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van Wonderen JH, Crack JC, Edwards MJ, Clarke TA, Saalbach G, Martins C, Butt JN. Liquid-chromatography mass spectrometry describes post-translational modification of Shewanella outer membrane proteins. Biochim Biophys Acta Biomembr 2024; 1866:184221. [PMID: 37673350 DOI: 10.1016/j.bbamem.2023.184221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 08/09/2023] [Accepted: 08/30/2023] [Indexed: 09/08/2023]
Abstract
Electrogenic bacteria deliver excess respiratory electrons to externally located metal oxide particles and electrodes. The biochemical basis for this process is arguably best understood for species of Shewanella where the integral membrane complex termed MtrCAB is key to electron transfer across the bacterial outer membranes. A crystal structure was recently resolved for MtrCAB from S. baltica OS185. However, X-ray diffraction did not resolve the N-terminal residues so that the lipidation status of proteins in the mature complex was poorly described. Here we report liquid chromatography mass spectrometry revealing the intact mass values for all three proteins in the MtrCAB complexes purified from Shewanella oneidensis MR-1 and S. baltica OS185. The masses of MtrA and MtrB are consistent with both proteins being processed by Signal Peptidase I and covalent attachment of ten c-type hemes to MtrA. The mass of MtrC is most reasonably interpreted as arising from protein processed by Signal Peptidase II to produce a diacylated lipoprotein containing ten c-type hemes. Our two-step protocol for liquid-chromatography mass spectrometry used a reverse phase column to achieve on-column detergent removal prior to gradient protein resolution and elution. We envisage the method will be capable of simultaneously resolving the intact mass values for multiple proteins in other membrane protein complexes.
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Affiliation(s)
- Jessica H van Wonderen
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
| | - Jason C Crack
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Marcus J Edwards
- School of Biological Sciences, University of East Anglia, , Norwich Research Park, Norwich NR4 7TJ, UK; School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
| | - Thomas A Clarke
- School of Biological Sciences, University of East Anglia, , Norwich Research Park, Norwich NR4 7TJ, UK
| | - Gerhard Saalbach
- Proteomics Facility, The John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Carlo Martins
- Proteomics Facility, The John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Julea N Butt
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK; School of Biological Sciences, University of East Anglia, , Norwich Research Park, Norwich NR4 7TJ, UK.
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2
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Izzo M, Osella S, Jacquet M, Kiliszek M, Harputlu E, Starkowska A, Łasica A, Unlu CG, Uśpieński T, Niewiadomski P, Bartosik D, Trzaskowski B, Ocakoglu K, Kargul J. Enhancement of direct electron transfer in graphene bioelectrodes containing novel cytochrome c 553 variants with optimized heme orientation. Bioelectrochemistry 2021; 140:107818. [PMID: 33905959 DOI: 10.1016/j.bioelechem.2021.107818] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/03/2021] [Accepted: 04/03/2021] [Indexed: 11/20/2022]
Abstract
The highly efficient bioelectrodes based on single layer graphene (SLG) functionalized with pyrene self-assembled monolayer and novel cytochromec553(cytc553)peptide linker variants were rationally designed to optimize the direct electron transfer (DET) between SLG and the heme group of cyt. Through a combination of photoelectrochemical and quantum mechanical (QM/MM) approaches we show that the specific amino acid sequence of a short peptide genetically inserted between the cytc553holoprotein and thesurface anchoring C-terminal His6-tag plays a crucial role in ensuring the optimal orientation and distance of the heme group with respect to the SLG surface. Consequently, efficient DET occurring between graphene and cyt c553 leads to a 20-fold enhancement of the cathodic photocurrent output compared to the previously reported devices of a similar type. The QM/MM modeling implies that a perpendicular or parallel orientation of the heme group with respect to the SLG surface is detrimental to DET, whereas the tilted orientation favors the cathodic photocurrent generation. Our work confirms the possibility of fine-tuning the electronic communication within complex bio-organic nanoarchitectures and interfaces due to optimization of the tilt angle of the heme group, its distance from the SLG surface and optimal HOMO/LUMO levels of the interacting redox centers.
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Affiliation(s)
- Miriam Izzo
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Silvio Osella
- Chemical and Biological Systems Simulation Lab, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland.
| | - Margot Jacquet
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Małgorzata Kiliszek
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Ersan Harputlu
- Department of Engineering Fundamental Sciences, Faculty of Engineering, Tarsus University, 33400 Tarsus, Turkey
| | - Alicja Starkowska
- Chemical and Biological Systems Simulation Lab, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Anna Łasica
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - C Gokhan Unlu
- Department of Biomedical Engineering, Pamukkale University, TR-20070 Denizli, Turkey
| | - Tomasz Uśpieński
- Laboratory of Molecular and Cellular Signaling, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Paweł Niewiadomski
- Laboratory of Molecular and Cellular Signaling, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Dariusz Bartosik
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Bartosz Trzaskowski
- Chemical and Biological Systems Simulation Lab, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Kasim Ocakoglu
- Department of Engineering Fundamental Sciences, Faculty of Engineering, Tarsus University, 33400 Tarsus, Turkey
| | - Joanna Kargul
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland.
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3
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Ghosh SK, Ghosh S, Paul G, Banerjee R. A graph theoretic model to understand the behavioral difference of PPCA among its paralogs towards recognition of DXCA. J Biosci 2021; 46:35. [PMID: 33952726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Among all the proteins of Periplasmic C type Cytochrome family obtained from cytochrome C7 found in Geobacter sulfurreducens, only the Periplasmic C type Cytochrome A (PPCA) protein can recognize the deoxycholate (DXCA), while its other paralogs do not, as observed from the crystal structures. Though some existing works have used graph-theoretic approaches to realize the 3-D structural properties of proteins, its usage in the rationalisation of the physiochemical behavior of proteins has been very limited. To understand the driving force towards the recognition of DXCA exclusively by PPCA among its paralogs, in this work, we propose two graph theoretic models based on the combinatorial properties, namely, base-pair-type and impact, of the nucleotide bases and the amino acid residues, respectively. Combinatorial analysis of the binding sequences using the proposed base-pair type based graph theoretic model reveals the differential behaviour of PPCA among its other paralogs. Further, to investigate the underlying chemical phenomenon, another graph theoretic model has been developed based on impact. Analysis of the results obtained from impact-based model clearly indicates towards the helix formation of PPCA which is essential for the recognition of DXCA, making PPCA a completely different entity from its paralogs.
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Affiliation(s)
- Shankar K Ghosh
- Advanced Computing and Microelectronics Unit, Indian Statistical Institute, Kolkata 700 108, India
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4
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Zuccarello L, Berthomieu C, Boussac A, Brubach JB, Díaz-Moreno I, Díaz Quintana AJ, Hienerwadel R. Protonation of the Cysteine Axial Ligand Investigated in His/Cys c-Type Cytochrome by UV-Vis and Mid- and Far-IR Spectroscopy. J Phys Chem Lett 2020; 11:4198-4205. [PMID: 32364390 DOI: 10.1021/acs.jpclett.0c01016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
His/Cys coordination was recently found in several c-type cytochromes, which could act as sensors, in electron transport or in regulation. Toward a better understanding of Cys function and reactivity in these cytochromes, we compare cytochrome c6 (c6wt) from the cyanobacterium Nostoc PCC 7120 with its Met58Cys mutant. We probe the axial ligands and heme properties by combining visible and mid- to far-FTIR difference spectroscopies. Cys58 determines the strong negative redox potential and pH dependence of M58C (EmM58C = -375 mV, versus Emc6wt = +339 mV). Mid-IR (notably Cys ν(SH), His ν(C5N1), heme δ(CmH)) and far-IR (ν(Fe(II)-His), ν(His-Fe(III)-Cys)) markers of the heme and ligands show that Cys58 remains a strong thiolate ligand of reduced Met58Cys at alkaline pH, while it is protonated at pH 7.5, is stabilized by a strong hydrogen bonding interaction, and weakly interacts with Fe(II). These data provide a benchmark for further analysis of c-type cytochromes with natural His/Cys coordination.
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Affiliation(s)
- Lidia Zuccarello
- CEA, CNRS, Aix Marseille Univ., BIAM, Interactions Protéine Métal UMR 7265, 13108 Saint Paul-Lez-Durance, France
- Aix Marseille Univ., CEA, CNRS, BIAM, Luminy Genetics and Biophysic of Plants, UMR 7265, 13288 Marseille Cedex, France
| | - Catherine Berthomieu
- CEA, CNRS, Aix Marseille Univ., BIAM, Interactions Protéine Métal UMR 7265, 13108 Saint Paul-Lez-Durance, France
| | - Alain Boussac
- I2BC, UMR CNRS 9198, CEA Saclay, 91191 Gif-sur-Yvette, France
| | - Jean-Blaise Brubach
- Synchrotron SOLEIL, AILES Beamline, L'Orme des Merisier, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | - Irene Díaz-Moreno
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla - Consejo Superior de Investigaciones Científicas (CSIC), Avda. Américo Vespucio 49, Sevilla 41092, Spain
| | - Antonio J Díaz Quintana
- Instituto de Investigaciones Químicas (IIQ), Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla - Consejo Superior de Investigaciones Científicas (CSIC), Avda. Américo Vespucio 49, Sevilla 41092, Spain
| | - Rainer Hienerwadel
- Aix Marseille Univ., CEA, CNRS, BIAM, Luminy Genetics and Biophysic of Plants, UMR 7265, 13288 Marseille Cedex, France
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5
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Featherston ER, Rose HR, McBride MJ, Taylor EM, Boal AK, Cotruvo JA. Biochemical and Structural Characterization of XoxG and XoxJ and Their Roles in Lanthanide-Dependent Methanol Dehydrogenase Activity. Chembiochem 2019; 20:2360-2372. [PMID: 31017712 PMCID: PMC6814260 DOI: 10.1002/cbic.201900184] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Indexed: 12/31/2022]
Abstract
Lanthanide (Ln)-dependent methanol dehydrogenases (MDHs) have recently been shown to be widespread in methylotrophic bacteria. Along with the core MDH protein, XoxF, these systems contain two other proteins, XoxG (a c-type cytochrome) and XoxJ (a periplasmic binding protein of unknown function), about which little is known. In this work, we have biochemically and structurally characterized these proteins from the methyltroph Methylobacterium extorquens AM1. In contrast to results obtained in an artificial assay system, assays of XoxFs metallated with LaIII , CeIII , and NdIII using their physiological electron acceptor, XoxG, display Ln-independent activities, but the Km for XoxG markedly increases from La to Nd. This result suggests that XoxG's redox properties are tuned specifically for lighter Lns in XoxF, an interpretation supported by the unusually low reduction potential of XoxG (+172 mV). The X-ray crystal structure of XoxG provides a structural basis for this reduction potential and insight into the XoxG-XoxF interaction. Finally, the X-ray crystal structure of XoxJ reveals a large hydrophobic cleft and suggests a role in the activation of XoxF. These studies enrich our understanding of the underlying chemical principles that enable the activity of XoxF with multiple lanthanides in vitro and in vivo.
