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Pesara P, Szafran K, Nguyen HC, Sirohiwal A, Pantazis DA, Gabruk M. Elucidating substrate binding in the light-dependent protochlorophyllide oxidoreductase. Chem Sci 2024; 15:7767-7780. [PMID: 38784751 PMCID: PMC11110527 DOI: 10.1039/d4sc00923a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
The Light-Dependent Protochlorophyllide Oxidoreductase (LPOR) catalyzes a crucial step in chlorophyll biosynthesis: the rare biological photocatalytic reduction of the double C[double bond, length as m-dash]C bond in the precursor, protochlorophyllide (Pchlide). Despite its fundamental significance, limited structural insights into the active complex have hindered understanding of its reaction mechanism. Recently, a high-resolution cryo-EM structure of LPOR in its active conformation challenged our view of pigment binding, residue interactions, and the catalytic process. Surprisingly, this structure contrasts markedly with previous assumptions, particularly regarding the orientation of the bound Pchlide. To gain insights into the substrate binding puzzle, we conducted molecular dynamics simulations, quantum-mechanics/molecular-mechanics (QM/MM) calculations, and site-directed mutagenesis. Two Pchlide binding modes were considered, one aligning with historical proposals (mode A) and another consistent with the recent experimental data (mode B). Binding energy calculations revealed that in contrast to the non-specific interactions found for mode A, mode B exhibits distinct stabilizing interactions that support more thermodynamically favorable binding. A comprehensive analysis incorporating QM/MM-based local energy decomposition unraveled a complex interaction network involving Y177, H319, and the C131 carboxy group, influencing the pigment's excited state energy and potentially contributing to substrate specificity. Importantly, our results uniformly favor mode B, challenging established interpretations and emphasizing the need for a comprehensive re-evaluation of the LPOR reaction mechanism in a way that incorporates accurate structural information on pigment interactions and substrate-cofactor positioning in the binding pocket. The results shed light on the intricacies of LPOR's catalytic mechanism and provide a solid foundation for further elucidating the secrets of chlorophyll biosynthesis.
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Affiliation(s)
- Penelope Pesara
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Katarzyna Szafran
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Gronostajowa 7 30-387 Cracow Poland
| | - Henry C Nguyen
- Department of Biochemistry & Biophysics, Quantitative Biosciences Institute, University of California San Francisco CA USA
| | - Abhishek Sirohiwal
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University 10691 Stockholm Sweden
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Michal Gabruk
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University Gronostajowa 7 30-387 Cracow Poland
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Solymosi K, Mysliwa-Kurdziel B. The Role of Membranes and Lipid-Protein Interactions in the Mg-Branch of Tetrapyrrole Biosynthesis. FRONTIERS IN PLANT SCIENCE 2021; 12:663309. [PMID: 33995458 PMCID: PMC8113382 DOI: 10.3389/fpls.2021.663309] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/22/2021] [Indexed: 05/31/2023]
Abstract
Chlorophyll (Chl) is essential for photosynthesis and needs to be produced throughout the whole plant life, especially under changing light intensity and stress conditions which may result in the destruction and elimination of these pigments. All steps of the Mg-branch of tetrapyrrole biosynthesis leading to Chl formation are carried out by enzymes associated with plastid membranes. Still the significance of these protein-membrane and protein-lipid interactions in Chl synthesis and chloroplast differentiation are not very well-understood. In this review, we provide an overview on Chl biosynthesis in angiosperms with emphasis on its association with membranes and lipids. Moreover, the last steps of the pathway including the reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide), the biosynthesis of the isoprenoid phytyl moiety and the esterification of Chlide are also summarized. The unique biochemical and photophysical properties of the light-dependent NADPH:protochlorophyllide oxidoreductase (LPOR) enzyme catalyzing Pchlide photoreduction and located to peculiar tubuloreticular prolamellar body (PLB) membranes of light-deprived tissues of angiosperms and to envelope membranes, as well as to thylakoids (especially grana margins) are also reviewed. Data about the factors influencing tubuloreticular membrane formation within cells, the spectroscopic properties and the in vitro reconstitution of the native LPOR enzyme complexes are also critically discussed.
