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Siritanaratkul B, Megarity CF, Herold RA, Armstrong FA. Interactive biocatalysis achieved by driving enzyme cascades inside a porous conducting material. Commun Chem 2024; 7:132. [PMID: 38858478 DOI: 10.1038/s42004-024-01211-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 05/28/2024] [Indexed: 06/12/2024] Open
Abstract
An emerging concept and platform, the electrochemical Leaf (e-Leaf), offers a radical change in the way tandem (multi-step) catalysis by enzyme cascades is studied and exploited. The various enzymes are loaded into an electronically conducting porous material composed of metallic oxide nanoparticles, where they achieve high concentration and crowding - in the latter respect the environment resembles that found in living cells. By exploiting efficient electron tunneling between the nanoparticles and one of the enzymes, the e-Leaf enables the user to interact directly with complex networks, rendering simultaneous the abilities to energise, control and observe catalysis. Because dispersion of intermediates is physically suppressed, the output of the cascade - the rate of flow of chemical steps and information - is delivered in real time as electrical current. Myriad enzymes of all major classes now become effectively electroactive in a technology that offers scalability between micro-(analytical, multiplex) and macro-(synthesis) levels. This Perspective describes how the e-Leaf was discovered, the steps in its development so far, and the outlook for future research and applications.
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Affiliation(s)
| | - Clare F Megarity
- Department of Chemistry, Manchester Institute of Biotechnology, University of Manchester, Manchester, M1 7DN, UK
| | - Ryan A Herold
- Department of Chemistry, University of Oxford, Oxford, OX1 3QR, UK
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, 92093, USA
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2
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Dolińska MM, Kirwan AJ, Megarity CF. Retuning the potential of the electrochemical leaf. Faraday Discuss 2024. [PMID: 38848142 DOI: 10.1039/d4fd00020j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2024]
Abstract
The electrochemical leaf enables the electrification and control of multi-enzyme cascades by exploiting two discoveries: (i) the ability to electrify the photosynthetic enzyme ferredoxin NADP+ reductase (FNR), driving it to catalyse the interconversion of NADP+/NADPH whilst it is entrapped in a highly porous, metal oxide electrode, and (ii) the evidence that additional enzymes can be co-entrapped in the electrode pores where, through one NADP(H)-dependent enzyme, extended cascades can be driven by electrical connection to FNR, via NADP(H) recycling. By changing a critical active-site tyrosine to serine, FNR's exclusivity for NADP(H) is swapped for unphosphorylated NAD(H). Here we present an electrochemical study of this variant FNR, and show that in addition to the intended inversion of cofactor preference, this change to the active site has altered FNR's tuning of the flavin reduction potential, making it less reductive. Exploiting the ability to monitor the variant's activity with NADP(H) as a function of potential has revealed a trapped intermediate state, relieved only by applying a negative overpotential, which allows catalysis to proceed. Inhibition by NADP+ (very tightly bound) with respect to NAD(H) turnover was also revealed and interestingly, this inhibition changes depending on the applied potential. These findings are of critical importance for future exploitation of the electrochemical leaf.
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Affiliation(s)
- Marta M Dolińska
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
| | - Adam J Kirwan
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
| | - Clare F Megarity
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
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3
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Smith CO, Moran GR. Elucidation of the Catalytic Sequence of Dihydroorotate Dehydrogenase B from Lactoccocus lactis: Evidence for Accumulation of a Flavin Bisemiquinone State in Catalysis. Biochemistry 2024; 63:1347-1358. [PMID: 38691339 DOI: 10.1021/acs.biochem.4c00025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
The physiological role of dihydroorotate dehydrogenase (DHOD) enzymes is to catalyze the oxidation of dihydroorotate to orotate in pyrimidine biosynthesis. DHOD enzymes are structurally diverse existing as both soluble and membrane-associated forms. The Family 1 enzymes are soluble and act either as conventional single subunit flavin-dependent dehydrogenases known as Class 1A (DHODA) or as unusual heterodimeric enzymes known as Class 1B (DHODB). DHODBs possess two active sites separated by ∼20 Å, each with a noncovalently bound flavin cofactor. NAD is thought to interact at the FAD containing site, and the pyrimidine substrate is known to bind at the FMN containing site. At the approximate center of the protein is a single Fe2S2 center that is assumed to act as a conduit, facilitating one-electron transfers between the flavins. We present anaerobic transient state analysis of a DHODB enzyme from Lactoccocus lactis. The data presented primarily report the exothermic reaction that reduces orotate to dihydroorotate. The reductive half reaction reveals rapid two-electron reduction that is followed by the accumulation of a four-electron reduced state when NADH is added in excess, suggesting that the initial two electrons acquired reside on the FMN cofactor. Concomitant with the first reduction is the accumulation of a long-wavelength absorption feature consistent with the blue form of a flavin semiquinone. Spectral deconvolution and fitting to a model that includes reversibility for the second electron transfer reveals equilibrium accumulation of a flavin bisemiquinone state that has features of both red and blue semiquinones. Single turnover reactions with limiting NADH and excess orotate reveal that the flavin bisemiquinone accumulates with reduction of the enzyme by NADH and decays with reduction of the pyrimidine substrate, establishing the bisemiquinone as a fractional state of the two-electron reduced intermediate observed.
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Affiliation(s)
- Corine O Smith
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan Rd Chicago Illinois 60660, United States
| | - Graham R Moran
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan Rd Chicago Illinois 60660, United States
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4
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Fagnani E, Cocomazzi P, Pellegrino S, Tedeschi G, Scalvini FG, Cossu F, Da Vela S, Aliverti A, Mastrangelo E, Milani M. CHCHD4 binding affects the active site of apoptosis inducing factor (AIF): Structural determinants for allosteric regulation. Structure 2024; 32:594-602.e4. [PMID: 38460521 DOI: 10.1016/j.str.2024.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 01/08/2024] [Accepted: 02/13/2024] [Indexed: 03/11/2024]
Abstract
Apoptosis-inducing factor (AIF), which is confined to mitochondria of normal healthy cells, is the first identified caspase-independent cell death effector. Moreover, AIF is required for the optimal functioning of the respiratory chain machinery. Recent findings have revealed that AIF fulfills its pro-survival function by interacting with CHCHD4, a soluble mitochondrial protein which promotes the entrance and the oxidative folding of different proteins in the inner membrane space. Here, we report the crystal structure of the ternary complex involving the N-terminal 27-mer peptide of CHCHD4, NAD+, and AIF harboring its FAD (flavin adenine dinucleotide) prosthetic group in oxidized form. Combining this information with biophysical and biochemical data on the CHCHD4/AIF complex, we provide a detailed structural description of the interaction between the two proteins, validated by both chemical cross-linking mass spectrometry analysis and site-directed mutagenesis.
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Affiliation(s)
- Elisa Fagnani
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Paolo Cocomazzi
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Sara Pellegrino
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Via Golgi 19, 20133 Milan, Italy
| | - Gabriella Tedeschi
- Department of Veterinary Medicine and Animal Science (DIVAS), Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy; Cimaina, Università degli Studi di Milano, Milan, Italy
| | - Francesca Grassi Scalvini
- Department of Veterinary Medicine and Animal Science (DIVAS), Università degli Studi di Milano, Via dell'Università 6, 26900 Lodi, Italy
| | - Federica Cossu
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Stefano Da Vela
- Hochschule Bremerhaven, Karlstadt 8, 27568 Bremerhaven, Germany
| | - Alessandro Aliverti
- Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
| | - Eloise Mastrangelo
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
| | - Mario Milani
- Biophysics Institute, CNR-IBF, Via Corti 12, 20133 Milan, Italy; Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
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5
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Petit-Hartlein I, Vermot A, Thepaut M, Humm AS, Dupeux F, Dupuy J, Chaptal V, Marquez JA, Smith SME, Fieschi F. X-ray structure and enzymatic study of a bacterial NADPH oxidase highlight the activation mechanism of eukaryotic NOX. eLife 2024; 13:RP93759. [PMID: 38640072 PMCID: PMC11031084 DOI: 10.7554/elife.93759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024] Open
Abstract
NADPH oxidases (NOX) are transmembrane proteins, widely spread in eukaryotes and prokaryotes, that produce reactive oxygen species (ROS). Eukaryotes use the ROS products for innate immune defense and signaling in critical (patho)physiological processes. Despite the recent structures of human NOX isoforms, the activation of electron transfer remains incompletely understood. SpNOX, a homolog from Streptococcus pneumoniae, can serves as a robust model for exploring electron transfers in the NOX family thanks to its constitutive activity. Crystal structures of SpNOX full-length and dehydrogenase (DH) domain constructs are revealed here. The isolated DH domain acts as a flavin reductase, and both constructs use either NADPH or NADH as substrate. Our findings suggest that hydride transfer from NAD(P)H to FAD is the rate-limiting step in electron transfer. We identify significance of F397 in nicotinamide access to flavin isoalloxazine and confirm flavin binding contributions from both DH and Transmembrane (TM) domains. Comparison with related enzymes suggests that distal access to heme may influence the final electron acceptor, while the relative position of DH and TM does not necessarily correlate with activity, contrary to previous suggestions. It rather suggests requirement of an internal rearrangement, within the DH domain, to switch from a resting to an active state. Thus, SpNOX appears to be a good model of active NOX2, which allows us to propose an explanation for NOX2's requirement for activation.
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Affiliation(s)
| | - Annelise Vermot
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie StructuraleGrenobleFrance
| | - Michel Thepaut
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie StructuraleGrenobleFrance
| | | | - Florine Dupeux
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie StructuraleGrenobleFrance
- European Molecular Biology LaboratoryGrenobleFrance
| | - Jerome Dupuy
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie StructuraleGrenobleFrance
| | | | | | - Susan ME Smith
- Department of Molecular and Cellular Biology, Kennesaw State UniversityKennesawUnited States
| | - Franck Fieschi
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie StructuraleGrenobleFrance
- Institut Universitaire de FranceParisFrance
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6
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Liu X, Shi Y, Liu R, Song K, Chen L. Structure of human phagocyte NADPH oxidase in the activated state. Nature 2024; 627:189-195. [PMID: 38355798 DOI: 10.1038/s41586-024-07056-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/10/2024] [Indexed: 02/16/2024]
Abstract
Phagocyte NADPH oxidase, a protein complex with a core made up of NOX2 and p22 subunits, is responsible for transferring electrons from intracellular NADPH to extracellular oxygen1. This process generates superoxide anions that are vital for killing pathogens1. The activation of phagocyte NADPH oxidase requires membrane translocation and the binding of several cytosolic factors2. However, the exact mechanism by which cytosolic factors bind to and activate NOX2 is not well understood. Here we present the structure of the human NOX2-p22 complex activated by fragments of three cytosolic factors: p47, p67 and Rac1. The structure reveals that the p67-Rac1 complex clamps onto the dehydrogenase domain of NOX2 and induces its contraction, which stabilizes the binding of NADPH and results in a reduction of the distance between the NADPH-binding domain and the flavin adenine dinucleotide (FAD)-binding domain. Furthermore, the dehydrogenase domain docks onto the bottom of the transmembrane domain of NOX2, which reduces the distance between FAD and the inner haem. These structural rearrangements might facilitate the efficient transfer of electrons between the redox centres in NOX2 and lead to the activation of phagocyte NADPH oxidase.
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Affiliation(s)
- Xiaoyu Liu
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yiting Shi
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Rui Liu
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Kangcheng Song
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China.
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.
- National Biomedical Imaging Center, Peking University, Beijing, China.