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Affiliation(s)
- Emily R. Featherston
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Hannah R. Rose
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Molly J. McBride
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Elle M. Taylor
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Amie K. Boal
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Joseph A. Cotruvo
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
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6
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Tollefson EJ, Allen CR, Chong G, Zhang X, Rozanov ND, Bautista A, Cerda JJ, Pedersen JA, Murphy CJ, Carlson EE, Hernandez R. Preferential Binding of Cytochrome c to Anionic Ligand-Coated Gold Nanoparticles: A Complementary Computational and Experimental Approach. ACS Nano 2019; 13:6856-6866. [PMID: 31082259 DOI: 10.1021/acsnano.9b01622] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Membrane-bound proteins can play a role in the binding of anionic gold nanoparticles (AuNPs) to model bilayers; however, the mechanism for this binding remains unresolved. In this work, we determine the relative orientation of the peripheral membrane protein cytochrome c in binding to a mercaptopropionic acid-functionalized AuNP (MPA-AuNP). As this is nonrigid binding, traditional methods involving crystallographic or rigid molecular docking techniques are ineffective at resolving the question. Instead, we have implemented a computational assay technique using a cross-correlation of a small ensemble of 200 ns long molecular dynamics trajectories to identify a preferred nonrigid binding orientation or pose of cytochrome c on MPA-AuNPs. We have also employed a mass spectrometry-based footprinting method that enables the characterization of the stable protein corona that forms at long time-scales in solution but remains in a dynamic state. Through the combination of these computational and experimental primary results, we have established a consensus result establishing the identity of the exposed regions of cytochrome c in proximity to MPA-AuNPs and its complementary pose(s) with amino-acid specificity. Moreover, the tandem use of the two methods can be applied broadly to determine the accessibility of membrane-binding sites for peripheral membrane proteins upon adsorption to AuNPs or to determine the exposed amino-acid residues of the hard corona that drive the acquisition of dynamic soft coronas. We anticipate that the combined use of simulation and experimental methods to characterize biomolecule-nanoparticle interactions, as demonstrated here, will become increasingly necessary as the complexity of such target systems grows.
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Affiliation(s)
- Emily J Tollefson
- Department of Chemistry , University of Minnesota-Twin Cities , Minneapolis , Minnesota 55455 , United States
| | - Caley R Allen
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Gene Chong
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Xi Zhang
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Nikita D Rozanov
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Anthony Bautista
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Jennifer J Cerda
- Department of Chemistry , University of Minnesota-Twin Cities , Minneapolis , Minnesota 55455 , United States
| | - Joel A Pedersen
- Environmental Chemistry and Technology Program , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Catherine J Murphy
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Erin E Carlson
- Department of Chemistry , University of Minnesota-Twin Cities , Minneapolis , Minnesota 55455 , United States
| | - Rigoberto Hernandez
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
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7
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Tokunou Y, Okamoto A. Geometrical Changes in the Hemes of Bacterial Surface c-Type Cytochromes Reveal Flexibility in Their Binding Affinity with Minerals. Langmuir 2019; 35:7529-7537. [PMID: 30351954 DOI: 10.1021/acs.langmuir.8b02977] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Microbial extracellular electron transport occurs via the physical and electrical association of outer-membrane c-type cytochromes (OM c-Cyts) with extracellular solid surfaces. However, studies investigating the characteristics of cytochrome binding with solid materials have been limited to the use of purified units of OM c-Cyts dissolved in solution, rather than OM c-Cyts in intact cells, because of the lack of a methodology that specifically allows for the monitoring of OM c-Cyts in whole-cells. Here, we utilized circular dichroism (CD) spectroscopy to examine the molecular mechanisms and binding characteristics of the interaction between MtrC, a unit of OM c-Cyts, in whole Shewanella oneidensis MR-1 cells and hematite nanoparticles. The addition of hematite nanoparticles significantly decreased the intensity of the Soret CD peaks, indicating geometrical changes in the hemes in MtrC associated with their physical contact with hematite. The binding affinity of MtrC estimated using CD spectra changed predominantly depending upon the redox state of MtrC and the concentration of the hematite nanoparticles. In contrast, purified MtrC demonstrated a constant binding affinity following a Langmuir isotherm, with a standard Gibbs free energy of -43 kJ mol-1, suggesting that the flexibility in the binding affinity of MtrC with hematite was specific in membrane-bound protein complex conditions. Overall, these findings suggest that the binding affinity as well as the heme geometry of OM c-Cyts are flexibly modulated in the membrane complex associated with microbe-mineral interactions.
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Affiliation(s)
- Yoshihide Tokunou
- Department of Applied Chemistry , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8656 , Japan
- International Center for Materials Nanoarchitectonics , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
| | - Akihiro Okamoto
- International Center for Materials Nanoarchitectonics , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
- Center for Functional Sensor & Actuator , National Institute for Materials Science , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
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8
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Chen JH, Yu LJ, Boussac A, Wang-Otomo ZY, Kuang T, Shen JR. Properties and structure of a low-potential, penta-heme cytochrome c 552 from a thermophilic purple sulfur photosynthetic bacterium Thermochromatium tepidum. Photosynth Res 2019; 139:281-293. [PMID: 29691716 DOI: 10.1007/s11120-018-0507-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 03/30/2018] [Indexed: 06/08/2023]
Abstract
The thermophilic purple sulfur bacterium Thermochromatium tepidum possesses four main water-soluble redox proteins involved in the electron transfer behavior. Crystal structures have been reported for three of them: a high potential iron-sulfur protein, cytochrome c', and one of two low-potential cytochrome c552 (which is a flavocytochrome c) have been determined. In this study, we purified another low-potential cytochrome c552 (LPC), determined its N-terminal amino acid sequence and the whole gene sequence, characterized it with absorption and electron paramagnetic spectroscopy, and solved its high-resolution crystal structure. This novel cytochrome was found to contain five c-type hemes. The overall fold of LPC consists of two distinct domains, one is the five heme-containing domain and the other one is an Ig-like domain. This provides a representative example for the structures of multiheme cytochromes containing an odd number of hemes, although the structures of multiheme cytochromes with an even number of hemes are frequently seen in the PDB database. Comparison of the sequence and structure of LPC with other proteins in the databases revealed several characteristic features which may be important for its functioning. Based on the results obtained, we discuss the possible intracellular function of this LPC in Tch. tepidum.
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Affiliation(s)
- Jing-Hua Chen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
- University of Chinese Academy of Sciences, Yuquan Rd, Shijingshan District, Beijing, 100049, China
| | - Long-Jiang Yu
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Alain Boussac
- I2BC, SB2SM, CNRS UMR 9198, CEA Saclay, 91191, Gif-sur-Yvette, France
| | | | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China.
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
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9
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Bernal-Bayard P, Puerto-Galán L, Yruela I, García-Rubio I, Castell C, Ortega JM, Alonso PJ, Roncel M, Martínez JI, Hervás M, Navarro JA. The photosynthetic cytochrome c 550 from the diatom Phaeodactylum tricornutum. Photosynth Res 2017; 133:273-287. [PMID: 28032235 DOI: 10.1007/s11120-016-0327-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 12/14/2016] [Indexed: 06/06/2023]
Abstract
The photosynthetic cytochrome c 550 from the marine diatom Phaeodactylum tricornutum has been purified and characterized. Cytochrome c 550 is mostly obtained from the soluble cell extract in relatively large amounts. In addition, the protein appeared to be truncated in the last hydrophobic residues of the C-terminus, both in the soluble cytochrome c 550 and in the protein extracted from the membrane fraction, as deduced by mass spectrometry analysis and the comparison with the gene sequence. Interestingly, it has been described that the C-terminus of cytochrome c 550 forms a hydrophobic finger involved in the interaction with photosystem II in cyanobacteria. Cytochrome c 550 was almost absent in solubilized photosystem II complex samples, in contrast with the PsbO and Psb31 extrinsic subunits, thus suggesting a lower affinity of cytochrome c 550 for the photosystem II complex. Under iron-limiting conditions the amount of cytochrome c 550 decreases up to about 45% as compared to iron-replete cells, pointing to an iron-regulated synthesis. Oxidized cytochrome c 550 has been characterized using continuous wave EPR and pulse techniques, including HYSCORE, and the obtained results have been interpreted in terms of the electrostatic charge distribution in the surroundings of the heme centre.
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Affiliation(s)
- Pilar Bernal-Bayard
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - Leonor Puerto-Galán
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | | | - Inés García-Rubio
- Centro Universitario de la Defensa, Zaragoza, Spain
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
| | - Carmen Castell
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - José M Ortega
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - Pablo J Alonso
- Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza & CSIC, Zaragoza, Spain
| | - Mercedes Roncel
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - Jesús I Martínez
- Centro Universitario de la Defensa, Zaragoza, Spain
- Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza & CSIC, Zaragoza, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain.
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10
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Silveira CM, Quintas PO, Moura I, Moura JJG, Hildebrandt P, Almeida MG, Todorovic S. SERR Spectroelectrochemical Study of Cytochrome cd1 Nitrite Reductase Co-Immobilized with Physiological Redox Partner Cytochrome c552 on Biocompatible Metal Electrodes. PLoS One 2015; 10:e0129940. [PMID: 26091174 PMCID: PMC4474632 DOI: 10.1371/journal.pone.0129940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 05/14/2015] [Indexed: 01/13/2023] Open
Abstract
Cytochrome cd1 nitrite reductases (cd1NiRs) catalyze the one-electron reduction of nitrite to nitric oxide. Due to their catalytic reaction, cd1NiRs are regarded as promising components for biosensing, bioremediation and biotechnological applications. Motivated by earlier findings that catalytic activity of cd1NiR from Marinobacter hydrocarbonoclasticus (Mhcd1) depends on the presence of its physiological redox partner, cytochrome c552 (cyt c552), we show here a detailed surface enhanced resonance Raman characterization of Mhcd1 and cyt c552 attached to biocompatible electrodes in conditions which allow direct electron transfer between the conducting support and immobilized proteins. Mhcd1 and cyt c552 are co-immobilized on silver electrodes coated with self-assembled monolayers (SAMs) and the electrocatalytic activity of Ag // SAM // Mhcd1 // cyt c552 and Ag // SAM // cyt c552 // Mhcd1 constructs is tested in the presence of nitrite. Simultaneous evaluation of structural and thermodynamic properties of the immobilized proteins reveals that cyt c552 retains its native properties, while the redox potential of apparently intact Mhcd1 undergoes a ~150 mV negative shift upon adsorption. Neither of the immobilization strategies results in an active Mhcd1, reinforcing the idea that subtle and very specific interactions between Mhcd1 and cyt c552 govern efficient intermolecular electron transfer and catalytic activity of Mhcd1.
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Affiliation(s)
- Célia M. Silveira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- * E-mail: (CMS); (ST)
| | - Pedro O. Quintas
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Isabel Moura
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - José J. G. Moura
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | | | - M. Gabriela Almeida
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Superior de Ciências da Saúde Egas Moniz, Caparica, Portugal
| | - Smilja Todorovic
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- * E-mail: (CMS); (ST)
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12
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Tozawa K, Ferguson SJ, Redfield C, Smith LJ. Comparison of the backbone dynamics of wild-type Hydrogenobacter thermophilus cytochrome c(552) and its b-type variant. J Biomol NMR 2015; 62:221-231. [PMID: 25953310 PMCID: PMC4451467 DOI: 10.1007/s10858-015-9938-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/27/2015] [Indexed: 06/04/2023]
Abstract
Cytochrome c552 from the thermophilic bacterium Hydrogenobacter thermophilus is a typical c-type cytochrome which binds heme covalently via two thioether bonds between the two heme vinyl groups and two cysteine thiol groups in a CXXCH sequence motif. This protein was converted to a b-type cytochrome by substitution of the two cysteine residues by alanines (Tomlinson and Ferguson in Proc Natl Acad Sci USA 97:5156-5160, 2000a). To probe the significance of the covalent attachment of the heme in the c-type protein, (15)N relaxation and hydrogen exchange studies have been performed for the wild-type and b-type proteins. The two variants share very similar backbone dynamic properties, both proteins showing high (15)N order parameters in the four main helices, with reduced values in an exposed loop region (residues 18-21), and at the C-terminal residue Lys80. Some subtle changes in chemical shift and hydrogen exchange protection are seen between the wild-type and b-type variant proteins, not only for residues at and neighbouring the mutation sites, but also for some residues in the heme binding pocket. Overall, the results suggest that the main role of the covalent linkages between the heme group and the protein chain must be to increase the stability of the protein.