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Affiliation(s)
- Katalin Solymosi
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Beata Mysliwa-Kurdziel
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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Nguyen HC, Melo AA, Kruk J, Frost A, Gabruk M. Photocatalytic LPOR forms helical lattices that shape membranes for chlorophyll synthesis. NATURE PLANTS 2021; 7:437-444. [PMID: 33875834 DOI: 10.1038/s41477-021-00885-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 02/19/2021] [Indexed: 05/21/2023]
Abstract
Chlorophyll biosynthesis, crucial to life on Earth, is tightly regulated because its precursors are phototoxic1. In flowering plants, the enzyme light-dependent protochlorophyllide oxidoreductase (LPOR) captures photons to catalyse the penultimate reaction: the reduction of a double bond within protochlorophyllide (Pchlide) to generate chlorophyllide (Chlide)2,3. In darkness, LPOR oligomerizes to facilitate photon energy transfer and catalysis4,5. However, the complete three-dimensional structure of LPOR, the higher-order architecture of LPOR oligomers and the implications of these self-assembled states for catalysis, including how LPOR positions Pchlide and the co-factor NADPH, remain unknown. Here, we report the atomic structure of LPOR assemblies by electron cryo-microscopy. LPOR polymerizes with its substrates into helical filaments around constricted lipid bilayer tubes. Portions of LPOR and Pchlide insert into the outer membrane leaflet, targeting the product, Chlide, to the membrane for the final reaction site of chlorophyll biosynthesis. In addition to its crucial photocatalytic role, we show that in darkness LPOR filaments directly shape membranes into high-curvature tubules with the spectral properties of the prolamellar body, whose light-triggered disassembly provides lipids for thylakoid assembly. Moreover, our structure of the catalytic site challenges previously proposed reaction mechanisms6. Together, our results reveal a new and unexpected synergy between photosynthetic membrane biogenesis and chlorophyll synthesis in plants, orchestrated by LPOR.
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Affiliation(s)
- Henry C Nguyen
- Department of Biochemistry & Biophysics, Quantitative Biosciences Institute, University of California, San Francisco, CA, USA.
- Asher Biotherapeutics, South San Francisco, CA, USA.
| | - Arthur A Melo
- Department of Biochemistry & Biophysics, Quantitative Biosciences Institute, University of California, San Francisco, CA, USA
| | - Jerzy Kruk
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Adam Frost
- Department of Biochemistry & Biophysics, Quantitative Biosciences Institute, University of California, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
| | - Michal Gabruk
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
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Heyes DJ, Zhang S, Taylor A, Johannissen LO, Hardman SJO, Hay S, Scrutton NS. Photocatalysis as the 'master switch' of photomorphogenesis in early plant development. NATURE PLANTS 2021; 7:268-276. [PMID: 33686224 DOI: 10.1038/s41477-021-00866-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Enzymatic photocatalysis is seldom used in biology. Photocatalysis by light-dependent protochlorophyllide oxidoreductase (LPOR)-one of only a few natural light-dependent enzymes-is an exception, and is responsible for the conversion of protochlorophyllide to chlorophyllide in chlorophyll biosynthesis. Photocatalysis by LPOR not only regulates the biosynthesis of the most abundant pigment on Earth but it is also a 'master switch' in photomorphogenesis in early plant development. Following illumination, LPOR promotes chlorophyll production, plastid membranes are transformed and the photosynthetic apparatus is established. Given these remarkable, light-induced pigment and morphological changes, the LPOR-catalysed reaction has been extensively studied from catalytic, physiological and plant development perspectives, highlighting vital, and multiple, cellular roles of this intriguing enzyme. Here, we offer a perspective in which the link between LPOR photocatalysis and plant photomorphogenesis is explored. Notable breakthroughs in LPOR structural biology have uncovered the structural-mechanistic basis of photocatalysis. These studies have clarified how photon absorption by the pigment protochlorophyllide-bound in a ternary LPOR-protochlorophyllide-NADPH complex-triggers photocatalysis and a cascade of complex molecular and cellular events that lead to plant morphological changes. Photocatalysis is therefore the master switch responsible for early-stage plant development and ultimately life on Earth.
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Affiliation(s)
- Derren J Heyes
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK.
| | - Shaowei Zhang
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Aoife Taylor
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Linus O Johannissen
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Samantha J O Hardman
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Sam Hay
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK.
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5
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Crystal structures of cyanobacterial light-dependent protochlorophyllide oxidoreductase. Proc Natl Acad Sci U S A 2020; 117:8455-8461. [PMID: 32234783 DOI: 10.1073/pnas.1920244117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide) is the penultimate step of chlorophyll biosynthesis. In oxygenic photosynthetic bacteria, algae, and plants, this reaction can be catalyzed by the light-dependent Pchlide oxidoreductase (LPOR), a member of the short-chain dehydrogenase superfamily sharing a conserved Rossmann fold for NAD(P)H binding and the catalytic activity. Whereas modeling and simulation approaches have been used to study the catalytic mechanism of this light-driven reaction, key details of the LPOR structure remain unclear. We determined the crystal structures of LPOR from two cyanobacteria, Synechocystis sp. PCC 6803 and Thermosynechococcus elongatus Structural analysis defines the LPOR core fold, outlines the LPOR-NADPH interaction network, identifies the residues forming the substrate cavity and the proton-relay path, and reveals the role of the LPOR-specific loop. These findings provide a basis for understanding the structure-function relationships of the light-driven Pchlide reduction.