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7
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Kimata-Ariga Y, Shinkoda R, Abe R. Inter-domain interaction of ferredoxin-NADP+ reductase important for the negative cooperativity by ferredoxin and NADP(H). J Biochem 2023; 174:327-334. [PMID: 37311065 DOI: 10.1093/jb/mvad046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/26/2023] [Accepted: 06/09/2023] [Indexed: 06/15/2023] Open
Abstract
Ferredoxin-NADP+ reductase (FNR) in plants receives electrons from ferredoxin (Fd) and converts NADP+ to NADPH. The affinity between FNR and Fd is weakened by the allosteric binding of NADP(H) on FNR, which is considered as a part of negative cooperativity. We have been investigating the molecular mechanism of this phenomenon and proposed that the NADP(H)-binding signal is transferred to the Fd-binding region across the two domains of FNR, NADP(H)-binding domain and FAD-binding domain. In this study, we analyzed the effect of altering the inter-domain interaction of FNR on the negative cooperativity. Four site-directed FNR mutants at the inter-domain region were prepared, and their NADPH-dependent changes in the Km for Fd and physical binding ability to Fd were investigated. Two mutants, in which an inter-domain hydrogen bond was changed to a disulfide bond (FNR D52C/S208C) and an inter-domain salt bridge was lost (FNR D104N), were shown to suppress the negative cooperativity by using kinetic analysis and Fd-affinity chromatography. These results showed that the inter-domain interaction of FNR is important for the negative cooperativity, suggesting that the allosteric NADP(H)-binding signal is transferred to Fd-binging region by conformational changes involving inter-domain interactions of FNR.
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Affiliation(s)
- Yoko Kimata-Ariga
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan
| | - Rina Shinkoda
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan
| | - Ryuya Abe
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan
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Armstrong FA, Cheng B, Herold RA, Megarity CF, Siritanaratkul B. From Protein Film Electrochemistry to Nanoconfined Enzyme Cascades and the Electrochemical Leaf. Chem Rev 2022; 123:5421-5458. [PMID: 36573907 PMCID: PMC10176485 DOI: 10.1021/acs.chemrev.2c00397] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Protein film electrochemistry (PFE) has given unrivalled insight into the properties of redox proteins and many electron-transferring enzymes, allowing investigations of otherwise ill-defined or intractable topics such as unstable Fe-S centers and the catalytic bias of enzymes. Many enzymes have been established to be reversible electrocatalysts when attached to an electrode, and further investigations have revealed how unusual dependences of catalytic rates on electrode potential have stark similarities with electronics. A special case, the reversible electrochemistry of a photosynthetic enzyme, ferredoxin-NADP+ reductase (FNR), loaded at very high concentrations in the 3D nanopores of a conducting metal oxide layer, is leading to a new technology that brings PFE to myriad enzymes of other classes, the activities of which become controlled by the primary electron exchange. This extension is possible because FNR-based recycling of NADP(H) can be coupled to a dehydrogenase, and thence to other enzymes linked in tandem by the tight channelling of cofactors and intermediates within the nanopores of the material. The earlier interpretations of catalytic wave-shapes and various analogies with electronics are thus extended to initiate a field perhaps aptly named "cascade-tronics", in which the flow of reactions along an enzyme cascade is monitored and controlled through an electrochemical analyzer. Unlike in photosynthesis where FNR transduces electron transfer and hydride transfer through the unidirectional recycling of NADPH, the "electrochemical leaf" (e-Leaf) can be used to drive reactions in both oxidizing and reducing directions. The e-Leaf offers a natural way to study how enzymes are affected by nanoconfinement and crowding, mimicking the physical conditions under which enzyme cascades operate in living cells. The reactions of the trapped enzymes, often at very high local concentration, are thus studied electrochemically, exploiting the potential domain to control rates and direction and the current-rate analogy to derive kinetic data. Localized NADP(H) recycling is very efficient, resulting in very high cofactor turnover numbers and new opportunities for controlling and exploiting biocatalysis.
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Affiliation(s)
- Fraser A. Armstrong
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Beichen Cheng
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Ryan A. Herold
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Clare F. Megarity
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Bhavin Siritanaratkul
- Stephenson Institute for Renewable Energy and the Department of Chemistry, University of Liverpool, Liverpool L69 7ZF, United Kingdom
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9
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Kimata-Ariga Y, Fukuta K, Miyata M. Role of Histidine 78 of leaf ferredoxin in the interaction with ferredoxin-NADP+ reductase: regulation of pH dependency and negative cooperativity with NADP(H). Biosci Biotechnol Biochem 2022; 86:618-623. [PMID: 35136937 DOI: 10.1093/bbb/zbac022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/01/2022] [Indexed: 11/12/2022]
Abstract
In chloroplast stroma, dynamic pH change occurs in response to fluctuating light conditions. We investigated the pH-dependent electron transfer activity between ferredoxin-NADP+ reductase (FNR) and ferredoxin (Fd) isoproteins from maize leaves. By increasing pH (from 5.5 to 8.5), the electron transfer activity from FNR to photosynthetic-type Fd (Fd1) significantly increased while the activity to nonphotosynthetic type Fd (Fd3) decreased, which was mainly due to their differences in the pH dependency of Km for Fd. Mutation of His78 of Fd1 to Val, corresponding amino acid residue in Fd3, lost the pH dependency, indicating a regulatory role of the His78 in the interaction with FNR. We previously showed that the interaction between FNR and Fd was weakened by the allosteric binding of NADP(H) on FNR. His78Val Fd1 mutant largely suppressed this negative cooperativity. These results indicate the involvement of Fd1 His78 in pH dependency and negative cooperativity in the interaction with FNR.
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Affiliation(s)
- Yoko Kimata-Ariga
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi, Japan
| | - Karen Fukuta
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi, Japan
| | - Masayuki Miyata
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Yamaguchi, Japan
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Pérez-Domínguez S, Caballero-Mancebo S, Marcuello C, Martínez-Júlvez M, Medina M, Lostao A. Nanomechanical Study of Enzyme: Coenzyme Complexes: Bipartite Sites in Plastidic Ferredoxin-NADP+ Reductase for the Interaction with NADP+. Antioxidants (Basel) 2022; 11:antiox11030537. [PMID: 35326186 PMCID: PMC8944804 DOI: 10.3390/antiox11030537] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 12/04/2022] Open
Abstract
Plastidic ferredoxin-NADP+ reductase (FNR) transfers two electrons from two ferredoxin or flavodoxin molecules to NADP+, generating NADPH. The forces holding the Anabaena FNR:NADP+ complex were analyzed by dynamic force spectroscopy, using WT FNR and three C-terminal Y303 variants, Y303S, Y303F, and Y303W. FNR was covalently immobilized on mica and NADP+ attached to AFM tips. Force–distance curves were collected for different loading rates and specific unbinding forces were analyzed under the Bell–Evans model to obtain the mechanostability parameters associated with the dissociation processes. The WT FNR:NADP+ complex presented a higher mechanical stability than that reported for the complexes with protein partners, corroborating the stronger affinity of FNR for NADP+. The Y303 mutation induced changes in the FNR:NADP+ interaction mechanical stability. NADP+ dissociated from WT and Y303W in a single event related to the release of the adenine moiety of the coenzyme. However, two events described the Y303S:NADP+ dissociation that was also a more durable complex due to the strong binding of the nicotinamide moiety of NADP+ to the catalytic site. Finally, Y303F shows intermediate behavior. Therefore, Y303, reported as crucial for achieving catalytically competent active site geometry, also regulates the concerted dissociation of the bipartite nucleotide moieties of the coenzyme.
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Affiliation(s)
- Sandra Pérez-Domínguez
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain; (S.P.-D.); (S.C.-M.); (C.M.)
| | - Silvia Caballero-Mancebo
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain; (S.P.-D.); (S.C.-M.); (C.M.)
| | - Carlos Marcuello
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain; (S.P.-D.); (S.C.-M.); (C.M.)
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
| | - Marta Martínez-Júlvez
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (BIFI) (GBsC-CSIC Joint Unit), Universidad de Zaragoza, 50018 Zaragoza, Spain;
| | - Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (BIFI) (GBsC-CSIC Joint Unit), Universidad de Zaragoza, 50018 Zaragoza, Spain;
- Correspondence: (M.M.); (A.L.); Tel.: +34-976762476 (M.M.); +34-876555357 (A.L.)
| | - Anabel Lostao
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain; (S.P.-D.); (S.C.-M.); (C.M.)
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Fundación ARAID, 50018 Zaragoza, Spain
- Correspondence: (M.M.); (A.L.); Tel.: +34-976762476 (M.M.); +34-876555357 (A.L.)
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11
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Effect of Artemisinin on the Redox System of NADPH/FNR/Ferredoxin from Malaria Parasites. Antioxidants (Basel) 2022; 11:antiox11020273. [PMID: 35204156 PMCID: PMC8868210 DOI: 10.3390/antiox11020273] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 11/17/2022] Open
Abstract
FNR and ferredoxin constitute a redox cascade, which provides reducing power in the plastid of malaria parasites. Recently, mutation of ferredoxin (D97Y) was reported to be strongly related to the parasite’s resistance to the front-line antimalarial drug artemisinin. In order to gain insight into the mechanism for the resistance, we studied the effect of dihydroartemisinin (DHA), the active compound of artemisinin, on the redox cascade of NADPH/FNR/ferredoxin in in vitro reconstituted systems. DHA partially inhibited the diaphorase activity of FNR by decreasing the affinity of FNR for NADPH. The activity of the electron transfer from FNR to wild-type or D97Y mutant ferredoxin was not significantly affected by DHA. An in silico docking analysis indicated possible binding of DHA molecule in the binding cavity of 2′5′ADP, a competitive inhibitor for NADPH, on FNR. We previously showed that the D97Y mutant of ferredoxin binds to FNR more strongly than wild-type ferredoxin, and ferredoxin and FNR are generally known to be involved in the oxidative stress response. Thus, these results suggest that ferredoxin is not a direct target of artemisinin, but its mutation may be involved in the protective response against the oxidative stress caused by artemisinin.
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12
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Monchietti P, López Rivero AS, Ceccarelli EA, Catalano‐Dupuy DL. A new catalytic mechanism of bacterial ferredoxin-NADP + reductases due to a particular NADP + binding mode. Protein Sci 2021; 30:2106-2120. [PMID: 34382711 PMCID: PMC8442965 DOI: 10.1002/pro.4166] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/21/2021] [Accepted: 08/01/2021] [Indexed: 01/19/2023]
Abstract
Ferredoxin-NADP+ reductases (FNRs) are ubiquitous flavoenzymes involved in redox metabolisms. FNRs catalyze the reversible electron transfer between NADP(H) and ferredoxin or flavodoxin. They are classified as plant- and mitochondrial-type FNR. Plant-type FNRs are divided into plastidic and bacterial classes. The plastidic FNRs show turnover numbers between 20 and 100 times higher than bacterial enzymes and these differences have been related to their physiological functions. We demonstrated that purified Escherichia coli FPR (EcFPR) contains tightly bound NADP+ , which does not occur in plastidic type FNRs. The three-dimensional structure of EcFPR evidenced that NADP+ interacts with three arginines (R144, R174, and R184) which could generate a very high affinity and structured site. These arginines are conserved in other bacterial FNRs but not in the plastidic enzymes. We have cross-substituted EcFPR arginines with residues present in analogous positions in the Pisum sativum FNR (PsFNR) and replaced these amino acids by arginines in PsFNR. We analyzed all proteins by structural, kinetic, and stability studies. We found that EcFPR mutants do not contain bound NADP+ and showed increased Km for this nucleotide. The EcFPR activity was inhibited by NADP+ but this behavior disappeared as arginines were removed. A NADP+ analog of the nicotinamide portion produced an activating effect on EcFPR and promoted the NADP+ release. Our results give evidence for a new model of NADP+ binding and catalysis in bacterial FNRs.We propose that this tight NADP+ binding constitutes an essential catalytic and regulatory mechanism of bacterial FNRs involved in redox homeostasis.