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Affiliation(s)
- Kaeko Tozawa
- />Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Stuart J. Ferguson
- />Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Christina Redfield
- />Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Lorna J. Smith
- />Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR UK
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Nagao S, Ueda M, Osuka H, Komori H, Kamikubo H, Kataoka M, Higuchi Y, Hirota S. Domain-swapped dimer of Pseudomonas aeruginosa cytochrome c551: structural insights into domain swapping of cytochrome c family proteins. PLoS One 2015; 10:e0123653. [PMID: 25853415 PMCID: PMC4390240 DOI: 10.1371/journal.pone.0123653] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 02/23/2015] [Indexed: 02/06/2023] Open
Abstract
Cytochrome c (cyt c) family proteins, such as horse cyt c, Pseudomonas aeruginosa cytochrome c551 (PA cyt c551), and Hydrogenobacter thermophilus cytochrome c552 (HT cyt c552), have been used as model proteins to study the relationship between the protein structure and folding process. We have shown in the past that horse cyt c forms oligomers by domain swapping its C-terminal helix, perturbing the Met–heme coordination significantly compared to the monomer. HT cyt c552 forms dimers by domain swapping the region containing the N-terminal α-helix and heme, where the heme axial His and Met ligands belong to different protomers. Herein, we show that PA cyt c551 also forms domain-swapped dimers by swapping the region containing the N-terminal α-helix and heme. The secondary structures of the M61A mutant of PA cyt c551 were perturbed slightly and its oligomer formation ability decreased compared to that of the wild-type protein, showing that the stability of the protein secondary structures is important for domain swapping. The hinge loop of domain swapping for cyt c family proteins corresponded to the unstable region specified by hydrogen exchange NMR measurements for the monomer, although the swapping region differed among proteins. These results show that the unstable loop region has a tendency to become a hinge loop in domain-swapped proteins.
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Affiliation(s)
- Satoshi Nagao
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916–5 Takayama, Ikoma, Nara 630–0192, Japan
| | - Mariko Ueda
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916–5 Takayama, Ikoma, Nara 630–0192, Japan
| | - Hisao Osuka
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916–5 Takayama, Ikoma, Nara 630–0192, Japan
- Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678–1297, Japan
| | - Hirofumi Komori
- Faculty of Education, Kagawa University, 1–1 Saiwai-cho, Takamatsu, Kagawa 760–8522, Japan
- RIKEN SPring-8 Center, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679–5148, Japan
| | - Hironari Kamikubo
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916–5 Takayama, Ikoma, Nara 630–0192, Japan
| | - Mikio Kataoka
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916–5 Takayama, Ikoma, Nara 630–0192, Japan
| | - Yoshiki Higuchi
- Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678–1297, Japan
- RIKEN SPring-8 Center, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679–5148, Japan
| | - Shun Hirota
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916–5 Takayama, Ikoma, Nara 630–0192, Japan
- * E-mail:
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14
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Affiliation(s)
- Y Sambongi
- Department of Agricultural Chemistry, University of Tokyo, Japan
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15
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Kashey TS, Cowgill JB, McConnell MD, Flores M, Redding KE. Expression and characterization of cytochrome c553 from Heliobacterium modesticaldum. Photosynth Res 2014; 120:291-299. [PMID: 24557489 DOI: 10.1007/s11120-014-9982-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 02/05/2014] [Indexed: 06/03/2023]
Abstract
Cytochrome c553 of Heliobacterium modesticaldum is the donor to P800 (+), the primary electron donor of the heliobacterial reaction center (HbRC). It is a membrane-anchored 14-kDa cytochrome that accomplishes electron transfer from the cytochrome bc complex to the HbRC. The petJ gene encoding cyt c 553 was cloned and expressed in Escherichia coli with a hexahistidine tag replacing the lipid attachment site to create a soluble donor that could be made in a preparative scale. The recombinant cytochrome had spectral characteristics typical of a c-type cytochrome, including an asymmetric α-band, and a slightly red-shifted Soret band when reduced. The EPR spectrum of the oxidized protein was characteristic of a low-spin cytochrome. The midpoint potential of the recombinant cytochrome was +217 ± 10 mV. The interaction between soluble recombinant cytochrome c 553 and the HbRC was also studied. Re-reduction of photooxidized P800 (+) was accelerated by addition of reduced cytochrome c 553. The kinetics were characteristic of a bimolecular reaction with a second order rate of 1.53 × 10(4) M(-1) s(-1) at room temperature. The rate manifested a steep temperature dependence, with a calculated activation energy of 91 kJ mol(-1), similar to that of the native protein in Heliobacillus gestii cells. These data demonstrate that the recombinant soluble cytochrome is comparable to the native protein, and likely lacks a discrete electrostatic binding site on the HbRC.
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Affiliation(s)
- Trevor S Kashey
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-1604, USA
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16
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Oswald VF, Chen W, Harvilla PB, Magyar JS. Overexpression, purification, and enthalpy of unfolding of ferricytochrome c552 from a psychrophilic microorganism. J Inorg Biochem 2014; 131:76-8. [PMID: 24275750 PMCID: PMC3885257 DOI: 10.1016/j.jinorgbio.2013.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 11/04/2013] [Accepted: 11/05/2013] [Indexed: 11/28/2022]
Abstract
The psychrophilic, hydrocarbonoclastic microorganism Colwellia psychrerythraea is important in global nutrient cycling and bioremediation. In order to investigate how this organism can live so efficiently at low temperatures (~4°C), thermal denaturation studies of a small electron transfer protein from Colwellia were performed. Colwellia cytochrome c552 was overexpressed in Escherichia coli, isolated, purified, and characterized by UV-visible absorption spectroscopy. The melting temperature (Tm) and the van't Hoff enthalpy (ΔHvH) were determined. These values suggest an unexpectedly high stability for this psychrophilic cytochrome.
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Affiliation(s)
- Victoria F Oswald
- Department of Chemistry, Barnard College, Columbia University, New York, NY 10027, United States
| | - WeiTing Chen
- Department of Chemistry, Barnard College, Columbia University, New York, NY 10027, United States
| | - Paul B Harvilla
- Department of Chemistry, Barnard College, Columbia University, New York, NY 10027, United States; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, United States
| | - John S Magyar
- Department of Chemistry, Barnard College, Columbia University, New York, NY 10027, United States.
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17
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Yu LJ, Unno M, Kimura Y, Yanagimoto K, Oh-oka H, Wang-Otomo ZY. Structure analysis and characterization of the cytochrome c-554 from thermophilic green sulfur photosynthetic bacterium Chlorobaculum tepidum. Photosynth Res 2013; 118:249-258. [PMID: 24052268 DOI: 10.1007/s11120-013-9922-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/03/2013] [Indexed: 06/02/2023]
Abstract
The cytochrome (Cyt) c-554 in thermophilic green photosynthetic bacterium Chlorobaculum tepidum serves as an intermediate electron carrier, transferring electrons to the membrane-bound Cyt c z from various enzymes involved in the oxidations of sulfide, thiosulfate, and sulfite compounds. Spectroscopically, this protein exhibits an asymmetric α-absorption band for the reduced form and particularly large paramagnetic (1)H NMR shifts for the heme methyl groups with an unusual shift pattern in the oxidized form. The crystal structure of the Cyt c-554 has been determined at high resolution. The overall fold consists of four α-helices and is characterized by a remarkably long and flexible loop between the α3 and α4 helices. The axial ligand methionine has S-chirality at the sulfur atom with its C(ε)H3 group pointing toward the heme pyrrole ring I. This configuration corresponds to an orientation of the lone-pair orbital of the sulfur atom directed at the pyrrole ring II and explains the lowest-field (1)H NMR shift arising from the 18(1) heme methyl protons. Differing from most other class I Cyts c, no hydrogen bond was formed between the methionine sulfur atom and polypeptide chain. Lack of this hydrogen bond may account for the observed large paramagnetic (1)H NMR shifts of the heme methyl protons. The surface-exposed heme pyrrole ring II edge is in a relatively hydrophobic environment surrounded by several electronically neutral residues. This portion is considered as an electron transfer gateway. The structure of the Cyt c-554 is compared with those of other Cyts c, and possible interactions of this protein with its electron transport partners are discussed.
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Affiliation(s)
- Long-Jiang Yu
- Faculty of Science, Ibaraki University, Bunkyo 2-1-1, Mito, 310-8512, Japan
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18
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Masone D, Aloia FC, Del Pópolo MG. H-bond refinement for electron transfer membrane-bound protein-protein complexes: cytochrome c oxidase and cytochrome c552. Comput Biol Chem 2013; 47:31-6. [PMID: 23872047 DOI: 10.1016/j.compbiolchem.2013.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/29/2013] [Accepted: 05/30/2013] [Indexed: 11/19/2022]
Abstract
In this study we propose a protocol to evaluate membrane-bound cytochrome c oxidase-cytochrome c552 docking candidates. An initial rigid docking algorithm generates docking poses of the cytochrome c oxidase-cytochrome c552, candidates are then aggregated into a 512-DPPC membrane model and solvated in explicit solvent. Molecular dynamic simulations are performed to induce conformational changes to membrane-bound protein complexes. Lastly each protein-protein complex is optimized in terms of its hydrogen bond network, evaluated energetically and ranked. The protocol is directly applicable to other membrane-protein complexes, such as protein-ligand systems.
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Affiliation(s)
- Diego Masone
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Ciencias Básicas (ICB), Universidad Nacional de Cuyo (UNCUYO), Argentina.
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19
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Forman CJ, Wang N, Yang ZY, Mowat CG, Jarvis S, Durkan C, Barker PD. Probing the location of displayed cytochrome b562 on amyloid by scanning tunnelling microscopy. Nanotechnology 2013; 24:175102. [PMID: 23571459 DOI: 10.1088/0957-4484/24/17/175102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Amyloid fibres displaying cytochrome b562 were probed using scanning tunnelling microscopy (STM) in vacuo. The cytochromes are electron transfer proteins containing a haem cofactor and could, in principle, mediate electron transfer between the tip and the gold substrate. If the core fibres were insulating and electron transfer within the 3D haem network was detected, then the electron transport properties of the fibre could be controlled by genetic engineering. Three kinds of STM images were obtained. At a low bias (<1.5 V) the fibres appeared as regions of low conductivity with no evidence of cytochrome mediated electron transfer. At a high bias, stable peaks in tunnelling current were observed for all three fibre species containing haem and one species of fibre that did not contain haem. In images of this kind, some of the current peaks were collinear and spaced around 10 nm apart over ranges longer than 100 nm, but background monomers complicate interpretation. Images of the third kind were rare (1 in 150 fibres); in these, fully conducting structures with the approximate dimensions of fibres were observed, suggesting the possibility of an intermittent conduction mechanism, for which a precedent exists in DNA. To test the conductivity, some fibres were immobilized with sputtered gold, and no evidence of conduction between the grains of gold was seen. In control experiments, a variation of monomeric cytochrome b562 was not detected by STM, which was attributed to low adhesion, whereas a monomeric multi-haem protein, GSU1996, was readily imaged. We conclude that the fibre superstructure may be intermittently conducting, that the cytochromes have been seen within the fibres and that they are too far apart for detectable current flow between sites to occur. We predict that GSU1996, being 10 nm long, is more likely to mediate successful electron transfer along the fibre as well as being more readily detectable when displayed from amyloid.
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Affiliation(s)
- C J Forman
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK.
