the three-dimensional structure of the P5CR enzyme from the model legume Medicago truncatula (Mt). The crystal structures of unliganded MtP5CR decamer, and its complexes with the products NAD(+), NADP(+), and L-proline were refined using x-ray diffraction data (at 1.7, 1.85, 1.95, and 2.1 Å resolution, respectively). Based on the presented structural data, the coenzyme preference for NADPH over NADH was explained, and NADPH is suggested to be the only coenzyme used by MtP5CR in vivo. Furthermore, the insensitivity of MtP5CR to feed-back inhibition by proline, revealed by enzymatic analysis, was correlated with structural features. Additionally, a mechanism for the modulation of enzyme activity by chloride anions is discussed, as well as the rationale for the possible development of effective enzyme inhibitors.
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spelling pubmed-46266322015-11-17 The structure of Medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants Ruszkowski, Milosz Nocek, Boguslaw Forlani, Giuseppe Dauter, Zbigniew Front Plant Sci Plant Science The two pathways for proline biosynthesis in higher plants share the last step, the conversion of δ(1)-pyrroline-5-carboxylate (P5C) to L-proline, which is catalyzed by P5C reductase (P5CR, EC 1.5.1.2) with the use of NAD(P)H as a coenzyme. There is increasing amount of evidence to suggest a complex regulation of P5CR activity at the post-translational level, yet the molecular basis of these mechanisms is unknown. Here we report the three-dimensional structure of the P5CR enzyme from the model legume Medicago truncatula (Mt). The crystal structures of unliganded MtP5CR decamer, and its complexes with the products NAD(+), NADP(+), and L-proline were refined using x-ray diffraction data (at 1.7, 1.85, 1.95, and 2.1 Å resolution, respectively). Based on the presented structural data, the coenzyme preference for NADPH over NADH was explained, and NADPH is suggested to be the only coenzyme used by MtP5CR in vivo. Furthermore, the insensitivity of MtP5CR to feed-back inhibition by proline, revealed by enzymatic analysis, was correlated with structural features. Additionally, a mechanism for the modulation of enzyme activity by chloride anions is discussed, as well as the rationale for the possible development of effective enzyme inhibitors. Frontiers Media S.A. 2015-10-30 /pmc/articles/PMC4626632/ /pubmed/26579138 http://dx.doi.org/10.3389/fpls.2015.00869 Text en Copyright © 2015 Ruszkowski, Nocek, Forlani and Dauter. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Plant Science
Ruszkowski, Milosz
Nocek, Boguslaw
Forlani, Giuseppe
Dauter, Zbigniew
The structure of Medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants
title The structure of Medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants
title_full The structure of Medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants
title_fullStr The structure of Medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants
title_full_unstemmed The structure of Medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants
title_short The structure of Medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants
title_sort structure of medicago truncatula δ(1)-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants
topic Plant Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4626632/
https://www.ncbi.nlm.nih.gov/pubmed/26579138
http://dx.doi.org/10.3389/fpls.2015.00869
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