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Affiliation(s)
- Paula Monchietti
- Instituto de Biología Molecular y Celular de Rosario (IBR)CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y EsmeraldaRosarioArgentina
| | - Arleth S. López Rivero
- Instituto de Biología Molecular y Celular de Rosario (IBR)CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y EsmeraldaRosarioArgentina
- Grupo de Investigaciones en Gestión Ecológica y Agroindustrial, Universidad Libre SecBarranquillaColombia
| | - Eduardo A. Ceccarelli
- Instituto de Biología Molecular y Celular de Rosario (IBR)CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y EsmeraldaRosarioArgentina
| | - Daniela L. Catalano‐Dupuy
- Instituto de Biología Molecular y Celular de Rosario (IBR)CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Ocampo y EsmeraldaRosarioArgentina
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13
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Armstrong FA. Some fundamental insights into biological redox catalysis from the electrochemical characteristics of enzymes attached directly to electrodes. Electrochim Acta 2021; 390:138836. [PMID: 34511630 PMCID: PMC8386245 DOI: 10.1016/j.electacta.2021.138836] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/21/2021] [Accepted: 06/21/2021] [Indexed: 01/03/2023]
Abstract
This article outlines examples of where electrochemical investigations of electrocatalysis by proteins immobilised on an electrode reveal fundamental information about electron-proton coupling in catalysis and provide a new way to energise, control and observe multi-enzyme cascades.
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14
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Chikuma Y, Miyata M, Lee YH, Hase T, Kimata-Ariga Y. Molecular mechanism of negative cooperativity of ferredoxin-NADP+ reductase by ferredoxin and NADP(H): involvement of a salt bridge between Asp60 of ferredoxin and Lys33 of FNR. Biosci Biotechnol Biochem 2021; 85:860-865. [PMID: 33693505 DOI: 10.1093/bbb/zbaa102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/03/2020] [Indexed: 11/13/2022]
Abstract
Ferredoxin-NADP+ reductase (FNR) in plants receives electrons from ferredoxin (Fd) and converts NADP+ to NADPH at the end of the photosynthetic electron transfer chain. We previously showed that the interaction between FNR and Fd was weakened by the allosteric binding of NADP(H) on FNR, which was considered as a part of negative cooperativity. In this study, we investigated the molecular mechanism of this phenomenon using maize FNR and Fd, as the three-dimensional structure of this Fd:FNR complex is available. NMR chemical shift perturbation analysis identified a site (Asp60) on Fd molecule which was selectively affected by NADP(H) binding on FNR. Asp60 of Fd forms a salt bridge with Lys33 of FNR in the complex. Site-specific mutants of FdD60 and FNRK33 suppressed the negative cooperativity (downregulation of the interaction between FNR and Fd by NADPH), indicating that a salt bridge between FdD60 and FNRK33 is involved in this negative cooperativity.
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Affiliation(s)
- Yutaro Chikuma
- Division of Protein chemistry, Institute for Protein Research, Osaka University, Suita, Japan
| | - Masayuki Miyata
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Japan
| | - Young-Ho Lee
- Division of Protein chemistry, Institute for Protein Research, Osaka University, Suita, Japan
| | - Toshiharu Hase
- Division of Protein chemistry, Institute for Protein Research, Osaka University, Suita, Japan
| | - Yoko Kimata-Ariga
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Japan
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15
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Megarity CF, Siritanaratkul B, Herold RA, Morello G, Armstrong FA. Electron flow between the worlds of Marcus and Warburg. J Chem Phys 2021; 153:225101. [PMID: 33317312 DOI: 10.1063/5.0024701] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Living organisms are characterized by the ability to process energy (all release heat). Redox reactions play a central role in biology, from energy transduction (photosynthesis, respiratory chains) to highly selective catalyzed transformations of complex molecules. Distance and scale are important: electrons transfer on a 1 nm scale, hydrogen nuclei transfer between molecules on a 0.1 nm scale, and extended catalytic processes (cascades) operate most efficiently when the different enzymes are under nanoconfinement (10 nm-100 nm scale). Dynamic electrochemistry experiments (defined broadly within the term "protein film electrochemistry," PFE) reveal details that are usually hidden in conventional kinetic experiments. In PFE, the enzyme is attached to an electrode, often in an innovative way, and electron-transfer reactions, individual or within steady-state catalytic flow, can be analyzed in terms of precise potentials, proton coupling, cooperativity, driving-force dependence of rates, and reversibility (a mark of efficiency). The electrochemical experiments reveal subtle factors that would have played an essential role in molecular evolution. This article describes how PFE is used to visualize and analyze different aspects of biological redox chemistry, from long-range directional electron transfer to electron/hydride (NADPH) interconversion by a flavoenzyme and finally to NADPH recycling in a nanoconfined enzyme cascade.
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Affiliation(s)
- Clare F Megarity
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
| | | | - Ryan A Herold
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
| | - Giorgio Morello
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
| | - Fraser A Armstrong
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
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16
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Reis RAG, Li H, Johnson M, Sobrado P. New frontiers in flavin-dependent monooxygenases. Arch Biochem Biophys 2021; 699:108765. [PMID: 33460580 DOI: 10.1016/j.abb.2021.108765] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 12/15/2022]
Abstract
Flavin-dependent monooxygenases catalyze a wide variety of redox reactions in important biological processes and are responsible for the synthesis of highly complex natural products. Although much has been learned about FMO chemistry in the last ~80 years of research, several aspects of the reactions catalyzed by these enzymes remain unknown. In this review, we summarize recent advancements in the flavin-dependent monooxygenase field including aspects of flavin dynamics, formation and stabilization of reactive species, and the hydroxylation mechanism. Novel catalysis of flavin-dependent N-oxidases involving consecutive oxidations of amines to generate oximes or nitrones is presented and the biological relevance of the products is discussed. In addition, the activity of some FMOs have been shown to be essential for the virulence of several human pathogens. We also discuss the biomedical relevance of FMOs in antibiotic resistance and the efforts to identify inhibitors against some members of this important and growing family enzymes.
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Affiliation(s)
| | - Hao Li
- Department of Biochemistry, Blacksburg, VA, 24061, USA
| | - Maxim Johnson
- Department of Biochemistry, Blacksburg, VA, 24061, USA
| | - Pablo Sobrado
- Department of Biochemistry, Blacksburg, VA, 24061, USA; Center for Drug Discovery, Virginia Tech, Blacksburg, VA, 24061, USA.
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17
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Structures of human dual oxidase 1 complex in low-calcium and high-calcium states. Nat Commun 2021; 12:155. [PMID: 33420071 PMCID: PMC7794343 DOI: 10.1038/s41467-020-20466-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/02/2020] [Indexed: 01/29/2023] Open
Abstract
Dual oxidases (DUOXs) produce hydrogen peroxide by transferring electrons from intracellular NADPH to extracellular oxygen. They are involved in many crucial biological processes and human diseases, especially in thyroid diseases. DUOXs are protein complexes co-assembled from the catalytic DUOX subunits and the auxiliary DUOXA subunits and their activities are regulated by intracellular calcium concentrations. Here, we report the cryo-EM structures of human DUOX1-DUOXA1 complex in both high-calcium and low-calcium states. These structures reveal the DUOX1 complex is a symmetric 2:2 hetero-tetramer stabilized by extensive inter-subunit interactions. Substrate NADPH and cofactor FAD are sandwiched between transmembrane domain and the cytosolic dehydrogenase domain of DUOX. In the presence of calcium ions, intracellular EF-hand modules might enhance the catalytic activity of DUOX by stabilizing the dehydrogenase domain in a conformation that allows electron transfer.
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18
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Rodriguez Buitrago JA, Klünemann T, Blankenfeldt W, Schallmey A. Expression, purification and crystal structure determination of a ferredoxin reductase from the actinobacterium Thermobifida fusca. Acta Crystallogr F Struct Biol Commun 2020; 76:334-340. [PMID: 32744244 PMCID: PMC7397466 DOI: 10.1107/s2053230x2000922x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/06/2020] [Indexed: 11/10/2022] Open
Abstract
The ferredoxin reductase FdR9 from Thermobifida fusca, a member of the oxygenase-coupled NADH-dependent ferredoxin reductase (FNR) family, catalyses electron transfer from NADH to its physiological electron acceptor ferredoxin. It forms part of a putative three-component cytochrome P450 monooxygenase system in T. fusca comprising CYP222A1 and the [3Fe-4S]-cluster ferredoxin Fdx8 as well as FdR9. Here, FdR9 was overexpressed and purified and its crystal structure was determined at 1.9 Å resolution. The overall structure of FdR9 is similar to those of other members of the FNR family and is composed of an FAD-binding domain, an NAD-binding domain and a C-terminal domain. Activity measurements with FdR9 confirmed a strong preference for NADH as the cofactor. Comparison of the FAD- and NAD-binding domains of FdR9 with those of other ferredoxin reductases revealed the presence of conserved sequence motifs in the FAD-binding domain as well as several highly conserved residues involved in FAD and NAD cofactor binding. Moreover, the NAD-binding site of FdR9 contains a modified Rossmann-fold motif, GxSxxS, instead of the classical GxGxxG motif.
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Affiliation(s)
- Jhon Alexander Rodriguez Buitrago
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technical University Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Thomas Klünemann
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Wulf Blankenfeldt
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technical University Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Anett Schallmey
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technical University Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
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19
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The Hydride Transfer Process in NADP-dependent Methylene-tetrahydromethanopterin Dehydrogenase. J Mol Biol 2020; 432:2042-2054. [PMID: 32061937 DOI: 10.1016/j.jmb.2020.01.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/24/2020] [Accepted: 01/28/2020] [Indexed: 11/22/2022]
Abstract
NADP-dependent methylene-tetrahydromethanopterin (methylene-H4MPT) dehydrogenase (MtdA) catalyzes the reversible dehydrogenation of methylene-H4MPT to form methenyl-H4MPT+ by using NADP+ as a hydride acceptor. This hydride transfer reaction is involved in the oxidative metabolism from formaldehyde to CO2 in methylotrophic and methanotrophic bacteria. Here, we report on the crystal structures of the ternary MtdA-substrate complexes from Methylorubrum extorquens AM1 obtained in open and closed forms. Their conversion is accomplished by opening/closing the active site cleft via a 15° rotation of the NADP, relative to the pterin domain. The 1.08 Å structure of the closed and active enzyme-NADP-methylene-H4MPT complex allows a detailed geometric analysis of the bulky substrates and a precise prediction of the hydride trajectory. Upon domain closure, the bulky substrate rings become compressed resulting in a tilt of the imidazolidine group of methylene-H4MPT that optimizes the geometry for hydride transfer. An additional 1.5 Å structure of MtdA in complex with the nonreactive NADP+ and methenyl-H4MPT+ revealed an extremely short distance between nicotinamide-C4 and imidazoline-C14a of 2.5 Å, which demonstrates the strong pressure imposed. The pterin-imidazolidine-phenyl butterfly angle of methylene-H4MPT bound to MtdA is smaller than that in the enzyme-free state but is similar to that in H2- and F420-dependent methylene-H4MPT dehydrogenases. The concept of compression-driven hydride transfer including quantum mechanical hydrogen tunneling effects, which are established for flavin- and NADP-dependent enzymes, can be expanded to hydride-transferring H4MPT-dependent enzymes.