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Robin S, Arese M, Forte E, Sarti P, Kolaj-Robin O, Giuffrè A, Soulimane T. Functional dissection of the multi-domain di-heme cytochrome c(550) from Thermus thermophilus. PLoS One 2013; 8:e55129. [PMID: 23383080 PMCID: PMC3561395 DOI: 10.1371/journal.pone.0055129] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 12/18/2012] [Indexed: 11/18/2022] Open
Abstract
In bacteria, oxidation of sulfite to sulfate, the most common strategy for sulfite detoxification, is mainly accomplished by the molybdenum-containing sulfite:acceptor oxidoreductases (SORs). Bacterial SORs are very diverse proteins; they can exist as monomers or homodimers of their core subunit, as well as heterodimers with an additional cytochrome c subunit. We have previously described the homodimeric SOR from Thermus thermophilus HB8 (SOR(TTHB8)), identified its physiological electron acceptor, cytochrome c(550), and demonstrated the key role of the latter in coupling sulfite oxidation to aerobic respiration. Herein, the role of this di-heme cytochrome c was further investigated. The cytochrome was shown to be composed of two conformationally independent domains, each containing one heme moiety. Each domain was separately cloned, expressed in E. coli and purified to homogeneity. Stopped-flow experiments showed that: i) the N-terminal domain is the only one accepting electrons from SOR(TTHB8); ii) the N- and C-terminal domains are in rapid redox equilibrium and iii) both domains are able to transfer electrons further to cytochrome c(552), the physiological substrate of the ba(3) and caa(3) terminal oxidases. These findings show that cytochrome c(550) functions as a electron shuttle, without working as an electron wire with one heme acting as the electron entry and the other as the electron exit site. Although contribution of the cytochrome c(550) C-terminal domain to T. thermophilus sulfur respiration seems to be dispensable, we suggest that di-heme composition of the cytochrome physiologically enables storage of the two electrons generated from sulfite oxidation, thereof ensuring efficient contribution of sulfite detoxification to the respiratory chain-mediated energy generation.
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Affiliation(s)
- Sylvain Robin
- Chemical and Environmental Science Department, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
| | - Marzia Arese
- Department of Biochemical Sciences and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Elena Forte
- Department of Biochemical Sciences and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Paolo Sarti
- Department of Biochemical Sciences and Istituto Pasteur – Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
- Consiglio Nazionale delle Ricerche Istituto di Biologia e Patologia Molecolari, Rome, Italy
| | - Olga Kolaj-Robin
- Chemical and Environmental Science Department, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
| | - Alessandro Giuffrè
- Consiglio Nazionale delle Ricerche Istituto di Biologia e Patologia Molecolari, Rome, Italy
- * E-mail: (AG); (TS)
| | - Tewfik Soulimane
- Chemical and Environmental Science Department, Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
- * E-mail: (AG); (TS)
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Ji J, Nie L, Qiao L, Li Y, Guo L, Liu B, Yang P, Girault HH. Proteolysis in microfluidic droplets: an approach to interface protein separation and peptide mass spectrometry. Lab Chip 2012; 12:2625-9. [PMID: 22695710 DOI: 10.1039/c2lc40206h] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A versatile microreactor protocol based on microfluidic droplets has been developed for on-line protein digestion. Proteins separated by liquid chromatography are fractionated in water-in-oil droplets and digested in sequence. The microfluidic reactor acts also as an electrospray ionization emitter for mass spectrometry analysis of the peptides produced in the individual droplets. Each droplet is an enzymatic micro-reaction unit with efficient proteolysis due to rapid mixing, enhanced mass transfer and automated handling. This droplet approach eliminates sample loss, cross-contamination, non-specific absorption and memory effect. A protein mixture was successfully identified using the droplet-based micro-reactor as interface between reverse phase liquid chromatography and mass spectrometry.
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Affiliation(s)
- Ji Ji
- Department of Chemistry, Institute of Biomedical Sciences and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, China
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22
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Marritt SJ, Lowe TG, Bye J, McMillan DGG, Shi L, Fredrickson J, Zachara J, Richardson DJ, Cheesman MR, Jeuken LJC, Butt JN. A functional description of CymA, an electron-transfer hub supporting anaerobic respiratory flexibility in Shewanella. Biochem J 2012; 444:465-74. [PMID: 22458729 DOI: 10.1042/bj20120197] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
CymA (tetrahaem cytochrome c) is a member of the NapC/NirT family of quinol dehydrogenases. Essential for the anaerobic respiratory flexibility of shewanellae, CymA transfers electrons from menaquinol to various dedicated systems for the reduction of terminal electron acceptors including fumarate and insoluble minerals of Fe(III). Spectroscopic characterization of CymA from Shewanella oneidensis strain MR-1 identifies three low-spin His/His co-ordinated c-haems and a single high-spin c-haem with His/H(2)O co-ordination lying adjacent to the quinol-binding site. At pH 7, binding of the menaquinol analogue, 2-heptyl-4-hydroxyquinoline-N-oxide, does not alter the mid-point potentials of the high-spin (approximately -240 mV) and low-spin (approximately -110, -190 and -265 mV) haems that appear biased to transfer electrons from the high- to low-spin centres following quinol oxidation. CymA is reduced with menadiol (E(m) = -80 mV) in the presence of NADH (E(m) = -320 mV) and an NADH-menadione (2-methyl-1,4-naphthoquinone) oxidoreductase, but not by menadiol alone. In cytoplasmic membranes reduction of CymA may then require the thermodynamic driving force from NADH, formate or H2 oxidation as the redox poise of the menaquinol pool in isolation is insufficient. Spectroscopic studies suggest that CymA requires a non-haem co-factor for quinol oxidation and that the reduced enzyme forms a 1:1 complex with its redox partner Fcc3 (flavocytochrome c3 fumarate reductase). The implications for CymA supporting the respiratory flexibility of shewanellae are discussed.
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Affiliation(s)
- Sophie J Marritt
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, U.K
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23
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Firer-Sherwood MA, Ando N, Drennan CL, Elliott SJ. Solution-based structural analysis of the decaheme cytochrome, MtrA, by small-angle X-ray scattering and analytical ultracentrifugation. J Phys Chem B 2011; 115:11208-14. [PMID: 21838277 PMCID: PMC3178274 DOI: 10.1021/jp203603r] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 08/12/2011] [Indexed: 01/05/2023]
Abstract
The potential exploitation of metal-reducing bacteria as a means for environmental cleanup or alternative fuel is an exciting prospect; however, the cellular processes that would allow for these applications need to be better understood. MtrA is a periplasmic decaheme c-type cytochrome from Shewanella oneidensis involved in the reduction of extracellular iron oxides and therefore is a critical element in Shewanella ability to engage in extracellular charge transfer. As a relatively small 333-residue protein, the heme content is surprisingly high. MtrA is believed to obtain electrons from the inner membrane-bound quinol oxidoreductase, CymA, and shuttle them across the outer membrane to MtrC, another decaheme cytochrome that directly interacts with insoluble metal oxides. How MtrA is able to perform this task is a question of interest. Here through the use of two solution-based techniques, small-angle X-ray scattering (SAXS) and analytical ultracentrifugation (AUC), we present the first structural analysis of MtrA. Our results establish that between 0.5 and 4 mg/mL, MtrA exists as a monomeric protein that is shaped like an extended molecular "wire" with a maximum protein dimension (D(max)) of 104 Å and a rod-like aspect ratio of 2.2 to 2.5. This study contributes to a greater understanding of how MtrA fulfills its role in the redox processes that must occur before electrons reach the outside of the cell.
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Affiliation(s)
- Mackenzie A. Firer-Sherwood
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Nozomi Ando
- Howard Hughes Medical Institute, Departments of Biology and Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Catherine L. Drennan
- Howard Hughes Medical Institute, Departments of Biology and Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Sean J. Elliott
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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24
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Castellani M, Havens J, Kleinschroth T, Millett F, Durham B, Malatesta F, Ludwig B. The acidic domain of cytochrome c₁ in paracoccus denitrificans, analogous to the acidic subunits in eukaryotic bc₁ complexes, is not involved in the electron transfer reaction to its native substrate cytochrome c(552). Biochim Biophys Acta 2011; 1807:1383-9. [PMID: 21856278 DOI: 10.1016/j.bbabio.2011.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/03/2011] [Accepted: 08/05/2011] [Indexed: 11/19/2022]
Abstract
The cytochrome bc(1) complex is a key component in several respiratory pathways. One of the characteristics of the eukaryotic complex is the presence of a small acidic subunit, which is thought to guide the interaction of the complex with its electron acceptor and facilitate electron transfer. Paracoccus denitrificans represents the only example of a prokaryotic organism in which a highly acidic domain is covalently fused to the cytochrome c(1) subunit. In this work, a deletion variant lacking this acidic domain has been produced and purified by affinity chromatography. The complex is fully intact as shown by its X-ray structure, and is a dimer (Kleinschroth et al., subm.) compared to the tetrameric (dimer-of-dimer) state of the wild-type. The variant complex is studied by steady-state kinetics and flash photolysis, showing wild type turnover and a virtually identical interaction with its substrate cytochrome c(552).
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Affiliation(s)
- Michela Castellani
- Institute of Biochemistry, Molecular Genetics, Goethe University, D-60438 Frankfurt am Main and Cluster of Excellence "Macromolecular Complexes" (CEF-MC), D-60438 Frankfurt am Main, Germany
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25
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Harbitz E, Andersson KK. Cytochrome c-554 from Methylosinus trichosporium OB3b; a protein that belongs to the cytochrome c2 family and exhibits a HALS-Type EPR signal. PLoS One 2011; 6:e22014. [PMID: 21789203 PMCID: PMC3138771 DOI: 10.1371/journal.pone.0022014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 06/10/2011] [Indexed: 11/19/2022] Open
Abstract
A small soluble cytochrome c-554 purified from Methylosinus trichosporium OB3b has been purified and analyzed by amino acid sequencing, mass spectrometry, visible, CD and EPR spectroscopies. It is found to be a mono heme protein with a characteristic cytochrome c fold, thus fitting into the class of cytochrome c2, which is the bacterial homologue of mitochondrial cytochrome c. The heme iron has a Histidine/Methionine axial ligation and exhibits a highly anisotropic/axial low spin (HALS) EPR signal, with a gmax at 3.40, and ligand field parameters V/ξ = 0.99, Δ/ξ = 4.57. This gives the rhombicity V/Δ = 0.22. The structural basis for this HALS EPR signal in Histidine/Methionine ligated hemes is not resolved. The ligand field parameters observed for cytochrome c-554 fits the observed pattern for other cytochromes with similar ligation and EPR behaviour.