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Schneidewind J, Krause F, Bocola M, Stadler AM, Davari MD, Schwaneberg U, Jaeger KE, Krauss U. Consensus model of a cyanobacterial light-dependent protochlorophyllide oxidoreductase in its pigment-free apo-form and photoactive ternary complex. Commun Biol 2019; 2:351. [PMID: 31583285 PMCID: PMC6761149 DOI: 10.1038/s42003-019-0590-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 08/29/2019] [Indexed: 12/02/2022] Open
Abstract
Photosynthetic organisms employ two different enzymes for the reduction of the C17 = C18 double bond of protochlorophyllide (Pchlide), yielding the chlorophyll precursor chlorophyllide. First, a nitrogenase-like, light-independent (dark-operative) Pchlide oxidoreductase and secondly, a light-dependent Pchlide oxidoreductase (LPOR). For the latter enzyme, despite decades of research, no structural information is available. Here, we use protein structure modelling, molecular dynamics (MD) simulations combined with multi-wavelength analytical ultracentrifugation (MWA-AUC) and small angle X-ray scattering (SAXS) experiments to derive a consensus model of the LPOR apoprotein and the substrate/cofactor/LPOR ternary complex. MWA-AUC and SAXS experiments independently demonstrate that the apoprotein is monomeric, while ternary complex formation induces dimerization. SAXS-guided modelling studies provide a full-length model of the apoprotein and suggest a tentative mode of dimerization for the LPOR ternary complex, supported by published cross-link constraints. Our study provides a first impression of the LPOR structural organization.
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Affiliation(s)
- Judith Schneidewind
- Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Frank Krause
- Nanolytics, Gesellschaft für Kolloidanalytik GmbH, Am Mühlenberg 11, 14476 Potsdam, Germany
| | - Marco Bocola
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Andreas Maximilian Stadler
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Mehdi D. Davari
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Ulrich Schwaneberg
- Lehrstuhl für Biotechnologie, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
- DWI-Leibniz Institut für Interaktive Materialien, Forckenbeckstraße 50, 52056 Aachen, Germany
| | - Karl-Erich Jaeger
- Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
- IBG-1: Biotechnologie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Ulrich Krauss
- Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
- IBG-1: Biotechnologie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
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Stadler AM, Schneidewind J, Zamponi M, Knieps-Grünhagen E, Gholami S, Schwaneberg U, Rivalta I, Garavelli M, Davari MD, Jaeger KE, Krauss U. Ternary Complex Formation and Photoactivation of a Photoenzyme Results in Altered Protein Dynamics. J Phys Chem B 2019; 123:7372-7384. [PMID: 31380636 DOI: 10.1021/acs.jpcb.9b06608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interplay between protein dynamics and catalysis remains a fundamental question in enzymology. We here investigate the ns-timescale dynamics of a light-dependent NADPH:protochlorophyllide oxidoreductase (LPOR), a photoenzyme crucial for chlorophyll synthesis. LPORs catalyze the light-triggered trans addition of a hydride and a proton across the C17═C18 double bond of the chlorophyll precursor protochlorophyllide (Pchlide). Because of the lack of an LPOR structure, the global structural and dynamic consequences of LPOR/Pchlide/NADPH ternary complex formation remain elusive. Moreover, photoactivation of LPORs by low-light preillumination is controversially discussed as unequivocal proof for this phenomenon is lacking. By employing quasielastic neutron spectroscopy (QENS), we show that the formation of the ternary holoprotein complex as well as photoactivation lead to progressive rigidification of the protein. These findings are supported by thermostability measurements, which reveal different melting behavior and thermostabilities for the apo- and holoprotein ternary complexes. Molecular dynamics simulations in good agreement with the experimental QENS results suggest that the increased flexibility observed for the apoprotein stems from structural fluctuations of the NADPH and Pchlide substrate binding sites of the enzyme. On the basis of our results, in conjunction with activity and stability measurements, we provide independent proof for LPOR photoactivation, defined as a process that modifies the protein structure and dynamics, resulting in an increased substrate turnover. Our findings advance the structural and dynamic understanding of LPORs and provide a first link between protein dynamics and catalysis for this enzyme class.
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Affiliation(s)
| | | | - Michaela Zamponi
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) , Forschungszentrum Jülich GmbH , Lichtenbergstr. 1 , 85748 Garching , Germany
| | | | - Samira Gholami
- Dipartimento di Chimica Industriale , Università degli Studi di Bologna , Viale del Risorgimento 4 , I-40136 Bologna , Italy
| | - Ulrich Schwaneberg
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany.,DWI-Leibniz Institute for Interactive Materials , Forckenbeckstraße 50 , 52056 Aachen , Germany
| | - Ivan Rivalta
- Université de Lyon, École Normale Supérieure de Lyon, CNRS, Université Claude Bernard Lyon 1, Laboratoire de Chimie UMR 5182 , F-69342 Lyon , France
| | - Marco Garavelli
- Dipartimento di Chimica Industriale , Università degli Studi di Bologna , Viale del Risorgimento 4 , I-40136 Bologna , Italy.,École Normale Supérieure de Lyon, CNRS, Laboratoire de Chimie UMR 5182, Université de Lyon , 46 Allée d'Italie , F-69364 Lyon Cedex 07 , France
| | - Mehdi D Davari
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Karl-Erich Jaeger
- IBG-1: Biotechnologie , Forschungszentrum Jülich GmbH , D-52425 Jülich , Germany
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