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20
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Kimata-Ariga Y, Chikuma Y, Saitoh T, Miyata M, Yanagihara Y, Yamane K, Hase T. NADP(H) allosterically regulates the interaction between ferredoxin and ferredoxin-NADP + reductase. FEBS Open Bio 2019; 9:2126-2136. [PMID: 31665566 PMCID: PMC6886308 DOI: 10.1002/2211-5463.12752] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 10/21/2019] [Accepted: 10/28/2019] [Indexed: 11/17/2022] Open
Abstract
Ferredoxin‐NADP+ reductase (FNR) in plants receives electrons from ferredoxin (Fd) at the end of the photosynthetic electron transfer chain and converts NADP+ to NADPH. The interaction between Fd and FNR in plants was previously shown to be attenuated by NADP(H). Here, we investigated the molecular mechanism of this phenomenon using maize FNR and Fd, as the three‐dimensional structure of this complex is available. NADPH, NADP+, and 2′5′‐ADP differentially affected the interaction, as revealed through kinetic and physical binding analyses. Site‐directed mutations of FNR which change the affinity for NADPH altered the affinity for Fd in the opposite direction to that for NADPH. We propose that the binding of NADP(H) causes a conformational change of FNR which is transferred to the Fd‐binding region through different domains of FNR, resulting in allosteric changes in the affinity for Fd. The interaction between ferredoxin (Fd) and Fd‐NADP+ reductase (FNR) in plants is attenuated by NADP(H). Site‐directed mutations of FNR which change the affinity for NADPH altered the affinity for Fd in the opposite direction. We propose that the binding of NADP(H) leads to conformational changes of FNR, resulting in allosteric changes in the affinity for Fd.![]()
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Affiliation(s)
- Yoko Kimata-Ariga
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Japan
| | - Yutaro Chikuma
- Laboratory of Regulation of Biological Reactions, Division of Protein Chemistry, Institute for Protein Research, Osaka University, Suita, Japan
| | - Takashi Saitoh
- Division of Pharmaceutics, Hokkaido Pharmaceutical University School of Pharmacy, Sapporo, Japan
| | - Masayuki Miyata
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Japan
| | - Yuetsu Yanagihara
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Japan
| | - Kazukiyo Yamane
- Department of Biological Chemistry, College of Agriculture, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yoshida, Japan
| | - Toshiharu Hase
- Laboratory of Regulation of Biological Reactions, Division of Protein Chemistry, Institute for Protein Research, Osaka University, Suita, Japan
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21
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Megarity CF, Siritanaratkul B, Cheng B, Morello G, Wan L, Sills AJ, Heath RS, Turner NJ, Armstrong FA. Electrified Nanoconfined Biocatalysis with Rapid Cofactor Recycling. ChemCatChem 2019. [DOI: 10.1002/cctc.201901245] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Clare F. Megarity
- Department of ChemistryUniversity of Oxford South Parks Road Oxford OX1 3QR UK
| | | | - Beichen Cheng
- Department of ChemistryUniversity of Oxford South Parks Road Oxford OX1 3QR UK
| | - Giorgio Morello
- Department of ChemistryUniversity of Oxford South Parks Road Oxford OX1 3QR UK
| | - Lei Wan
- Department of ChemistryUniversity of Oxford South Parks Road Oxford OX1 3QR UK
| | - Adam J. Sills
- Department of ChemistryUniversity of Oxford South Parks Road Oxford OX1 3QR UK
| | - Rachel S. Heath
- School of ChemistryManchester Institute of BiotechnologyUniversity of Manchester 131 Princess Street Manchester M1 7DN UK
| | - Nicholas J. Turner
- School of ChemistryManchester Institute of BiotechnologyUniversity of Manchester 131 Princess Street Manchester M1 7DN UK
| | - Fraser A. Armstrong
- Department of ChemistryUniversity of Oxford South Parks Road Oxford OX1 3QR UK
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22
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Benson DR, Lovell S, Mehzabeen N, Galeva N, Cooper A, Gao P, Battaile KP, Zhu H. Crystal structures of the naturally fused CS and cytochrome b 5 reductase (b 5R) domains of Ncb5or reveal an expanded CS fold, extensive CS-b 5R interactions and productive binding of the NAD(P) + nicotinamide ring. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:628-638. [PMID: 31282472 DOI: 10.1107/s205979831900754x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 05/23/2019] [Indexed: 01/19/2023]
Abstract
Ncb5or (NADH-cytochrome b5 oxidoreductase), a cytosolic ferric reductase implicated in diabetes and neurological diseases, comprises three distinct domains, cytochrome b5 (b5) and cytochrome b5 reductase (b5R) domains separated by a CHORD-Sgt1 (CS) domain, and a novel 50-residue N-terminal region. Understanding how interdomain interactions in Ncb5or facilitate the shuttling of electrons from NAD(P)H to heme, and how the process compares with the microsomal b5 (Cyb5A) and b5R (Cyb5R3) system, is of interest. A high-resolution structure of the b5 domain (PDB entry 3lf5) has previously been reported, which exhibits substantial differences in comparison to Cyb5A. The structural characterization of a construct comprising the naturally fused CS and b5R domains with bound FAD and NAD+ (PDB entry 6mv1) or NADP+ (PDB entry 6mv2) is now reported. The structures reveal that the linker between the CS and b5R cores is more ordered than predicted, with much of it extending the β-sandwich motif of the CS domain. This limits the flexibility between the two domains, which recognize one another via a short β-sheet motif and a network of conserved side-chain hydrogen bonds, salt bridges and cation-π interactions. Notable differences in FAD-protein interactions in Ncb5or and Cyb5R3 provide insight into the selectivity for docking of their respective b5 redox partners. The structures also afford a structural explanation for the unusual ability of Ncb5or to utilize both NADH and NADPH, and represent the first examples of native, fully oxidized b5R family members in which the nicotinamide ring of NAD(P)+ resides in the active site. Finally, the structures, together with sequence alignments, show that the b5R domain is more closely related to single-domain Cyb5R proteins from plants, fungi and some protists than to Cyb5R3 from animals.
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Affiliation(s)
- David R Benson
- Department of Chemistry, The University of Kansas, 1567 Irving Hill Road, Lawrence, KS 66045, USA
| | - Scott Lovell
- Protein Structure Laboratory, The University of Kansas, 2034 Becker Drive, Lawrence, KS 66047, USA
| | - Nurjahan Mehzabeen
- Protein Structure Laboratory, The University of Kansas, 2034 Becker Drive, Lawrence, KS 66047, USA
| | - Nadezhda Galeva
- Analytical Proteomics Laboratory, The University of Kansas, 2034 Becker Drive, Lawrence, KS 66047, USA
| | - Anne Cooper
- Protein Production Group, The University of Kansas, 2034 Becker Drive, Lawrence, KS 66047, USA
| | - Philip Gao
- Protein Production Group, The University of Kansas, 2034 Becker Drive, Lawrence, KS 66047, USA
| | - Kevin P Battaile
- IMCA-CAT, APS, Argonne National Laboratory, 9700 South Cass Avenue, Building 435A, Argonne, IL 60439, USA
| | - Hao Zhu
- Department of Clinical Laboratory Sciences, The University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
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23
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Koskela MM, Dahlström KM, Goñi G, Lehtimäki N, Nurmi M, Velazquez-Campoy A, Hanke G, Bölter B, Salminen TA, Medina M, Mulo P. Arabidopsis FNRL protein is an NADPH-dependent chloroplast oxidoreductase resembling bacterial ferredoxin-NADP + reductases. PHYSIOLOGIA PLANTARUM 2018; 162:177-190. [PMID: 28833218 DOI: 10.1111/ppl.12621] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 08/15/2017] [Indexed: 05/06/2023]
Abstract
Plastidic ferredoxin-NADP+ oxidoreductases (FNRs; EC:1.18.1.2) together with bacterial type FNRs (FPRs) form the plant-type FNR family. Members of this group contain a two-domain scaffold that forms the basis of an extended superfamily of flavin adenine dinucleotide (FAD) dependent oxidoreductases. In this study, we show that the Arabidopsis thaliana At1g15140 [Ferredoxin-NADP+ oxidoreductase-like (FNRL)] is an FAD-containing NADPH dependent oxidoreductase present in the chloroplast stroma. Determination of the kinetic parameters using the DCPIP NADPH-dependent diaphorase assay revealed that the reaction catalysed by a recombinant FNRL protein followed a saturation Michaelis-Menten profile on the NADPH concentration with kcat = 3.2 ± 0.2 s-1 , KmNADPH = 1.6 ± 0.3 μM and kcat /KmNADPH = 2.0 ± 0.4 μM-1 s-1 . Biochemical assays suggested that FNRL is not likely to interact with Arabidopsis ferredoxin 1, which is supported by the sequence analysis implying that the known Fd-binding residues in plastidic FNRs differ from those of FNRL. In addition, based on structural modelling FNRL has an FAD-binding N-terminal domain built from a six-stranded β-sheet and one α-helix, and a C-terminal NADP+ -binding α/β domain with a five-stranded β-sheet with a pair of α-helices on each side. The FAD-binding site is highly hydrophobic and predicted to bind FAD in a bent conformation typically seen in bacterial FPRs.
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Affiliation(s)
- Minna M Koskela
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Käthe M Dahlström
- Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Guillermina Goñi
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Biocomputation and Physics of Complex Systems (BIFI-IQFR and GBsC-CSIC Joint Units), University of Zaragoza, Zaragoza, Spain
| | - Nina Lehtimäki
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Markus Nurmi
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Adrian Velazquez-Campoy
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Biocomputation and Physics of Complex Systems (BIFI-IQFR and GBsC-CSIC Joint Units), University of Zaragoza, Zaragoza, Spain
- Fundación ARAID, Diputación General de Aragón, Zaragoza, Spain
| | - Guy Hanke
- School of Biochemistry and Chemistry, Queen Mary University of London, London, United Kingdom
| | - Bettina Bölter
- Department of Biology I, Botany, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Tiina A Salminen
- Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Milagros Medina
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences and Institute of Biocomputation and Physics of Complex Systems (BIFI-IQFR and GBsC-CSIC Joint Units), University of Zaragoza, Zaragoza, Spain
| | - Paula Mulo
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
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24
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Vorphal MA, Bruna C, Wandersleben T, Dagnino-Leone J, Lobos-González F, Uribe E, Martínez-Oyanedel J, Bunster M. Molecular and functional characterization of ferredoxin NADP(H) oxidoreductase from Gracilaria chilensis and its complex with ferredoxin. Biol Res 2017; 50:39. [PMID: 29221464 PMCID: PMC5723097 DOI: 10.1186/s40659-017-0144-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/04/2017] [Indexed: 12/18/2022] Open
Abstract
Backgroud Ferredoxin NADP(H) oxidoreductases (EC 1.18.1.2) (FNR) are flavoenzymes present in photosynthetic organisms; they are relevant for the production of reduced donors to redox reactions, i.e. in photosynthesis, the reduction of NADP+ to NADPH using the electrons provided by Ferredoxin (Fd), a small FeS soluble protein acceptor of electrons from PSI in chloroplasts. In rhodophyta no information about this system has been reported, this work is a contribution to the molecular and functional characterization of FNR from Gracilaria chilensis, also providing a structural analysis of the complex FNR/Fd. Methods The biochemical and kinetic characterization of FNR was performed from the enzyme purified from phycobilisomes enriched fractions. The sequence of the gene that codifies for the enzyme, was obtained using primers designed by comparison with sequences of Synechocystis and EST from Gracilaria. 5′RACE was used to confirm the absence of a CpcD domain in FNRPBS of Gracilaria chilensis. A three dimensional model for FNR and Fd, was built by comparative modeling and a model for the complex FNR: Fd by docking. Results The kinetic analysis shows KMNADPH of 12.5 M and a kcat of 86 s−1, data consistent with the parameters determined for the enzyme purified from a soluble extract. The sequence for FNR was obtained and translated to a protein of 33646 Da. A FAD and a NADP+ binding domain were clearly identified by sequence analysis as well as a chloroplast signal sequence. Phycobilisome binding domain, present in some cyanobacteria was absent. Transcriptome analysis of Gch revealed the presence of two Fd; FdL and FdS , sharing the motif CX5CX2CX29X. The analysis indicated that the most probable partner for FNR is FdS. Conclusion The interaction model produced, was consistent with functional properties reported for FNR in plants leaves, and opens the possibilities for research in other rhodophyta of commercial interest. Electronic supplementary material The online version of this article (10.1186/s40659-017-0144-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- María Alejandra Vorphal
- Laboratorio de Biofísica Molecular, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160_C, Concepción, Chile
| | - Carola Bruna
- Laboratorio de Biofísica Molecular, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160_C, Concepción, Chile
| | - Traudy Wandersleben
- Laboratorio de Biofísica Molecular, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160_C, Concepción, Chile
| | - Jorge Dagnino-Leone
- Laboratorio de Biofísica Molecular, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160_C, Concepción, Chile
| | - Francisco Lobos-González
- Laboratorio de Biofísica Molecular, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160_C, Concepción, Chile
| | - Elena Uribe
- Laboratorio de Enzimología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160_C, Concepción, Chile
| | - José Martínez-Oyanedel
- Laboratorio de Biofísica Molecular, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160_C, Concepción, Chile.
| | - Marta Bunster
- Laboratorio de Biofísica Molecular, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario S/N, Casilla 160_C, Concepción, Chile.