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Affiliation(s)
- Espen Harbitz
- Department of Molecular Biosciences, University of Oslo, Oslo, Norway
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26
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Kilmartin JR, Maher MJ, Krusong K, Noble CJ, Hanson GR, Bernhardt PV, Riley MJ, Kappler U. Insights into structure and function of the active site of SoxAX cytochromes. J Biol Chem 2011; 286:24872-81. [PMID: 21592966 PMCID: PMC3137062 DOI: 10.1074/jbc.m110.212183] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 04/20/2011] [Indexed: 11/06/2022] Open
Abstract
SoxAX cytochromes catalyze the formation of heterodisulfide bonds between inorganic sulfur compounds and a carrier protein, SoxYZ. They contain unusual His/Cys-ligated heme groups with complex spectroscopic signatures. The heme-ligating cysteine has been implicated in SoxAX catalysis, but neither the SoxAX spectroscopic properties nor its catalysis are fully understood at present. We have solved the first crystal structure for a group 2 SoxAX protein (SnSoxAX), where an N-terminal extension of SoxX forms a novel structure that supports dimer formation. Crystal structures of SoxAX with a heme ligand substitution (C236M) uncovered an inherent flexibility of this SoxA heme site, with both bonding distances and relative ligand orientation differing between asymmetric units and the new residue, Met(236), representing an unusual rotamer of methionine. The flexibility of the SnSoxAX(C236M) SoxA heme environment is probably the cause of the four distinct, new EPR signals, including a high spin ferric heme form, that were observed for the enzyme. Despite the removal of the catalytically active cysteine heme ligand and drastic changes in the redox potential of the SoxA heme (WT, -479 mV; C236M, +85 mV), the substituted enzyme was catalytically active in glutathione-based assays although with reduced turnover numbers (WT, 3.7 s(-1); C236M, 2.0 s(-1)). SnSoxAX(C236M) was also active in assays using SoxYZ and thiosulfate as the sulfur substrate, suggesting that Cys(236) aids catalysis but is not crucial for it. The SoxYZ-based SoxAX assay is the first assay for an isolated component of the Sox multienzyme system.
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Affiliation(s)
- James R. Kilmartin
- From the Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, and
| | - Megan J. Maher
- the Structural Biology Program, Centenary Institute, Locked Bag 6, Sydney, New South Wales 2042, Australia
- the School of Molecular Bioscience, University of Sydney, New South Wales 2006, Australia, and
| | - Kuakarun Krusong
- the Department of Biochemistry, Chulalongkorn University, Bangkok 10330, Thailand
| | - Christopher J. Noble
- the Centre for Advanced Imaging, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Graeme R. Hanson
- the Centre for Advanced Imaging, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Paul V. Bernhardt
- From the Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, and
| | - Mark J. Riley
- From the Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, and
| | - Ulrike Kappler
- From the Centre for Metals in Biology, School of Chemistry and Molecular Biosciences, and
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27
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Dell'acqua S, Moura I, Moura JJG, Pauleta SR. The electron transfer complex between nitrous oxide reductase and its electron donors. J Biol Inorg Chem 2011; 16:1241-54. [PMID: 21739254 DOI: 10.1007/s00775-011-0812-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 06/20/2011] [Indexed: 11/25/2022]
Abstract
Identifying redox partners and the interaction surfaces is crucial for fully understanding electron flow in a respiratory chain. In this study, we focused on the interaction of nitrous oxide reductase (N(2)OR), which catalyzes the final step in bacterial denitrification, with its physiological electron donor, either a c-type cytochrome or a type 1 copper protein. The comparison between the interaction of N(2)OR from three different microorganisms, Pseudomonas nautica, Paracoccus denitrificans, and Achromobacter cycloclastes, with their physiological electron donors was performed through the analysis of the primary sequence alignment, electrostatic surface, and molecular docking simulations, using the bimolecular complex generation with global evaluation and ranking algorithm. The docking results were analyzed taking into account the experimental data, since the interaction is suggested to have either a hydrophobic nature, in the case of P. nautica N(2)OR, or an electrostatic nature, in the case of P. denitrificans N(2)OR and A. cycloclastes N(2)OR. A set of well-conserved residues on the N(2)OR surface were identified as being part of the electron transfer pathway from the redox partner to N(2)OR (Ala495, Asp519, Val524, His566 and Leu568 numbered according to the P. nautica N(2)OR sequence). Moreover, we built a model for Wolinella succinogenes N(2)OR, an enzyme that has an additional c-type-heme-containing domain. The structures of the N(2)OR domain and the c-type-heme-containing domain were modeled and the full-length structure was obtained by molecular docking simulation of these two domains. The orientation of the c-type-heme-containing domain relative to the N(2)OR domain is similar to that found in the other electron transfer complexes.
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Affiliation(s)
- Simone Dell'acqua
- REQUIMTE/CQFB, Departamento de Química, Universidade Nova de Lisboa, Caparica, Portugal
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28
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Abstract
The Poisson-Nernst-Planck (PNP) model is based on a mean-field approximation of ion interactions and continuum descriptions of concentration and electrostatic potential. It provides qualitative explanation and increasingly quantitative predictions of experimental measurements for the ion transport problems in many areas such as semiconductor devices, nanofluidic systems, and biological systems, despite many limitations. While the PNP model gives a good prediction of the ion transport phenomenon for chemical, physical, and biological systems, the number of equations to be solved and the number of diffusion coefficient profiles to be determined for the calculation directly depend on the number of ion species in the system, since each ion species corresponds to one Nernst-Planck equation and one position-dependent diffusion coefficient profile. In a complex system with multiple ion species, the PNP can be computationally expensive and parameter demanding, as experimental measurements of diffusion coefficient profiles are generally quite limited for most confined regions such as ion channels, nanostructures and nanopores. We propose an alternative model to reduce number of Nernst-Planck equations to be solved in complex chemical and biological systems with multiple ion species by substituting Nernst-Planck equations with Boltzmann distributions of ion concentrations. As such, we solve the coupled Poisson-Boltzmann and Nernst-Planck (PBNP) equations, instead of the PNP equations. The proposed PBNP equations are derived from a total energy functional by using the variational principle. We design a number of computational techniques, including the Dirichlet to Neumann mapping, the matched interface and boundary, and relaxation based iterative procedure, to ensure efficient solution of the proposed PBNP equations. Two protein molecules, cytochrome c551 and Gramicidin A, are employed to validate the proposed model under a wide range of bulk ion concentrations and external voltages. Extensive numerical experiments show that there is an excellent consistency between the results predicted from the present PBNP model and those obtained from the PNP model in terms of the electrostatic potentials, ion concentration profiles, and current-voltage (I-V) curves. The present PBNP model is further validated by a comparison with experimental measurements of I-V curves under various ion bulk concentrations. Numerical experiments indicate that the proposed PBNP model is more efficient than the original PNP model in terms of simulation time.
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Affiliation(s)
- Qiong Zheng
- Department of Mathematics, Michigan State University, East Lansing, Michigan 48824, USA
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29
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Chung JK, Thielges MC, Bowman SEJ, Bren KL, Fayer MD. Temperature dependent equilibrium native to unfolded protein dynamics and properties observed with IR absorption and 2D IR vibrational echo experiments. J Am Chem Soc 2011; 133:6681-91. [PMID: 21469666 PMCID: PMC3088310 DOI: 10.1021/ja111009s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dynamic and structural properties of carbonmonoxy (CO)-coordinated cytochrome c(552) from Hydrogenobacter thermophilus (Ht-M61A) at different temperatures under thermal equilibrium conditions were studied with infrared absorption spectroscopy and ultrafast two-dimensional infrared (2D IR) vibrational echo experiments using the heme-bound CO as the vibrational probe. Depending on the temperature, the stretching mode of CO shows two distinct bands corresponding to the native and unfolded proteins. As the temperature is increased from low temperature, a new absorption band for the unfolded protein grows in and the native band decreases in amplitude. Both the temperature-dependent circular dichroism and the IR absorption area ratio R(A)(T), defined as the ratio of the area under the unfolded band to the sum of the areas of the native and unfolded bands, suggest a two-state transition from the native to the unfolded protein. However, it is found that the absorption spectrum of the unfolded protein increases its inhomogeneous line width and the center frequency shifts as the temperature is increased. The changes in line width and center frequency demonstrate that the unfolding does not follow simple two-state behavior. The temperature-dependent 2D IR vibrational echo experiments show that the fast dynamics of the native protein are virtually temperature independent. In contrast, the fast dynamics of the unfolded protein are slower than those of the native protein, and the unfolded protein fast dynamics and at least a portion of the slower dynamics of the unfolded protein change significantly, becoming faster as the temperature is raised. The temperature dependence of the absorption spectrum and the changes in dynamics measured with the 2D IR experiments confirm that the unfolded ensemble of conformers continuously changes its nature as unfolding proceeds, in contrast to the native state, which displays a temperature-independent distribution of structures.
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Affiliation(s)
- Jean K. Chung
- Department of Chemistry, Stanford University, Stanford, California 94305
| | - Megan C. Thielges
- Department of Chemistry, Stanford University, Stanford, California 94305
| | - Sarah E. J. Bowman
- Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - Kara L. Bren
- Department of Chemistry, University of Rochester, Rochester, New York 14627
| | - M. D. Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305
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30
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Cort JR, Swenson MW, Magnuson TS. 1H, 13C, and 15N backbone, side-chain, and heme chemical shift assignments for oxidized and reduced forms of the monoheme c-type cytochrome ApcA isolated from the acidophilic metal-reducing bacterium Acidiphilium cryptum. Biomol NMR Assign 2011; 5:89-92. [PMID: 21197590 DOI: 10.1007/s12104-010-9274-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 10/05/2010] [Indexed: 05/30/2023]
Abstract
We report the (1)H, (13)C, and (15)N chemical shift assignments of both oxidized and reduced forms of an abundant periplasmic c-type cytochrome, designated ApcA, isolated from the acidophilic gram-negative facultatively anaerobic metal-reducing alphaproteobacterium Acidiphilium cryptum. These resonance assignments prove that ApcA is a monoheme cytochrome c (2) and the product of the Acry_2099 gene. An absence of resonance peaks in the NMR spectra for the 21N-terminal residues suggests that a predicted N-terminal signal sequence is cleaved. We also describe the preparation and purification of the protein in labeled form from laboratory cultures of A. cryptum growing on (13)C- and (15)N- labeled substrates.
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Affiliation(s)
- John R Cort
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
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31
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Lowe EC, Bydder S, Hartshorne RS, Tape HLU, Dridge EJ, Debieux CM, Paszkiewicz K, Singleton I, Lewis RJ, Santini JM, Richardson DJ, Butler CS. Quinol-cytochrome c oxidoreductase and cytochrome c4 mediate electron transfer during selenate respiration in Thauera selenatis. J Biol Chem 2010; 285:18433-42. [PMID: 20388716 PMCID: PMC2881769 DOI: 10.1074/jbc.m110.115873] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 04/01/2010] [Indexed: 11/06/2022] Open
Abstract
Selenate reductase (SER) from Thauera selenatis is a periplasmic enzyme that has been classified as a type II molybdoenzyme. The enzyme comprises three subunits SerABC, where SerC is an unusual b-heme cytochrome. In the present work the spectropotentiometric characterization of the SerC component and the identification of redox partners to SER are reported. The mid-point redox potential of the b-heme was determined by optical titration (E(m) + 234 +/- 10 mV). A profile of periplasmic c-type cytochromes expressed in T. selenatis under selenate respiring conditions was undertaken. Two c-type cytochromes were purified ( approximately 24 and approximately 6 kDa), and the 24-kDa protein (cytc-Ts4) was shown to donate electrons to SerABC in vitro. Protein sequence of cytc-Ts4 was obtained by N-terminal sequencing and liquid chromatography-tandem mass spectrometry analysis, and based upon sequence similarities, was assigned as a member of cytochrome c(4) family. Redox potentiometry, combined with UV-visible spectroscopy, showed that cytc-Ts4 is a diheme cytochrome with a redox potential of +282 +/- 10 mV, and both hemes are predicted to have His-Met ligation. To identify the membrane-bound electron donors to cytc-Ts4, growth of T. selenatis in the presence of respiratory inhibitors was monitored. The specific quinol-cytochrome c oxidoreductase (QCR) inhibitors myxothiazol and antimycin A partially inhibited selenate respiration, demonstrating that some electron flux is via the QCR. Electron transfer via a QCR and a diheme cytochrome c(4) is a novel route for a member of the DMSO reductase family of molybdoenzymes.
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Affiliation(s)
- Elisabeth C. Lowe
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Sarah Bydder
- the Department of Microbiology, La Trobe University, 3086 Victoria, Australia
| | - Robert S. Hartshorne
- the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Hannah L. U. Tape
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Elizabeth J. Dridge
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Charles M. Debieux
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Konrad Paszkiewicz
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Ian Singleton
- the Institute for Research on Environment and Sustainability, University of Newcastle, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Richard J. Lewis
- the Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, United Kingdom, and
| | - Joanne M. Santini
- the Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - David J. Richardson
- the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Clive S. Butler
- From the School of Biosciences, Centre for Biocatalysis, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
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32
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Azai C, Tsukatani Y, Itoh S, Oh-oka H. C-type cytochromes in the photosynthetic electron transfer pathways in green sulfur bacteria and heliobacteria. Photosynth Res 2010; 104:189-199. [PMID: 20091230 DOI: 10.1007/s11120-009-9521-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 12/17/2009] [Indexed: 05/28/2023]
Abstract
Green sulfur bacteria and heliobacteria are strictly anaerobic phototrophs that have homodimeric type 1 reaction center complexes. Within these complexes, highly reducing substances are produced through an initial charge separation followed by electron transfer reactions driven by light energy absorption. In order to attain efficient energy conversion, it is important for the photooxidized reaction center to be rapidly rereduced. Green sulfur bacteria utilize reduced inorganic sulfur compounds (sulfide, thiosulfate, and/or sulfur) as electron sources for their anoxygenic photosynthetic growth. Membrane-bound and soluble cytochromes c play essential roles in the supply of electrons from sulfur oxidation pathways to the P840 reaction center. In the case of gram-positive heliobacteria, the photooxidized P800 reaction center is rereduced by cytochrome c-553 (PetJ) whose N-terminal cysteine residue is modified with fatty acid chains anchored to the cytoplasmic membrane.
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Affiliation(s)
- Chihiro Azai
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
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33
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Navarro A, Boveris A, Bández MJ, Sánchez-Pino MJ, Gómez C, Muntané G, Ferrer I. Human brain cortex: mitochondrial oxidative damage and adaptive response in Parkinson disease and in dementia with Lewy bodies. Free Radic Biol Med 2009; 46:1574-80. [PMID: 19298851 DOI: 10.1016/j.freeradbiomed.2009.03.007] [Citation(s) in RCA: 286] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 02/21/2009] [Accepted: 03/04/2009] [Indexed: 10/21/2022]
Abstract
Frontal cortex samples from frozen human brains were used to assess tissue respiration; content of mitochondria; mitochondrial oxygen uptake; activity of respiratory complexes and of mitochondrial nitric oxide synthase (mtNOS); content of cytochromes a, b, and c; oxidative damage (protein carbonyls and TBARS); and expression of Mn-SOD in patients with Parkinson disease (PD) and with dementia with Lewy bodies (DLB) in comparison with those of normal healthy controls. Brain cortex and mitochondrial O(2) uptake and complex I activity were significantly lower in PD and DLB, whereas mtNOS activity, cytochrome content, expression of Mn-SOD, mitochondrial mass, and oxidative damage were significantly higher in the frontal cortex in PD and DLB. The decreases in tissue and mitochondrial O(2) uptake and in complex I activity are considered the consequences of mitochondrial oxidative damage. The increases in mtNOS activity and in mitochondrial mass are interpreted as an adaptive response of the frontal cortex that involves increased NO signaling for mitochondrial biogenesis. The adaptive response would partially compensate for mitochondrial dysfunction in these neurodegenerative diseases and would afford a human evolutionary response to shortage of ATP in the frontal cortex.
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Affiliation(s)
- Ana Navarro
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Cádiz, 11003 Cádiz, Spain.
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34
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Emory JF, Hassell KH, Londry FA, McLuckey SA. Transmission mode ion/ion reactions in the radiofrequency-only ion guide of hybrid tandem mass spectrometers. Rapid Commun Mass Spectrom 2009; 23:409-18. [PMID: 19125429 PMCID: PMC2744434 DOI: 10.1002/rcm.3894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Transmission mode ion/ion reactions have been performed within the first quadrupole, the Q0 radiofrequency (RF)-only quadrupole, of two types of hybrid tandem mass spectrometers (viz., triple quadrupole/linear ion trap and QqTOF instruments). These transmission mode reactions involved the storage of either the reagent species and the transmission of the analyte species through the Q0 quadrupole for charge inversion reactions or the storage of the analyte ions and transmission of the reagent ions as in charge reduction experiments. A key advantage to the use of transmission mode ion/ion reactions is that they do not require any instrument hardware modifications to provide interactions of oppositely charged ions and can be implemented in any instrument that contains a quadrupole or linear ion trap. The focus of this work was to investigate the potential of using the RF-only quadrupole ion guide positioned prior to the first mass-resolving element in a tandem mass spectrometer for ion/ion reactions. Two types of exemplary experiments have been demonstrated. One involved a charge inversion reaction and the other involved a charge reduction reaction in conjunction with ion parking. Ion/ion reactions proved to be readily implemented in Q0 thereby adding significantly greater experimental flexibility in the use of ion/ion reaction experiments with hybrid tandem mass spectrometers.
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Affiliation(s)
- Joshua F. Emory
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA
| | - Kerry H. Hassell
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA
| | - Frank A. Londry
- MDS SCIEX, 71 Four Valley Drive, Concord, Ontario, Canada L4K4V8
| | - Scott A. McLuckey
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA
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35
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Zoppellaro G, Harbitz E, Kaur R, Ensign AA, Bren KL, Andersson KK. Modulation of the ligand-field anisotropy in a series of ferric low-spin cytochrome c mutants derived from Pseudomonas aeruginosa cytochrome c-551 and Nitrosomonas europaea cytochrome c-552: a nuclear magnetic resonance and electron paramagnetic resonance study. J Am Chem Soc 2008; 130:15348-60. [PMID: 18947229 PMCID: PMC2664661 DOI: 10.1021/ja8033312] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytochromes of the c type with histidine-methionine (His-Met) heme axial ligation play important roles in electron-transfer reactions and in enzymes. In this work, two series of cytochrome c mutants derived from Pseudomonas aeruginosa (Pa c-551) and from the ammonia-oxidizing bacterium Nitrosomonas europaea (Ne c-552) were engineered and overexpressed. In these proteins, point mutations were induced in a key residue (Asn64) near the Met axial ligand; these mutations have a considerable impact both on heme ligand-field strength and on the Met orientation and dynamics (fluxionality), as judged by low-temperature electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectra. Ne c-552 has a ferric low-spin (S = 1/2) EPR signal characterized by large g anisotropy with g(max) resonance at 3.34; a similar large g(max) value EPR signal is found in the mitochondrial complex III cytochrome c1. In Ne c-552, deletion of Asn64 (NeN64Delta) changes the heme ligand field from more axial to rhombic (small g anisotropy and g(max) at 3.13) and furthermore hinders the Met fluxionality present in the wild-type protein. In Pa c-551 (g(max) at 3.20), replacement of Asn64 with valine (PaN64V) induces a decrease in the axial strain (g(max) at 3.05) and changes the Met configuration. Another set of mutants prepared by insertion (ins) and/or deletion (Delta) of a valine residue adjacent to Asn64, resulting in modifications in the length of the axial Met-donating loop (NeV65Delta, NeG50N/V65Delta, PaN50G/V65ins), did not result in appreciable alterations of the originally weak (Ne c-552) or very weak (Pa c-551) axial field but had an impact on Met orientation, fluxionality, and relaxation dynamics. Comparison of the electronic fingerprints in the overexpressed proteins and their mutants reveals a linear relationship between axial strain and average paramagnetic heme methyl shifts, irrespective of Met orientation or dynamics. Thus, for these His-Met axially coordinated Fe(III), the large g(max) value EPR signal does not represent a special case as is observed for bis-His axially coordinated Fe(III) with the two His planes perpendicular to each other.
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Affiliation(s)
- Giorgio Zoppellaro
- Department of Molecular Biosciences, University of Oslo, Post Office Box 1041 Blindern, Oslo NO-0316, Norway
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36
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Abstract
Electron transfer (ET) through and between proteins is a fundamental biological process. The rates of ET depend upon the thermodynamic driving force, the reorganization energy, and the degree of electronic coupling between the reactant and product states. The analysis of protein ET reactions is complicated by the fact that non-ET processes might influence the observed ET rate in kinetically complex biological systems. This Account describes studies of the methylamine dehydrogenase-amicyanin-cytochrome c-551i protein ET complex that have revealed the influence of several features of the protein structure on the magnitudes of the physical parameters for true ET reactions and how they dictate the kinetic mechanisms of non-ET processes that sometimes influence protein ET reactions. Kinetic and thermodynamic studies, coupled with structural information and biochemical data, are necessary to fully describe the ET reactions of proteins. Site-directed mutagenesis can be used to elucidate specific structure-function relationships. When mutations selectively alter the electronic coupling, reorganization energy, or driving force for the ET reaction, it becomes possible to use the parameters of the ET process to determine how specific amino acid residues and other features of the protein structure influence the ET rates. When mutations alter the kinetic mechanism for ET, one can determine the mechanisms by which non-ET processes, such as protein conformational changes or proton transfers, control the rates of ET reactions and how specific amino acid residues and certain features of the protein structure influence these non-ET reactions. A complete description of the mechanism of regulation of biological ET reactions enhances our understanding of metabolism, respiration, and photosynthesis at the molecular level. Such information has important medical relevance. Defective protein ET leads to production of the reactive oxygen species and free radicals that are associated with aging and many disease states. Defective ET within the respiratory chain also causes certain mitochondrial myopathies. An understanding of the mechanisms of regulation of protein ET is also of practical value because it provides a logical basis for the design of applications utilizing redox enzymes, such as enzyme-based electrode sensors and fuel cells.
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Affiliation(s)
- Victor L Davidson
- Department of Biochemistry, The University of Mississippi Medical Center, Jackson, Mississippi 39216-4505, USA.
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37
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Abstract
Hydrogen exchange rates for backbone amide protons of oxidized Pseudomonas aeruginosa cytochrome c-551 (P. aeruginosa cytochrome c) have been measured in the presence of low concentrations of the denaturant guanidine hydrochloride. Analysis of the data has allowed identification of submolecular unfolding units known as foldons. The highest-energy foldon bears similarity to the proposed folding intermediate for P. aeruginosa cytochrome c. Parallels are seen to the foldons of the structurally homologous horse cytochrome c, although the heme axial methionine-bearing loop has greater local stability in P. aeruginosa cytochrome c, in accord with previous folding studies. Regions of low local stability are observed to correspond with regions that interact with redox partners, providing a link between foldon properties and function.
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Affiliation(s)
- Lea V Michel
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, NY, 14642, USA
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Han D, Kim K, Oh J, Park J, Kim Y. TPR domain of NrfG mediates complex formation between heme lyase and formate‐dependent nitrite reductase in
Escherichia coli
O157:H7. Proteins 2008; 70:900-14. [PMID: 17803240 DOI: 10.1002/prot.21597] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Escherichia coli synthesize C-type cytochromes only during anaerobic growth in media supplemented with nitrate and nitrite. The reduction of nitrate to ammonium in the periplasm of Escherichia coli involves two separate periplasmic enzymes, nitrate reductase and nitrite reductase. The nitrite reductase involved, NrfA, contains cytochrome C and is synthesized coordinately with a membrane-associated cytochrome C, NrfB, during growth in the presence of nitrite or in limiting nitrate concentrations. The genes NrfE, NrfF, and NrfG are required for the formate-dependent nitrite reduction pathway, which involves at least two C-type cytochrome proteins, NrfA and NrfB. The NrfE, NrfF, and NrfG genes (heme lyase complex) are involved in the maturation of a special C-type cytochrome, apocytochrome C (apoNrfA), to cytochrome C (NrfA) by transferring a heme to the unusual heme binding motif of the Cys-Trp-Ser-Cys-Lys sequence in apoNrfA protein. Thus, in order to further investigate the roles of NrfG in the formation of heme lyase complex (NrfEFG) and in the interaction between heme lyase complex and formate-dependent nitrite reductase (NrfA), we determined the crystal structure of NrfG at 2.05 A. The structure of NrfG showed that the contact between heme lyase complex (NrfEFG) and NrfA is accomplished via a TPR domain in NrfG which serves as a binding site for the C-terminal motif of NrfA. The portion of NrfA that binds to TPR domain of NrfG has a unique secondary motif, a helix followed by about a six-residue C-terminal loop (the so called "hook conformation"). This study allows us to better understand the mechanism of special C-type cytochrome assembly during the maturation of formate-dependent nitrite reductase, and also adds a new TPR binding conformation to the list of TPR-mediated protein-protein interactions.