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25
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Mulo P, Medina M. Interaction and electron transfer between ferredoxin-NADP + oxidoreductase and its partners: structural, functional, and physiological implications. PHOTOSYNTHESIS RESEARCH 2017; 134:265-280. [PMID: 28361449 DOI: 10.1007/s11120-017-0372-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/20/2017] [Indexed: 05/25/2023]
Abstract
Ferredoxin-NADP+ reductase (FNR) catalyzes the last step of linear electron transfer in photosynthetic light reactions. The FAD cofactor of FNR accepts two electrons from two independent reduced ferredoxin molecules (Fd) in two sequential steps, first producing neutral semiquinone and then the fully anionic reduced, or hydroquinone, form of the enzyme (FNRhq). FNRhq transfers then both electrons in a single hydride transfer step to NADP+. We are presenting the recent progress in studies focusing on Fd:FNR interaction and subsequent electron transfer processes as well as on interaction of FNR with NADP+/H followed by hydride transfer, both from the structural and functional point of views. We also present the current knowledge about the physiological role(s) of various FNR isoforms present in the chloroplasts of higher plants and the functional impact of subchloroplastic location of FNR. Moreover, open questions and current challenges about the structure, function, and physiology of FNR are discussed.
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Affiliation(s)
- Paula Mulo
- Molecular Plant Biology, University of Turku, 20520, Turku, Finland
| | - Milagros Medina
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, and Institute of Biocomputation and Physics of Complex Systems (Joint Units: BIFI-IQFR and GBsC-CSIC), University of Zaragoza, 50009, Zaragoza, Spain.
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26
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Expansion of the active site of the azoreductase from Shewanella oneidensis MR-1. J Mol Graph Model 2017; 78:213-220. [DOI: 10.1016/j.jmgm.2017.10.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/27/2017] [Accepted: 10/27/2017] [Indexed: 11/19/2022]
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27
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Grzyb J, Gieczewska K, Łabuz J, Sztatelman O. Detailed characterization of Synechocystis PCC 6803 ferredoxin:NADP + oxidoreductase interaction with model membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:281-291. [PMID: 29038021 DOI: 10.1016/j.bbamem.2017.10.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 10/08/2017] [Accepted: 10/10/2017] [Indexed: 11/15/2022]
Abstract
Direct interaction of ferredoxin:NADP+ oxidoreductase (FNR) with thylakoid membranes was postulated as a part of the cyclic electron flow mechanism. In vitro binding of FNR to digalactosyldiacylglycerol and monogalactosyldiacylglycerol membranes was also shown. In this paper we deal with the latter interaction in more detail describing the effect for two FNR forms of Synechocystis PCC 6803. The so-called short FNR (sFNR) is homologous to FNR from higher plant chloroplasts. The long FNR (lFNR) form contains an additional domain, responsible for the interaction with phycobilisomes. We compare the binding of both sFNR and lFNR forms to native and non-native lipids. We also include factors which could modulate this process: pH change, temperature change, presence of ferredoxin, NADP+ and NADPH and heavy metals. For the lFNR, we also include phycobilisomes as a modulating factor. The membrane binding is generally faster at lower pH. The sFNR was binding faster than lFNR. Ferredoxin isoforms with higher midpoint potential, as well as NADPH and NADP+, weakened the binding. Charged lipids and high phosphate promoted the binding. Heavy metal ions decreased the rate of membrane binding only when FNR was preincubated with them before injection beneath the monolayer. FNR binding was limited to surface lipid groups and did not influence hydrophobic chain packing. Taken together, FNR interaction with lipids appears to be non-specific, with an electrostatic component. This suggests that the direct FNR interaction with lipids is most likely not a factor in directing electron transfer, but should be taken into account during in vitro studies.
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Affiliation(s)
- Joanna Grzyb
- Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, F. Joliot Curie 14a, PL-50383 Wroclaw, Poland; Laboratory of Biological Physics, Institute of Physics Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland.
| | - Katarzyna Gieczewska
- Department of Plant Anatomy and Cytology, Faculty of Biology, University of Warsaw, Miecznikowa 1, PL-02096 Warsaw, Poland; Department of Biophysics, Institute of Physics, Maria Sklodowska-Curie University, M. Sklodowska-Curie sq. 5, PL-20031 Lublin, Poland
| | - Justyna Łabuz
- Laboratory of Photobiology, Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7A, PL-30387 Krakow, Poland
| | - Olga Sztatelman
- Department of Plant Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, PL-02106 Warszawa, Poland
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28
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Bakkes PJ, Riehm JL, Sagadin T, Rühlmann A, Schubert P, Biemann S, Girhard M, Hutter MC, Bernhardt R, Urlacher VB. Engineering of versatile redox partner fusions that support monooxygenase activity of functionally diverse cytochrome P450s. Sci Rep 2017; 7:9570. [PMID: 28852040 PMCID: PMC5575160 DOI: 10.1038/s41598-017-10075-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 08/04/2017] [Indexed: 12/12/2022] Open
Abstract
Most bacterial cytochrome P450 monooxygenases (P450s or CYPs) require two redox partner proteins for activity. To reduce complexity of the redox chain, the Bacillus subtilis flavodoxin YkuN (Y) was fused to the Escherichia coli flavodoxin reductase Fpr (R), and activity was tuned by placing flexible (GGGGS)n or rigid ([E/L]PPPP)n linkers (n = 1–5) in between. P-linker constructs typically outperformed their G-linker counterparts, with superior performance of YR-P5, which carries linker ([E/L]PPPP)5. Molecular dynamics simulations demonstrated that ([E/L]PPPP)n linkers are intrinsically rigid, whereas (GGGGS)n linkers are highly flexible and biochemical experiments suggest a higher degree of separation between the fusion partners in case of long rigid P-linkers. The catalytic properties of the individual redox partners were best preserved in the YR-P5 construct. In comparison to the separate redox partners, YR-P5 exhibited attenuated rates of NADPH oxidation and heme iron (III) reduction, while coupling efficiency was improved (28% vs. 49% coupling with B. subtilis CYP109B1, and 44% vs. 50% with Thermobifida fusca CYP154E1). In addition, YR-P5 supported monooxygenase activity of the CYP106A2 from Bacillus megaterium and bovine CYP21A2. The versatile YR-P5 may serve as a non-physiological electron transfer system for exploitation of the catalytic potential of other P450s.
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Affiliation(s)
- Patrick J Bakkes
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Jan L Riehm
- Center for Bioinformatics, Saarland University, Campus Building E2.1, 66123, Saarbrücken, Germany
| | - Tanja Sagadin
- Institute of Biochemistry, Saarland University, Campus Building B2.2, 66123, Saarbrücken, Germany
| | - Ansgar Rühlmann
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Peter Schubert
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Stefan Biemann
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Marco Girhard
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Michael C Hutter
- Center for Bioinformatics, Saarland University, Campus Building E2.1, 66123, Saarbrücken, Germany
| | - Rita Bernhardt
- Institute of Biochemistry, Saarland University, Campus Building B2.2, 66123, Saarbrücken, Germany
| | - Vlada B Urlacher
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany.
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29
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Kean KM, Carpenter RA, Pandini V, Zanetti G, Hall AR, Faber R, Aliverti A, Karplus PA. High-resolution studies of hydride transfer in the ferredoxin:NADP + reductase superfamily. FEBS J 2017; 284:3302-3319. [PMID: 28783258 DOI: 10.1111/febs.14190] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/28/2017] [Accepted: 08/03/2017] [Indexed: 01/19/2023]
Abstract
Ferredoxin: NADP+ reductase (FNR) is an FAD-containing enzyme best known for catalysing the transfer of electrons from ferredoxin (Fd) to NADP+ to make NADPH during photosynthesis. It is also the prototype for a broad enzyme superfamily, including the NADPH oxidases (NOXs) that all catalyse similar FAD-enabled electron transfers between NAD(P)H and one-electron carriers. Here, we define further mechanistic details of the NAD(P)H ⇌ FAD hydride-transfer step of the reaction based on spectroscopic studies and high-resolution (~ 1.5 Å) crystallographic views of the nicotinamide-flavin interaction in crystals of corn root FNR Tyr316Ser and Tyr316Ala variants soaked with either nicotinamide, NADP+ , or NADPH. The spectra obtained from FNR crystal complexes match those seen in solution and the complexes reveal active site packing interactions and patterns of covalent distortion of the FAD that imply significant active site compression that would favour catalysis. Furthermore, anisotropic B-factors show that the mobility of the C4 atom of the nicotinamide in the FNR:NADP+ complex has a directionality matching that expected for boat-like excursions of the nicotinamide ring thought to enhance hydride transfer. Arguments are made for the relevance of this binding mode to catalysis, and specific consideration is given to how the results extrapolate to provide insight to structure-function relations for the membrane-bound NOX enzymes for which little structural information has been available. DATABASES Structural data are available in the PDB database under the accession numbers 3LO8 (wild-type), 5VW4 [Y316S:nicotinamide (P32 21)], 5VW9 [Y316S:nicotinamide (P31 21)], 5VW3 [Y316S:NADP+ (P32 21)], 5VW8 [Y316S:NADP+ (P31 21)], 5VW2 [Y316S:NADPH (P32 21)], 5VW5 [Y316A:nicotinamide (P32 21)], 5VW6 [Y316A:NADP+ (P32 21)], 5VW7 [Y316A:NADPH (P32 21)], 5VWA [Y316F (P32 21)], and 5VWB [Y316F:NADP+ (P31 21)]. Enzyme Commission number: ferredoxin:NADP+ reductase - E C1.18.1.2.
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Affiliation(s)
- Kelsey M Kean
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Russell A Carpenter
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Vittorio Pandini
- Department of Biosciences, Università degli Studi di Milano, Italy
| | - Giuliana Zanetti
- Department of Biosciences, Università degli Studi di Milano, Italy
| | - Andrea R Hall
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Rick Faber
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | | | - P Andrew Karplus
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
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30
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Abstract
NADPH oxidases (NOXs) are the only enzymes exclusively dedicated to reactive oxygen species (ROS) generation. Dysregulation of these polytopic membrane proteins impacts the redox signaling cascades that control cell proliferation and death. We describe the atomic crystal structures of the catalytic flavin adenine dinucleotide (FAD)- and heme-binding domains of Cylindrospermum stagnale NOX5. The two domains form the core subunit that is common to all seven members of the NOX family. The domain structures were then docked in silico to provide a generic model for the NOX family. A linear arrangement of cofactors (NADPH, FAD, and two membrane-embedded heme moieties) injects electrons from the intracellular side across the membrane to a specific oxygen-binding cavity on the extracytoplasmic side. The overall spatial organization of critical interactions is revealed between the intracellular loops on the transmembrane domain and the NADPH-oxidizing dehydrogenase domain. In particular, the C terminus functions as a toggle switch, which affects access of the NADPH substrate to the enzyme. The essence of this mechanistic model is that the regulatory cues conformationally gate NADPH-binding, implicitly providing a handle for activating/deactivating the very first step in the redox chain. Such insight provides a framework to the discovery of much needed drugs that selectively target the distinct members of the NOX family and interfere with ROS signaling.
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31
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Pitsawong W, Haynes CA, Koder RL, Rodgers DW, Miller AF. Mechanism-Informed Refinement Reveals Altered Substrate-Binding Mode for Catalytically Competent Nitroreductase. Structure 2017; 25:978-987.e4. [PMID: 28578873 DOI: 10.1016/j.str.2017.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 04/02/2017] [Accepted: 05/05/2017] [Indexed: 01/25/2023]
Abstract
Nitroreductase (NR) from Enterobacter cloacae reduces diverse nitroaromatics including herbicides, explosives, and prodrugs, and holds promise for bioremediation, prodrug activation, and enzyme-assisted synthesis. We solved crystal structures of NR complexes with bound substrate or analog for each of its two half-reactions. We complemented these with kinetic isotope effect (KIE) measurements elucidating H-transfer steps essential to each half-reaction. KIEs indicate hydride transfer from NADH to the flavin consistent with our structure of NR with the NADH analog nicotinic acid adenine dinucleotide (NAAD). The KIE on reduction of p-nitrobenzoic acid (p-NBA) also indicates hydride transfer, and requires revision of prior computational mechanisms. Our mechanistic information provided a structural restraint for the orientation of bound substrate, placing the nitro group closer to the flavin N5 in the pocket that binds the amide of NADH. KIEs show that solvent provides a proton, enabling accommodation of different nitro group placements, consistent with the broad repertoire of NR.
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Affiliation(s)
- Warintra Pitsawong
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055, USA
| | - Chad A Haynes
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA
| | - Ronald L Koder
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055, USA
| | - David W Rodgers
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA.
| | - Anne-Frances Miller
- Department of Chemistry, University of Kentucky, 505 Rose Street, Lexington, KY 40506-0055, USA; Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA.
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32
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Acheson JF, Moseson H, Fox BG. Structure of T4moF, the Toluene 4-Monooxygenase Ferredoxin Oxidoreductase. Biochemistry 2015; 54:5980-8. [PMID: 26309236 DOI: 10.1021/acs.biochem.5b00692] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 1.6 Å crystal structure of toluene 4-monooxygenase reductase T4moF is reported. The structure includes ferredoxin, flavin, and NADH binding domains. The position of the ferredoxin domain relative to the other two domains represents a new configuration for the iron-sulfur flavoprotein family. Close contacts between the C8 methyl group of FAD and [2Fe-2S] ligand Cys36-O represent a plausible pathway for electron transfer between the redox cofactors. Energy-minimized docking of NADH and calculation of hingelike motions between domains suggest how simple coordinated shifts of residues at the C-terminus of the enzyme could expose the N5 position of FAD for productive interaction with the nicotinamide ring. The domain configuration revealed by the T4moF structure provides an excellent steric and electrostatic match to the obligate electron acceptor, Rieske-type [2Fe-2S] ferredoxin T4moC. Protein-protein docking and energy minimization of the T4moFC complex indicate that T4moF [2Fe-2S] ligand Cys41 and T4moC [2Fe-2S] ligand His67, along with other electrostatic interactions between the protein partners, form the functional electron transfer interface.
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Affiliation(s)
- Justin F Acheson
- Department of Biochemistry, College of Agriculture and Life Sciences, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Hannah Moseson
- Department of Biochemistry, College of Agriculture and Life Sciences, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Brian G Fox
- Department of Biochemistry, College of Agriculture and Life Sciences, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
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33
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Mutoh R, Muraki N, Shinmura K, Kubota-Kawai H, Lee YH, Nowaczyk MM, Rögner M, Hase T, Ikegami T, Kurisu G. X-ray Structure and Nuclear Magnetic Resonance Analysis of the Interaction Sites of the Ga-Substituted Cyanobacterial Ferredoxin. Biochemistry 2015; 54:6052-61. [DOI: 10.1021/acs.biochem.5b00601] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Risa Mutoh
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka,
Suita, Osaka 565-0871, Japan
- Core
Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
| | - Norifumi Muraki
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka,
Suita, Osaka 565-0871, Japan
| | - Kanako Shinmura
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka,
Suita, Osaka 565-0871, Japan
| | - Hisako Kubota-Kawai
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka,
Suita, Osaka 565-0871, Japan
- Core
Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
| | - Young-Ho Lee
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka,
Suita, Osaka 565-0871, Japan
| | - Marc M. Nowaczyk
- Plant
Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Matthias Rögner
- Plant
Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Toshiharu Hase
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka,
Suita, Osaka 565-0871, Japan
| | - Takahisa Ikegami
- Department
of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
- Core
Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
| | - Genji Kurisu
- Institute
for Protein Research, Osaka University, 3-2 Yamadaoka,
Suita, Osaka 565-0871, Japan
- Core
Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
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34
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Whitelaw DA, Tonkin R, Meints CE, Wolthers KR. Kinetic analysis of electron flux in cytochrome P450 reductases reveals differences in rate-determining steps in plant and mammalian enzymes. Arch Biochem Biophys 2015; 584:107-15. [PMID: 26361974 DOI: 10.1016/j.abb.2015.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/02/2015] [Accepted: 09/03/2015] [Indexed: 11/19/2022]
Abstract
Herein, we compare the kinetic properties of CPR from Arabidopsis thaliana (ATR2), with CPR from Artemisia annua (aaCPR) and human CPR (hCPR). While all three CPR forms elicit comparable rates for cytochrome c(3+) turnover, NADPH reduction of the FAD cofactor is ∼50-fold faster in aaCPR and ATR2 compared to hCPR, with a kobs of ∼500 s(-1) (6 °C). Stopped-flow analysis of the isolated FAD-domains reveals that NADP(+)-FADH2 charge-transfer complex formation is also significantly faster in the plant enzymes, but the rate of its decay is comparable for all three proteins. In hCPR, transfer of a hydride ion from NADPH to FAD is tightly coupled to subsequent FAD to FMN electron transfer, indicating that the former catalytic event is slow relative to the latter. In contrast, interflavin electron transfer is slower than NADPH hydride transfer in aaCPR and ATR2, occurring with an observed rate constant of ∼50 s(-1). Finally, the transfer of electrons from FMN to cytochrome c(3+) is rapid (>10(3) s(-1)) in all three enzymes and does not limit catalytic turnover. In combination, the data reveal differences in rate-determining steps between plant CPR and their mammalian equivalent in mediating the flux of reducing equivalents from NADPH to external electron acceptors.
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Affiliation(s)
- Douglas A Whitelaw
- Department of Chemistry, University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna BC, V1V 1V7, Canada
| | - Rochelle Tonkin
- Department of Chemistry, University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna BC, V1V 1V7, Canada
| | - Carla E Meints
- Department of Chemistry, University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna BC, V1V 1V7, Canada
| | - Kirsten R Wolthers
- Department of Chemistry, University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna BC, V1V 1V7, Canada.
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Bakkes PJ, Biemann S, Bokel A, Eickholt M, Girhard M, Urlacher VB. Design and improvement of artificial redox modules by molecular fusion of flavodoxin and flavodoxin reductase from Escherichia coli. Sci Rep 2015; 5:12158. [PMID: 26177696 PMCID: PMC4503991 DOI: 10.1038/srep12158] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 06/19/2015] [Indexed: 11/09/2022] Open
Abstract
A variety of fusion proteins between the versatile redox partners flavodoxin (FldA) and flavodoxin reductase (Fpr) from Escherichia coli was constructed with the aim to improve the electron transfer properties. The order in which FldA and Fpr were fused and the linker region between them was varied in a systematic manner. A simple molecular tool, designated "DuaLinX", was developed that facilitated the parallel introduction of flexible glycine-rich and rigid proline-rich linkers between the fusion partners in a single cloning event. The fusion constructs were tested for their ability to transfer electrons to cytochrome c and cytochrome P450 109B1 from Bacillus subtilis. With CYP109B1, the performance of the constructs showed, independent of the domain order, a strong dependency on linker length, whereas with cytochrome c this phenomenon was less pronounced. Constructs carrying linkers of ≥15 residues effectively supported the CYP109B1-catalysed hydroxylation of myristic acid. Constructs carrying proline-rich linkers generally outperformed their glycine-rich counterparts. The best construct, FldA-Fpr carrying linker ([E/L]PPPP)4, supported CYP109B1 activity equally well as equivalent amounts of the non-fused redox partners, while cytochrome c reductase activity was ~2.7-fold improved. Thus, to functionally connect redox partners, rigid proline-rich linkers may be attractive alternatives to the commonly used flexible glycine-rich linkers.
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Affiliation(s)
- Patrick J Bakkes
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Stefan Biemann
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Ansgar Bokel
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Marc Eickholt
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Marco Girhard
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Vlada B Urlacher
- Institute of Biochemistry, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
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36
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Hamdane D, Bou-Nader C, Cornu D, Hui-Bon-Hoa G, Fontecave M. Flavin-Protein Complexes: Aromatic Stacking Assisted by a Hydrogen Bond. Biochemistry 2015; 54:4354-64. [PMID: 26120776 DOI: 10.1021/acs.biochem.5b00501] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Enzyme-catalyzed reactions often rely on a noncovalently bound cofactor whose reactivity is tuned by its immediate environment. Flavin cofactors, the most versatile catalyst encountered in biology, are often maintained within the protein throughout numbers of complex ionic and aromatic interactions. Here, we have investigated the role of π-π stacking and hydrogen bond interactions between a tyrosine and the isoalloxazine moiety of the flavin adenine dinucleotide (FAD) in an FAD-dependent RNA methyltransferase. Combining several static and time-resolved spectroscopies as well as biochemical approaches, we showed that aromatic stacking is assisted by a hydrogen bond between the phenol group and the amide of an adjacent active site loop. A mechanism of recognition and binding of the redox cofactor is proposed.
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Affiliation(s)
- Djemel Hamdane
- †Laboratoire de Chimie des Processus Biologiques, CNRS-UMR 8229, Collège De France, France 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Charles Bou-Nader
- †Laboratoire de Chimie des Processus Biologiques, CNRS-UMR 8229, Collège De France, France 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - David Cornu
- ‡INSERM U779, 78 Rue du Général Leclerc, 94275 Le Kremlin-Bicêtre, France
| | - Gaston Hui-Bon-Hoa
- §Plateforme IMAGIF, Centre de Recherche de Gif, Centre National de la Recherche Scientifique, 1 avenue de le terrasse, 91191 Gif Sur Yvette, France
| | - Marc Fontecave
- †Laboratoire de Chimie des Processus Biologiques, CNRS-UMR 8229, Collège De France, France 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France
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Demmer JK, Huang H, Wang S, Demmer U, Thauer RK, Ermler U. Insights into Flavin-based Electron Bifurcation via the NADH-dependent Reduced Ferredoxin:NADP Oxidoreductase Structure. J Biol Chem 2015; 290:21985-95. [PMID: 26139605 DOI: 10.1074/jbc.m115.656520] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Indexed: 11/06/2022] Open
Abstract
NADH-dependent reduced ferredoxin:NADP oxidoreductase (NfnAB) is found in the cytoplasm of various anaerobic bacteria and archaea. The enzyme reversibly catalyzes the endergonic reduction of ferredoxin with NADPH driven by the exergonic transhydrogenation from NADPH onto NAD(+). Coupling is most probably accomplished via the mechanism of flavin-based electron bifurcation. To understand this process on a structural basis, we heterologously produced the NfnAB complex of Thermotoga maritima in Escherichia coli, provided kinetic evidence for its bifurcating behavior, and determined its x-ray structure in the absence and presence of NADH. The structure of NfnAB reveals an electron transfer route including the FAD (a-FAD), the [2Fe-2S] cluster of NfnA and the FAD (b-FAD), and the two [4Fe-4S] clusters of NfnB. Ferredoxin is presumably docked onto NfnB close to the [4Fe-4S] cluster distal to b-FAD. NAD(H) binds to a-FAD and NADP(H) consequently to b-FAD, which is positioned in the center of the NfnAB complex and the site of electron bifurcation. Arg(187) is hydrogen-bonded to N5 and O4 of the bifurcating b-FAD and might play a key role in adjusting a low redox potential of the FADH(•)/FAD pair required for ferredoxin reduction. A mechanism of FAD-coupled electron bifurcation by NfnAB is proposed.