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Affiliation(s)
- Dohyun Han
- College of Medicine, Seoul National University, Yongon-Dong, Seoul 110-799, Korea
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39
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Branca RMM, Bodó G, Bagyinka C, Prokai L. De novo sequencing of a 21-kDa cytochrome c4 from Thiocapsa roseopersicina by nanoelectrospray ionization ion-trap and Fourier-transform ion-cyclotron resonance mass spectrometry. J Mass Spectrom 2007; 42:1569-1582. [PMID: 18085548 DOI: 10.1002/jms.1337] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We have determined the primary structure of cytochrome c(4) from Thiocapsa roseopersicina by de novo protein sequencing using the 'bottom up' approach. Three different enzymes (trypsin, endoproteinase Lys-C, and endoproteinase Glu-C) were employed to prepare four different sets of proteolytic digests. The digestion strategy was designed to permit a gradual buildup of smaller peptides into larger ones that were overlapped to yield the complete protein sequence. In this way we countered the main problem: peptides larger than about 1500 Da were difficult to sequence fully by tandem mass spectrometry. Direct infusion and online liquid chromatography were used on a linear ion trap Fourier-transform ion-cyclotron resonance hybrid instrument. The high resolving power, high mass accuracy and the availability of electron capture dissociation and collision-induced dissociation were essential to achieve full sequence coverage. The software DeNovoX complemented by manual interpretation was used to generate sequence information from tandem mass spectra. The predominantly automated nature of data acquisition and handling allowed for a relatively straightforward and fast procedure, which could compete with the mainstream alternative of nucleotide sequence determination.
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Affiliation(s)
- Rui Miguel Mamede Branca
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
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40
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Mukhopadhyay BP, Ghosh B, Bairagya HR, Bera AK, Nandi TK, Das SB. Modeling Study of Rusticyanin-Cytochrome C4Complex: An Insight to Possible H-Bond Mediated Recognition and Electron—Transfer Process. J Biomol Struct Dyn 2007; 25:157-64. [PMID: 17718594 DOI: 10.1080/07391102.2007.10507164] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Rusticyanin (RCy) mediated transfer of electron to Cytochrome C(4) (Cytc(4)) from the extracellular Fe(+2) ion is primarily involved in the Thiobacillus ferrooxidans induced bio-leaching of pyrite ore and also in the metabolism of this acidophilic bacteria. The modeling studies have revealed the two possible mode of RCy-Cytc(4) complexation involving nearly the same stabilization energy approximately -15 x 10(3) kJ/mol, one through N-terminal Asp 15 and another -C terminal Glu 121 of Cytc(4) with the Cu-bonded His 143 of RCy. The Asp 15:His 143 associated complex (DH) of Cytc(4)-RCy was stabilized by the intermolecular H-bonds of the carboxyl oxygen atoms O(delta1) and O(delta2) of Asp 15 with the Nepsilon-atom of His 143 and O(b) atoms of Ala 8 and Asp 5 (of Cytc(4)) with the Thr 146 and Phe 51 (of RCy). But the other Glu 121:His 143 associated complex (EH) of Cytc(4)-RCy was stabilized by the H-bonding interaction of the oxygen atoms O(epsilon1) and O(epsilon2) of Glu 121 with the Nepsilon and Ogamma atoms of His 143 and Thr 146 of RCy. The six water molecules were present in the binding region of the two proteins in the energy minimized autosolvated DH and EH-complexes. The MD studies also revealed the presence of six interacting water molecules at the binding region between the two proteins in both the complexes. Several residues Gly 82 and 84, His 143 (RCy) were participated through the water mediated (W 389, W 430, W 413, W 431, W 373, and W 478) interaction with the Asp 15, Ile 82, and 62, Tyr 63 (Cytc(4)) in DH complex, whereas in EH complex the Phe 51, Asn 80, Tyr 146 (RCy) residues were observed to interact with Asn 108, Met 120, Glu 121 (of Cytc(4)) through the water molecules W 507, W 445, W 401, W 446, and W 440. The direct water mediated (W 478) interaction of His 143 (RCy) to Asp 15 (of Cytc(4)) was observed only in the DH complex but not in EH. These direct and water mediated H-bonding between the two respective proteins and the binding free energy with higher interacting buried surface area of the DH complex compare to other EH complex have indicated an alternative possibility of the electron transfer route through the interaction of His 143 of RCy and the N-terminal Asp 15 of Cytc(4).
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Affiliation(s)
- B P Mukhopadhyay
- Department of Chemistry, National Institute Of Technology, Durgapur-713209, West Bengal, India.
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41
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Michel LV, Ye T, Bowman SEJ, Levin BD, Hahn MA, Russell BS, Elliott SJ, Bren KL. Heme attachment motif mobility tunes cytochrome c redox potential. Biochemistry 2007; 46:11753-60. [PMID: 17900177 PMCID: PMC2606054 DOI: 10.1021/bi701177j] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrogen exchange (HX) rates and midpoint potentials (Em) of variants of cytochrome c from Pseudomonas aeruginosa (Pa cyt c551) and Hydrogenobacter thermophilus (Ht cyt c552) have been characterized in an effort to develop an understanding of the impact of properties of the Cys-X-X-Cys-His pentapeptide c-heme attachment (CXXCH) motif on heme redox potential. Despite structural conservation of the CXXCH motif, Ht cyt c552 exhibits a low level of protection from HX for amide protons within this motif relative to Pa cyt c551. Site-directed mutants have been prepared to determine the structural basis for and functional implications of these variations on HX behavior. The double mutant Ht-M13V/K22M displays suppressed HX within the CXXCH motif as well as a decreased Em (by 81 mV), whereas the corresponding double mutant of Pa cyt c551 (V13M/M22K) exhibits enhanced HX within the CXXCH pentapeptide and a modest increase in Em (by 30 mV). The changes in Em correlate with changes in axial His chemical shifts in the ferric proteins reflecting the extent of histidinate character. Thus, the mobility of the CXXCH pentapeptide is found to impact the His-Fe(III) interaction and therefore the heme redox potential.
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Affiliation(s)
| | | | | | | | | | | | | | - Kara L. Bren
- To whom correspondence should be addressed: Department of Chemistry, University of Rochester, Rochester, NY 14627-0216. Telephone: (585) 275-4335. Fax: (585) 276-0205. e-mail:
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42
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Marshall MJ, Plymale AE, Kennedy DW, Shi L, Wang Z, Reed SB, Dohnalkova AC, Simonson CJ, Liu C, Saffarini DA, Romine MF, Zachara JM, Beliaev AS, Fredrickson JK. Hydrogenase- and outer membrane c-type cytochrome-facilitated reduction of technetium(VII) by Shewanella oneidensis MR-1. Environ Microbiol 2007; 10:125-36. [PMID: 17888007 DOI: 10.1111/j.1462-2920.2007.01438.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pertechnetate, (99)Tc(VII)O(4)(-), is a highly mobile radionuclide contaminant at US Department of Energy sites that can be enzymatically reduced by a range of anaerobic and facultatively anaerobic microorganisms, including Shewanella oneidensis MR-1, to poorly soluble Tc(IV)O(2(s)). In other microorganisms, Tc(VII)O(4)(-) reduction is generally considered to be catalysed by hydrogenase. Here, we provide evidence that although the NiFe hydrogenase of MR-1 was involved in the H(2)-driven reduction of Tc(VII)O(4)(-)[presumably through a direct coupling of H(2) oxidation and Tc(VII) reduction], the deletion of both hydrogenase genes did not completely eliminate the ability of MR-1 to reduce Tc(VII). With lactate as the electron donor, mutants lacking the outer membrane c-type cytochromes MtrC and OmcA or the proteins required for the maturation of c-type cytochromes were defective in reducing Tc(VII) to nanoparticulate TcO(2) x nH(2)O((s)) relative to MR-1 or a NiFe hydrogenase mutant. In addition, reduced MtrC and OmcA were oxidized by Tc(VII)O(4)(-), confirming the capacity for direct electron transfer from these OMCs to TcO(4)(-). c-Type cytochrome-catalysed Tc(VII) reduction could be a potentially important mechanism in environments where organic electron donor concentrations are sufficient to allow this reaction to dominate.
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Affiliation(s)
- Matthew J Marshall
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA.
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43
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Kresheck GC, Wang Z. A new micellar aqueous two-phase partitioning system (ATPS) for the separation of proteins. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 858:247-53. [PMID: 17884741 DOI: 10.1016/j.jchromb.2007.08.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 08/20/2007] [Accepted: 08/30/2007] [Indexed: 10/22/2022]
Abstract
Partitioning of six typical globular proteins with molecular weights ranging from 12.6 to 250 kDa was investigated using an aqueous two-phase system formed by heating a solution containing the individual proteins and n-dodecyldimethylphosphine oxide (APO12) above the cloud point of the nonionic surfactant (approximately 40 degrees C). The partition coefficient, Kp, was much greater at 55 than 45 degrees C and depended on both APO12 and protein concentrations. The value of Kp for bovine beta-lactoglobulin (beta-L) varied from 2 to 60, and was larger for 1.0mg/mL solutions than for ovalbumin (2x greater), bovine serum albumin (3x greater) and lysozyme (12x greater). Catalase and cytochrome c were apparently denatured in the presence of 20mg/mL of APO12 and were not investigated. Large values of Kp for beta-L resulted when the pH of APO12 mixtures containing phospholipids and either a cationic or anionic surfactant in molar ratios of 10:0.5:1.0 was partitioned above or below the isoelectric point of the protein, respectively. The affinity of the proteins for the APO12 micelle was responsible for partitioning of the proteins into the upper phase. Finally, DSC studies with beta-L showed that the denaturing action of n-decyldimethylphosphine oxide (APO10) below 61 degrees C and APO12 at 22 degrees C was reversed by dilution or dialysis, respectively.
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Affiliation(s)
- Gordon C Kresheck
- Department of Chemistry, University of Colorado at Colorado Springs, Colorado Springs, CO 80933-7150, USA.