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Affiliation(s)
- Julius K Demmer
- From the Max-Planck-Institut für Biophysik, D-60438 Frankfurt am Main, Germany and the Max-Planck-Institut für Terrestrische Mikrobiologie, D-35043 Marburg, Germany
| | - Haiyan Huang
- the Max-Planck-Institut für Terrestrische Mikrobiologie, D-35043 Marburg, Germany
| | - Shuning Wang
- the Max-Planck-Institut für Terrestrische Mikrobiologie, D-35043 Marburg, Germany
| | - Ulrike Demmer
- From the Max-Planck-Institut für Biophysik, D-60438 Frankfurt am Main, Germany and
| | - Rudolf K Thauer
- the Max-Planck-Institut für Terrestrische Mikrobiologie, D-35043 Marburg, Germany
| | - Ulrich Ermler
- From the Max-Planck-Institut für Biophysik, D-60438 Frankfurt am Main, Germany and
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38
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Rahaman MM, Reinders FG, Koes D, Nguyen AT, Mutchler SM, Sparacino-Watkins C, Alvarez RA, Miller MP, Cheng D, Chen BB, Jackson EK, Camacho CJ, Straub AC. Structure Guided Chemical Modifications of Propylthiouracil Reveal Novel Small Molecule Inhibitors of Cytochrome b5 Reductase 3 That Increase Nitric Oxide Bioavailability. J Biol Chem 2015; 290:16861-72. [PMID: 26001785 DOI: 10.1074/jbc.m114.629964] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Indexed: 11/06/2022] Open
Abstract
NADH cytochrome b5 reductase 3 (CYB5R3) is critical for reductive reactions such as fatty acid elongation, cholesterol biosynthesis, drug metabolism, and methemoglobin reduction. Although the physiological and metabolic importance of CYB5R3 has been established in hepatocytes and erythrocytes, emerging investigations suggest that CYB5R3 is critical for nitric oxide signaling and vascular function. However, advancement toward fully understanding CYB5R3 function has been limited due to a lack of potent small molecule inhibitors. Because of this restriction, we modeled the binding mode of propylthiouracil, a weak inhibitor of CYB5R3 (IC50 = ∼275 μM), and used it as a guide to predict thiouracil-biased inhibitors from the set of commercially available compounds in the ZINC database. Using this approach, we validated two new potent derivatives of propylthiouracil, ZINC05626394 (IC50 = 10.81 μM) and ZINC39395747 (IC50 = 9.14 μM), both of which inhibit CYB5R3 activity in cultured cells. Moreover, we found that ZINC39395747 significantly increased NO bioavailability in renal vascular cells, augmented renal blood flow, and decreased systemic blood pressure in response to vasoconstrictors in spontaneously hypertensive rats. These compounds will serve as a new tool to examine the biological functions of CYB5R3 in physiology and disease and also as a platform for new drug development.
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Affiliation(s)
| | | | - David Koes
- Department of Computational and Systems Biology
| | - Anh T Nguyen
- From the Heart, Lung, Blood, and Vascular Medicine Institute
| | - Stephanie M Mutchler
- From the Heart, Lung, Blood, and Vascular Medicine Institute, Department of Pharmacology and Chemical Biology, and
| | | | - Roger A Alvarez
- From the Heart, Lung, Blood, and Vascular Medicine Institute, Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Megan P Miller
- From the Heart, Lung, Blood, and Vascular Medicine Institute
| | - Dongmei Cheng
- Department of Pharmacology and Chemical Biology, and
| | - Bill B Chen
- Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | | | | | - Adam C Straub
- From the Heart, Lung, Blood, and Vascular Medicine Institute, Department of Pharmacology and Chemical Biology, and
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Lehtimäki N, Koskela MM, Dahlström KM, Pakula E, Lintala M, Scholz M, Hippler M, Hanke GT, Rokka A, Battchikova N, Salminen TA, Mulo P. Posttranslational modifications of FERREDOXIN-NADP+ OXIDOREDUCTASE in Arabidopsis chloroplasts. PLANT PHYSIOLOGY 2014; 166:1764-76. [PMID: 25301888 PMCID: PMC4256869 DOI: 10.1104/pp.114.249094] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Rapid responses of chloroplast metabolism and adjustments to photosynthetic machinery are of utmost importance for plants' survival in a fluctuating environment. These changes may be achieved through posttranslational modifications of proteins, which are known to affect the activity, interactions, and localization of proteins. Recent studies have accumulated evidence about the crucial role of a multitude of modifications, including acetylation, methylation, and glycosylation, in the regulation of chloroplast proteins. Both of the Arabidopsis (Arabidopsis thaliana) leaf-type FERREDOXIN-NADP(+) OXIDOREDUCTASE (FNR) isoforms, the key enzymes linking the light reactions of photosynthesis to carbon assimilation, exist as two distinct forms with different isoelectric points. We show that both AtFNR isoforms contain multiple alternative amino termini and undergo light-responsive addition of an acetyl group to the α-amino group of the amino-terminal amino acid of proteins, which causes the change in isoelectric point. Both isoforms were also found to contain acetylation of a conserved lysine residue near the active site, while no evidence for in vivo phosphorylation or glycosylation was detected. The dynamic, multilayer regulation of AtFNR exemplifies the complex regulatory network systems controlling chloroplast proteins by a range of posttranslational modifications, which continues to emerge as a novel area within photosynthesis research.
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Affiliation(s)
- Nina Lehtimäki
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Minna M Koskela
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Käthe M Dahlström
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Eveliina Pakula
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Minna Lintala
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Martin Scholz
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Michael Hippler
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Guy T Hanke
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Anne Rokka
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Natalia Battchikova
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Tiina A Salminen
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
| | - Paula Mulo
- Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20520 Turku, Finland (N.L., M.M.K., E.P., M.L., N.B., P.M.);Structural Bioinformatics Laboratory, Department of Biosciences, Åbo Akademi University, FI-20520 Turku, Finland (K.M.D., T.A.S.);Institute of Plant Biology and Biotechnology, Faculty of Biology, Westfälische Wilhelms-Universität Münster, DE-48143 Muenster, Germany (M.S., M.H.);Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076 Osnabruck, Germany (G.T.H.); andTurku Centre for Biotechnology, FI-20520 Turku, Finland (A.R.)
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40
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Dynamics of the active site architecture in plant-type ferredoxin-NADP+ reductases catalytic complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1730-8. [DOI: 10.1016/j.bbabio.2014.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/05/2014] [Accepted: 06/11/2014] [Indexed: 12/24/2022]
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41
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Characterization of the mechanism of the NADH-dependent polysulfide reductase (Npsr) from Shewanella loihica PV-4: formation of a productive NADH-enzyme complex and its role in the general mechanism of NADH and FAD-dependent enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1708-17. [PMID: 24981797 DOI: 10.1016/j.bbapap.2014.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 05/26/2014] [Accepted: 06/18/2014] [Indexed: 11/20/2022]
Abstract
The NADH-dependent polysulfide reductase (Npsr) from Shewanella loihica PV-4 is a member of the single cysteine-containing subset of the family of disulfide reductases represented by glutathione reductase. We have determined the kinetics of the reductive half-reaction of the enzyme with NADH using stopped-flow spectroscopy and kinetic isotope effects, and these results indicate that the reductive and oxidative half-reactions are both partially rate-limiting for enzyme turnover. During reaction with NADH, the reduced nucleotide appears to bind rapidly in an unproductive conformation, followed by the formation of a productive E·NADH complex and subsequent electron transfer to FAD. F161 of Npsr fills the space in which the nicotinamide ring of NADH would be expected to bind. We have shown that while this residue is not absolutely required for catalysis, it does assist in the forward commitment to catalysis through its role in the reductive half reaction, where it appears to enhance hydride transfer in the productive E·NADH complex. While the fluorescence and absorbance spectra of the stable redox forms of the wild-type and F161A mutant enzymes are similar, intermediates formed during reduction and turnover have different characteristics and appear to indicate that the enzyme-NADH complex formed just prior to hydride transfer on the F161A enzyme has weaker FAD-NADH interactions than the wild-type enzyme, consistent with a "looser" enzyme-NADH complex. The 2.7Å crystal structure of the F161A mutant was determined, and shows that the nicotinamide ring of NADH would have the expected freedom of motion in the more open NADH binding cavity.
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42
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Ferreira P, Martínez-Júlvez M, Medina M. Electron transferases. Methods Mol Biol 2014; 1146:79-94. [PMID: 24764089 DOI: 10.1007/978-1-4939-0452-5_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The flavin isoalloxazine ring in electron transferases functions in a redox capacity, being able to take up electrons from a donor to subsequently deliver them to an acceptor. The main characteristics of these flavoproteins, including their unique ability to mediate obligatory processes of two-electron transfers with those involving single-electron transfer, are here described. To illustrate the versatility of these proteins, the acquired knowledge of the function of the two electron transferases involved in the cyanobacterial photosynthetic electron transfer from photosystem I to NADP(+) is presented. Many aspects of their biochemistry and biophysics have been extensively characterized using site-directed mutagenesis, steady-state and transient kinetics, spectroscopy, calorimetry, X-ray crystallography, electron paramagnetic resonance, and computational methods.
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Affiliation(s)
- Patricia Ferreira
- Department of Biochemistry and Molecular and Cellular Biology, Institute for Biocomputation and Physics of Complex Systems, Zaragoza, Spain
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43
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Meints CE, Parke SM, Wolthers KR. Proximal FAD histidine residue influences interflavin electron transfer in cytochrome P450 reductase and methionine synthase reductase. Arch Biochem Biophys 2014; 547:18-26. [PMID: 24589657 DOI: 10.1016/j.abb.2014.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/17/2014] [Accepted: 02/19/2014] [Indexed: 10/25/2022]
Abstract
Cytochrome P450 reductase (CPR) and methionine synthase reductase (MSR) transfer reducing equivalents from NADPH to FAD to FMN. In CPR, hydride transfer and interflavin electron transfer are kinetically coupled steps, but in MSR the two catalytic steps are represented by two distinct kinetic phases leading to transient formation of the FAD hydroquinone. In human CPR, His(322) forms a hydrogen-bond with the highly conserved Asp(677), a member of the catalytic triad. The catalytic triad is present in MSR, but Ala(312) replaces the histidine residue. To examine if this structural variation accounts for differences in their kinetic behavior, reciprocal substitutions were created. Substitution of His(322) for Ala in CPR does not affect the rate of NADPH hydride transfer or the FAD redox potentials, but does impede interflavin electron transfer. For MSR, swapping Ala(312) for a histidine residue resulted in the kinetic coupling of hydride and interflavin electron transfer, and eliminated the formation of the FAD hydroquinone intermediate. For both enzymes, placement of the His residue in the active site weakens coenzyme binding affinity. The data suggest that the proximal FAD histidine residue accelerates proton-coupled electron transfer from FADH2 to the higher potential FMN; a mechanism for this catalytic role is discussed.
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Affiliation(s)
- Carla E Meints
- Department of Chemistry, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC V1V 1V7, Canada
| | - Sarah M Parke
- Department of Chemistry, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC V1V 1V7, Canada
| | - Kirsten R Wolthers
- Department of Chemistry, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
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44
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Sánchez-Azqueta A, Herguedas B, Hurtado-Guerrero R, Hervás M, Navarro JA, Martínez-Júlvez M, Medina M. A hydrogen bond network in the active site of Anabaena ferredoxin-NADP+ reductase modulates its catalytic efficiency. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:251-63. [DOI: 10.1016/j.bbabio.2013.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 10/13/2013] [Accepted: 10/23/2013] [Indexed: 10/26/2022]
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45
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Antonini LV, Peregrina JR, Angulo J, Medina M, Nieto PM. A STD-NMR study of the interaction of the Anabaena ferredoxin-NADP+ reductase with the coenzyme. Molecules 2014; 19:672-85. [PMID: 24402199 PMCID: PMC6272016 DOI: 10.3390/molecules19010672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/17/2013] [Accepted: 12/18/2013] [Indexed: 11/16/2022] Open
Abstract
Ferredoxin-NADP+ reductase (FNR) catalyzes the electron transfer from ferredoxin to NADP+ via its flavin FAD cofactor. To get further insights in the architecture of the transient complexes produced during the hydride transfer event between the enzyme and the NADP+ coenzyme we have applied NMR spectroscopy using Saturation Transfer Difference (STD) techniques to analyze the interaction between FNRox and the oxidized state of its NADP+ coenzyme. We have found that STD NMR, together with the use of selected mutations on FNR and of the non-FNR reacting coenzyme analogue NAD+, are appropriate tools to provide further information about the the interaction epitope.
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Affiliation(s)
- Lara V Antonini
- Instituto de Investigaciones Químicas, CSIC, Americo Vespucio, 49, Sevilla 41092, Spain.
| | - José R Peregrina
- Instituto de Investigaciones Químicas, CSIC, Americo Vespucio, 49, Sevilla 41092, Spain.
| | - Jesús Angulo
- Instituto de Investigaciones Químicas, CSIC, Americo Vespucio, 49, Sevilla 41092, Spain.
| | - Milagros Medina
- Instituto de Investigaciones Químicas, CSIC, Americo Vespucio, 49, Sevilla 41092, Spain.
| | - Pedro M Nieto
- Instituto de Investigaciones Químicas, CSIC, Americo Vespucio, 49, Sevilla 41092, Spain.
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External loops at the ferredoxin-NADP(+) reductase protein-partner binding cavity contribute to substrates allocation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:296-305. [PMID: 24321506 DOI: 10.1016/j.bbabio.2013.11.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 11/20/2013] [Accepted: 11/27/2013] [Indexed: 11/24/2022]
Abstract
Ferredoxin-NADP(+) reductase (FNR) is the structural prototype of a family of FAD-containing reductases that catalyze electron transfer between low potential proteins and NAD(P)(+)/H, and that display a two-domain arrangement with an open cavity at their interface. The inner part of this cavity accommodates the reacting atoms during catalysis. Loops at its edge are highly conserved among plastidic FNRs, suggesting that they might contribute to both flavin stabilization and competent disposition of substrates. Here we pay attention to two of these loops in Anabaena FNR. The first is a sheet-loop-sheet motif, loop102-114, that allocates the FAD adenosine. It was thought to determine the extended FAD conformation, and, indirectly, to modulate isoalloxazine electronic properties, partners binding, catalytic efficiency and even coenzyme specificity. The second, loop261-269, contains key residues for the allocation of partners and coenzyme, including two glutamates, Glu267 and Glu268, proposed as candidates to facilitate the key displacement of the C-terminal tyrosine (Tyr303) from its stacking against the isoalloxazine ring during the catalytic cycle. Our data indicate that the main function of loop102-114 is to provide the inter-domain cavity with flexibility to accommodate protein partners and to guide the coenzyme to the catalytic site, while the extended conformation of FAD must be induced by other protein determinants. Glu267 and Glu268 appear to assist the conformational changes that occur in the loop261-269 during productive coenzyme binding, but their contribution to Tyr303 displacement is minor than expected. Additionally, loop261-269 appears a determinant to ensure reversibility in photosynthetic FNRs.
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Simtchouk S, Eng JL, Meints CE, Makins C, Wolthers KR. Kinetic analysis of cytochrome P450 reductase from Artemisia annua reveals accelerated rates of NADH-dependent flavin reduction. FEBS J 2013; 280:6627-42. [PMID: 24299267 DOI: 10.1111/febs.12567] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 09/06/2013] [Accepted: 10/09/2013] [Indexed: 11/26/2022]
Abstract
Cytochrome P450 reductase from Artemisia annua (aaCPR) is a diflavin enzyme that has been employed for the microbial synthesis of artemisinic acid (a semi-synthetic precursor of the anti-malarial drug, artemisinin) based on its ability to transfer electrons to the cytochrome P450 monooxygenase, CYP71AV1. We have isolated recombinant aaCPR (with the N-terminal transmembrane motif removed) from Escherichia coli and compared its kinetic and thermodynamic properties with other CPR orthologues, most notably human CPR. The FAD and FMN redox potentials and the macroscopic kinetic constants associated with cytochrome c(3+) reduction for aaCPR are comparable to that of other CPR orthologues, with the exception that the apparent binding affinity for the oxidized coenzyme is ~ 30-fold weaker compared to human CPR. CPR from A. annua shows a 3.5-fold increase in uncoupled NADPH oxidation compared to human CPR and a strong preference (85 100-fold) for NADPH over NADH. Strikingly, reduction of the enzyme by the first and second equivalent of NADPH is much faster in aaCPR, with rates of > 500 and 17 s(-1) at 6 °C. We also optically detect a charge-transfer species that rapidly forms in < 3 ms and then persists during the reductive half reaction. Additional stopped-flow kinetic studies with NADH and (R)-[4-(2) H]NADPH suggest that the accelerated rate of flavin reduction is attributed to the relatively weak binding affinity of aaCPR for NADP(+) .
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Affiliation(s)
- Svetlana Simtchouk
- Department of Chemistry, University of British Columbia, Kelowna, BC, Canada
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48
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Yamada M, Tamada T, Takeda K, Matsumoto F, Ohno H, Kosugi M, Takaba K, Shoyama Y, Kimura S, Kuroki R, Miki K. Elucidations of the catalytic cycle of NADH-cytochrome b5 reductase by X-ray crystallography: new insights into regulation of efficient electron transfer. J Mol Biol 2013; 425:4295-306. [PMID: 23831226 DOI: 10.1016/j.jmb.2013.06.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/18/2013] [Accepted: 06/12/2013] [Indexed: 10/26/2022]
Abstract
NADH-Cytochrome b5 reductase (b5R), a flavoprotein consisting of NADH and flavin adenine dinucleotide (FAD) binding domains, catalyzes electron transfer from the two-electron carrier NADH to the one-electron carrier cytochrome b5 (Cb5). The crystal structures of both the fully reduced form and the oxidized form of porcine liver b5R were determined. In the reduced b5R structure determined at 1.68Å resolution, the relative configuration of the two domains was slightly shifted in comparison with that of the oxidized form. This shift resulted in an increase in the solvent-accessible surface area of FAD and created a new hydrogen-bonding interaction between the N5 atom of the isoalloxazine ring of FAD and the hydroxyl oxygen atom of Thr66, which is considered to be a key residue in the release of a proton from the N5 atom. The isoalloxazine ring of FAD in the reduced form is flat as in the oxidized form and stacked together with the nicotinamide ring of NAD(+). Determination of the oxidized b5R structure, including the hydrogen atoms, determined at 0.78Å resolution revealed the details of a hydrogen-bonding network from the N5 atom of FAD to His49 via Thr66. Both of the reduced and oxidized b5R structures explain how backflow in this catalytic cycle is prevented and the transfer of electrons to one-electron acceptors such as Cb5 is accelerated. Furthermore, crystallographic analysis by the cryo-trapping method suggests that re-oxidation follows a two-step mechanism. These results provide structural insights into the catalytic cycle of b5R.
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Affiliation(s)
- Mitsugu Yamada
- Molecular Biology Research Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Ibaraki 319-1195, Japan
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49
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Hanke G, Mulo P. Plant type ferredoxins and ferredoxin-dependent metabolism. PLANT, CELL & ENVIRONMENT 2013; 36:1071-1084. [PMID: 23190083 DOI: 10.1111/pce.12046] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 11/19/2012] [Accepted: 11/20/2012] [Indexed: 05/24/2023]
Abstract
Ferredoxin (Fd) is a small [2Fe-2S] cluster-containing protein found in all organisms performing oxygenic photosynthesis. Fd is the first soluble acceptor of electrons on the stromal side of the chloroplast electron transport chain, and as such is pivotal to determining the distribution of these electrons to different metabolic reactions. In chloroplasts, the principle sink for electrons is in the production of NADPH, which is mostly consumed during the assimilation of CO2 . In addition to this primary function in photosynthesis, Fds are also involved in a number of other essential metabolic reactions, including biosynthesis of chlorophyll, phytochrome and fatty acids, several steps in the assimilation of sulphur and nitrogen, as well as redox signalling and maintenance of redox balance via the thioredoxin system and Halliwell-Asada cycle. This makes Fds crucial determinants of the electron transfer between the thylakoid membrane and a variety of soluble enzymes dependent on these electrons. In this article, we will first describe the current knowledge on the structure and function of the various Fd isoforms present in chloroplasts of higher plants and then discuss the processes involved in oxidation of Fd, introducing the corresponding enzymes and discussing what is known about their relative interaction with Fd.
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Affiliation(s)
- Guy Hanke
- Plant Physiology, Faculty of Biology and Chemistry, University of Osnabrück, DE-49076, Osnabrück, Germany
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50
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Meints CE, Simtchouk S, Wolthers KR. Aromatic substitution of the FAD-shielding tryptophan reveals its differential role in regulating electron flux in methionine synthase reductase and cytochrome P450 reductase. FEBS J 2013; 280:1460-74. [PMID: 23332101 DOI: 10.1111/febs.12141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/27/2012] [Accepted: 01/15/2013] [Indexed: 11/30/2022]
Abstract
Methionine synthase reductase (MSR) and cytochrome P450 reductase (CPR) transfer reducing equivalents from NADPH via an FAD and FMN cofactor to a redox partner protein. In both enzymes, hydride transfer from NADPH to FAD requires displacement of a conserved tryptophan that lies coplanar to the FAD isoalloxazine ring. Swapping the tryptophan for a smaller aromatic side chain revealed a distinct role for the residue in regulating MSR and CPR catalysis. MSR W697F and W697Y showed enhanced catalysis, noted by increases in kcat and k(cat)/K(m)(NADPH) for steady-state cytochrome c(3+) reduction and a 10-fold increase in the rate constant (k(obs1)) associated with hydride transfer. Elevated primary kinetic isotope effects on k(obs1) for W697F and W697Y suggest that preceding isotopically insensitive steps like displacement of W697 are less rate determining. MSR W697Y, but not MSR W697F, showed detectable formation of the disemiquinone intermediate, indicating that the polarity of the aromatic side chain influences the rate of interflavin electron transfer. By contrast, the CPR variants (W676F and W676Y) displayed modest decreases in cytochrome c(3+) reduction, a 30- and 3.5-fold decrease in the rate of FAD reduction, accumulation of a FADH2 -NADP(+) charge-transfer complex and dramatically suppressed rates of interflavin electron transfer. We conclude for MSR that hydride transfer is 'gated' by the free energy required to disrupt dispersion forces between the FAD isoalloxazine ring and W697. By contrast, the bulky indole ring of W676 accelerates catalysis in CPR by lowering the energy barrier for displacement of the oxidized nicotinamide ring coplanar with the FAD.
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Affiliation(s)
- Carla E Meints
- Department of Chemistry, University of British Columbia Okanagan, Kelowna, BC, Canada
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