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44
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Darain F, Park JS, Akutsu H, Shim YB. Superoxide radical sensing using a cytochrome c3 immobilized conducting polymer electrode. Biosens Bioelectron 2007; 23:161-7. [PMID: 17507210 DOI: 10.1016/j.bios.2007.03.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 02/08/2007] [Accepted: 03/28/2007] [Indexed: 11/30/2022]
Abstract
A biosensor based on cytochrome c3 (cyt c3) has been introduced to detect and quantify superoxide radical (O2*-). Cyt c3, isolated from the sulfate-reducing bacterium (Desulfovibrio vulgaris Miyazaki F. strain), and its mutant were immobilized onto a conducting polymer coated electrodes by the covalent bonding with carbodiimide chemistry. The immobilization of cyt c3 was investigated with quartz crystal microbalance, electrochemical impedance spectroscopy, and cyclic voltammetric studies. The CVs recorded for cyt c3 and a mutant modified-electrodes showed a quasi-reversible behavior having the formal potential of about -471 and -476 mV (versus Ag/AgCl), respectively, in a 0.1M phosphate buffer solution (pH 7.0). The modified electrodes showed the surface controlled process and the electron transfer rate constants (ks) were evaluated to be 0.47 and 0.51 s(-1) for cyt c3 and mutant modified electrodes, respectively. A potential application of the cyt c3 modified electrode was evaluated by monitoring the bioelectrocatalytic response towards the O2*-. The hydrodynamic range of 0.2-2.7 micromole L(-1) and the detection limit of 0.05 micromole L(-1) were obtained.
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Affiliation(s)
- Farzana Darain
- Department of Chemistry and Center for Innovative Bio-physio Sensor Technology, Pusan National University, Busan 609-735, South Korea
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45
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Hartshorne RS, Jepson BN, Clarke TA, Field SJ, Fredrickson J, Zachara J, Shi L, Butt JN, Richardson DJ. Characterization of Shewanella oneidensis MtrC: a cell-surface decaheme cytochrome involved in respiratory electron transport to extracellular electron acceptors. J Biol Inorg Chem 2007; 12:1083-94. [PMID: 17701062 DOI: 10.1007/s00775-007-0278-y] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 07/09/2007] [Indexed: 10/23/2022]
Abstract
MtrC is a decaheme c-type cytochrome associated with the outer cell membrane of Fe(III)-respiring species of the Shewanella genus. It is proposed to play a role in anaerobic respiration by mediating electron transfer to extracellular mineral oxides that can serve as terminal electron acceptors. The present work presents the first spectropotentiometric and voltammetric characterization of MtrC, using protein purified from Shewanella oneidensis MR-1. Potentiometric titrations, monitored by UV-vis absorption and electron paramagnetic resonance (EPR) spectroscopy, reveal that the hemes within MtrC titrate over a broad potential range spanning between approximately +100 and approximately -500 mV (vs. the standard hydrogen electrode). Across this potential window the UV-vis absorption spectra are characteristic of low-spin c-type hemes and the EPR spectra reveal broad, complex features that suggest the presence of magnetically spin-coupled low-spin c-hemes. Non-catalytic protein film voltammetry of MtrC demonstrates reversible electrochemistry over a potential window similar to that disclosed spectroscopically. The voltammetry also allows definition of kinetic properties of MtrC in direct electron exchange with a solid electrode surface and during reduction of a model Fe(III) substrate. Taken together, the data provide quantitative information on the potential domain in which MtrC can operate.
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Affiliation(s)
- Robert S Hartshorne
- Centre for Metalloprotein Spectroscopy and Biology, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
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46
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Rodrigues T, de França LP, Kawai C, de Faria PA, Mugnol KCU, Braga FM, Tersariol ILS, Smaili SS, Nantes IL. Protective Role of Mitochondrial Unsaturated Lipids on the Preservation of the Apoptotic Ability of Cytochrome c Exposed to Singlet Oxygen. J Biol Chem 2007; 282:25577-87. [PMID: 17567586 DOI: 10.1074/jbc.m700009200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytochrome c-mediated apoptosis in cells submitted to photodynamic therapy raises the question about the ability of photodynamically oxidized cytochrome c (cytc405) to trigger apoptosis as well as the effect of membranes on protein photo-oxidation. Cytochrome c was submitted to irradiation in the presence of MB+ in phosphate buffer and in the presence of four types of phosphatidylcholine/phosphatidylethanolamine/cardiolipin (PCPECL) liposomes (50/30/20%): totally saturated lipids (tsPCPECL), totally unsaturated lipids (tuPCPECL), partially unsaturated (80%) lipids, with unsaturation in the PC and PE content (puPCPECL80), and partially unsaturated (20%) lipids, with unsaturation in the CL content (puPCPECL20). Cytc405 was formed by irradiation in buffered water and in tsPCPECL and puPCPECL20 liposomes. In the presence of tuPCPECL and puPCPECL80, cytochrome c was protected from photodynamic damage (lipid-protected cytochrome c). In CL liposomes, 25% unsaturated lipids were enough to protect cytochrome c. The presence of unsaturated lipids, in amounts varying according to the liposome composition, are crucial to protect cytochrome c. Interesting findings corroborating the unsaturated lipids as cytochrome c protectors were obtained from the analysis of the lipid-oxidized derivatives of the samples. Native cytochrome c, lipid-protected cytochrome c, and cytc405 were microinjected in aortic smooth muscle cells. Apoptosis, characterized by nucleus blebbing and chromatin condensation, was detected in cells loaded with native and lipid protected cytochrome c but not in cells loaded with cytc405. These results suggest that photodynamic therapy-promoted apoptosis is feasible due to the protective effect of the mitochondrial lipids on the cytochrome c structure and function.
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Affiliation(s)
- Tiago Rodrigues
- Centro Interdisciplinar de Investigação Bioquímica Universidade de Mogi das Cruzes, Prédio I, Sala 1S-15, Mogi das Cruzes 08780-911, São Paulo, Brazil
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47
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Ogawa K, Sonoyama T, Takeda T, Ichiki SI, Nakamura S, Kobayashi Y, Uchiyama S, Nakasone K, Takayama SIJ, Mita H, Yamamoto Y, Sambongi Y. Roles of a short connecting disulfide bond in the stability and function of psychrophilic Shewanella violacea cytochrome c (5). Extremophiles 2007; 11:797-807. [PMID: 17657404 DOI: 10.1007/s00792-007-0099-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Accepted: 06/15/2007] [Indexed: 10/23/2022]
Abstract
Cys-59 and Cys-62, forming a disulfide bond in the four-residue loop of Shewanella violacea cytochrome c (5) (SV cytc (5)), contribute to protein stability but not to redox function. These Cys residues were substituted with Ala in SV cytc (5), and the structural and functional properties of the resulting C59A/C62A variant were determined and compared with those of the wild-type. The variant had similar features to those of the wild-type in absorption, circular dichroic, and paramagnetic (1)H NMR spectra. In addition, the redox potentials of the wild-type and variant were essentially the same, indicating that removal of the disulfide bond from SV cytc (5) does not affect the redox function generated in the vicinity of heme. However, calorimetric analysis of the wild-type and variant showed that the mutations caused a drastic decrease in the protein stability through enthalpy, but not entropy. Four residues are encompassed by the SV cytc (5) disulfide bond, which is the shortest one that has been proved to affect protein stability. The protein stability of SV cytc (5) can be controlled without changing the redox function, providing a new strategy for regulating the stability and function of cytochrome c.
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Affiliation(s)
- Keiko Ogawa
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8528, Japan
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48
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Takayama SIJ, Takahashi YT, Mikami SI, Irie K, Kawano S, Yamamoto Y, Hemmi H, Kitahara R, Yokoyama S, Akasaka K. Local Conformational Transition of Hydrogenobacter thermophilus Cytochrome c552 Relevant to Its Redox Potential,. Biochemistry 2007; 46:9215-24. [PMID: 17658890 DOI: 10.1021/bi7000714] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In order to elucidate the molecular mechanisms responsible for the apparent nonlinear behavior of the temperature dependence of the redox potential of Hydrogenobacter thermophilus cytochrome c552 [Takahashi, Y., Sasaki, H., Takayama, S. J., Mikami, S., Kawano, S., Mita, H., Sambongi, Y., and Yamamoto, Y. (2006) Biochemistry 45, 11005-11011], its heme active site structure has been characterized using variable-temperature and -pressure NMR techniques. The study revealed a temperature-dependent conformational transition between protein structures, which slightly differ in the conformation of the loop bearing the Fe-bound axial Met residue. The heme environment in the protein structure which arises at lower temperature was found to be more polar, as a result of the altered orientation of the loop with respect to the heme due to its conformational change, than that arising at higher temperature. The present study demonstrated the importance of the structural and dynamic properties of the polypeptide chain in close proximity to the heme for redox regulation of the protein.
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Zoppellaro G, Teschner T, Harbitz E, Schünemann V, Karlsen S, Arciero DM, Ciurli S, Trautwein AX, Hooper AB, Andersson KK. Low-temperature EPR and Mössbauer spectroscopy of two cytochromes with His-Met axial coordination exhibiting HALS signals. Chemphyschem 2007; 7:1258-67. [PMID: 16688708 DOI: 10.1002/cphc.200500693] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
C-type cytochromes with histidine-methionine (His-Met) iron coordination play important roles in electron-transfer reactions and in enzymes. Low-temperature electron paramagnetic resonance (EPR) spectra of low-spin ferric cytochromes c can be divided into two groups, depending on the spread of g values: the normal rhombic ones with small g anisotropy and g(max) below 3.2, and those featuring large g anisotropy with g(max) between 3.3 and 3.8, also denoted as highly axial low spin (HALS) species. Herein we present the detailed magnetic properties of cytochrome c(553) from Bacillus pasteurii (g(max) 3.36) and cytochrome c(552) from Nitrosomonas europaea (g(max) 3.34) over the pH range 6.2 to 8.2. Besides being structurally very similar, cytochrome c(553) shows the presence of a minor rhombic species at pH 6.2 (6 %), whereas cytochrome c(552) has about 25 % rhombic species over pH 7.5. The detailed Mössbauer analysis of cytochrome c(552) confirms the presence of these two low-spin ferric species (HALS and rhombic) together with an 8 % ferrous form with parameters comparable to the horse cytochrome c. Both EPR and Mössbauer data of axial cytochromes c with His-Met iron coordination are consistent with an electronic (d(xy))(2) (d(xz))(2) (d(yz))(1) ground state, which is typical for Type I model hemes.
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Affiliation(s)
- Giorgio Zoppellaro
- Department of Molecular Biosciences, University of Oslo, Box 1041 Blindern, 0316 Oslo, Norway
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Paquete CM, Turner DL, Louro RO, Xavier AV, Catarino T. Thermodynamic and kinetic characterisation of individual haems in multicentre cytochromes c3. Biochim Biophys Acta 2007; 1767:1169-79. [PMID: 17692816 DOI: 10.1016/j.bbabio.2007.06.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 06/25/2007] [Indexed: 11/27/2022]
Abstract
The characterisation of individual centres in multihaem proteins is difficult due to the similarities in the redox and spectroscopic properties of the centres. NMR has been used successfully to distinguish redox centres and allow the determination of the microscopic thermodynamic parameters in several multihaem cytochromes c(3) isolated from different sulphate-reducing bacteria. In this article we show that it is also possible to discriminate the kinetic properties of individual centres in multihaem proteins, if the complete microscopic thermodynamic characterisation is available and the system displays fast intramolecular equilibration in the time scale of the kinetic experiment. The deconvolution of the kinetic traces using a model of thermodynamic control provides a reference rate constant for each haem that does not depend on driving force and can be related to structural factors. The thermodynamic characterisation of three tetrahaem cytochromes and their kinetics of reduction by sodium dithionite are reported in this paper. Thermodynamic and kinetic data were fitted simultaneously to a model to obtain microscopic reduction potentials, haem-haem and haem-proton interacting potentials, and reference rate constants for the haems. The kinetic information obtained for these cytochromes and recently published data for other multihaem cytochromes is discussed with respect to the structural factors that determine the reference rates. The accessibility for the reducing agent seems to play an important role in controlling the kinetic rates, although is clearly not the only factor.
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Affiliation(s)
- Catarina M Paquete
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6, Apt. 127, 2780-156 Oeiras, Portugal
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