1
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Parson WW, Huang J, Kulke M, Vermaas JV, Kramer DM. Electron transfer in a crystalline cytochrome with four hemes. J Chem Phys 2024; 160:065101. [PMID: 38341797 DOI: 10.1063/5.0186958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/18/2024] [Indexed: 02/13/2024] Open
Abstract
Diffusion of electrons over distances on the order of 100 μm has been observed in crystals of a small tetraheme cytochrome (STC) from Shewanella oneidensis [J. Huang et al. J. Am. Chem. Soc. 142, 10459-10467 (2020)]. Electron transfer between hemes in adjacent subunits of the crystal is slower and more strongly dependent on temperature than had been expected based on semiclassical electron-transfer theory. We here explore explanations for these findings by molecular-dynamics simulations of crystalline and monomeric STC. New procedures are developed for including time-dependent quantum mechanical energy differences in the gap between the energies of the reactant and product states and for evaluating fluctuations of the electronic-interaction matrix element that couples the two hemes. Rate constants for electron transfer are calculated from the time- and temperature-dependent energy gaps, coupling factors, and Franck-Condon-weighted densities of states using an expression with no freely adjustable parameters. Back reactions are considered, as are the effects of various protonation states of the carboxyl groups on the heme side chains. Interactions with water are found to dominate the fluctuations of the energy gap between the reactant and product states. The calculated rate constant for electron transfer from heme IV to heme Ib in a neighboring subunit at 300 K agrees well with the measured value. However, the calculated activation energy of the reaction in the crystal is considerably smaller than observed. We suggest two possible explanations for this discrepancy. The calculated rate constant for transfer from heme I to II within the same subunit of the crystal is about one-third that for monomeric STC in solution.
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Affiliation(s)
- William W Parson
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | - Jingcheng Huang
- DOE-Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
| | - Martin Kulke
- DOE-Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
| | - Josh V Vermaas
- DOE-Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
| | - David M Kramer
- DOE-Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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2
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Hagen WR, Louro RO. A Comparative Multi-Frequency EPR Study of Dipolar Interaction in Tetra-Heme Cytochromes. Int J Mol Sci 2023; 24:12713. [PMID: 37628894 PMCID: PMC10454114 DOI: 10.3390/ijms241612713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
Distances between Fe ions in multiheme cytochromes are sufficiently short to make the intramolecular dipole-dipole interaction between hemes probable. In the analysis of EPR data from cytochromes, this interaction has thus far been ignored under the assumption that spectra are the simple sum of non-interacting components. Here, we use a recently developed low-frequency broadband EPR spectrometer to establish the extent of dipolar interaction in the example cytochromes, characterize its spectral signatures, and identify present limitations in the analysis. Broadband EPR spectra of Shewanella oneidensis MR-1 small tetraheme cytochrome (STC) have been collected over the frequency range of 0.45 to 13.11 GHz, and they have been compared to similar data from Desulfovibrio vulgaris Hildenborough cytochrome c3. The two cases are representative examples of two very different heme topologies and corresponding electron-transfer properties in tetraheme proteins. While in cytochrome c3, the six Fe-Fe distances can be sorted into two well-separated groups, those in STC are diffuse. Since the onset of dipolar interaction between Fe-Fe pairs is already observed in the X-band, the g values are determined in the simulation of the 13.11 GHz spectrum. Low-frequency spectra are analyzed with the inclusion of dipolar interaction based on available structural data on mutual distances and orientations between all hemes. In this procedure, all 24 possible assignments of individual heme spectra to heme topologies are sampled. The 24 configurations can be reduced to a few, but inspection falls short of a unique assignment, due to a remaining lack of understanding of the fine details of these complex spectra. In general, the EPR analysis suggests the four-heme system in c3 to be more rigid than that in STC, which is proposed to be related to different physiological roles in electron transfer.
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Affiliation(s)
- Wilfred R. Hagen
- Department of Biotechnology, Delft University of Technology, Building 58, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Ricardo O. Louro
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
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3
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Terai K, Yuly JL, Zhang P, Beratan DN. Correlated particle transport enables biological free energy transduction. Biophys J 2023; 122:1762-1771. [PMID: 37056051 PMCID: PMC10209040 DOI: 10.1016/j.bpj.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/17/2023] [Accepted: 04/07/2023] [Indexed: 04/15/2023] Open
Abstract
Studies of biological transport frequently neglect the explicit statistical correlations among particle site occupancies (i.e., they use a mean-field approximation). Neglecting correlations sometimes captures biological function, even for out-of-equilibrium and interacting systems. We show that neglecting correlations fails to describe free energy transduction, mistakenly predicting an abundance of slippage and energy dissipation, even for networks that are near reversible and lack interactions among particle sites. Interestingly, linear charge transport chains are well described without including correlations, even for networks that are driven and include site-site interactions typical of biological electron transfer chains. We examine three specific bioenergetic networks: a linear electron transfer chain (as found in bacterial nanowires), a near-reversible electron bifurcation network (as in complex III of respiration and other recently discovered structures), and a redox-coupled proton pump (as in complex IV of respiration).
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Affiliation(s)
- Kiriko Terai
- Department of Chemistry, Duke University, Durham, North Carolina
| | - Jonathon L Yuly
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersy
| | - Peng Zhang
- Department of Chemistry, Duke University, Durham, North Carolina
| | - David N Beratan
- Department of Chemistry, Duke University, Durham, North Carolina; Department of Physics, Duke University, Durham, North Carolina; Department of Biochemistry, Duke University, Durham, North Carolina.
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4
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Silva AV, Firmino MO, Costa NL, Louro RO, Paquete CM. Investigation of the Molecular Mechanisms of the Eukaryotic Cytochrome-c Maturation System. Biomolecules 2022; 12:biom12040549. [PMID: 35454139 PMCID: PMC9028165 DOI: 10.3390/biom12040549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 02/01/2023] Open
Abstract
Cytochromes-c are ubiquitous heme proteins with enormous impact at the cellular level, being key players in metabolic processes such as electron transfer chains and apoptosis. The assembly of these proteins requires maturation systems that catalyse the formation of the covalent thioether bond between two cysteine residues and the vinyl groups of the heme. System III is the maturation system present in Eukaryotes, designated CcHL or HCCS. This System requires a specific amino acid sequence in the apocytochrome to be recognized as a substrate and for heme insertion. To explore the recognition mechanisms of CcHL, the bacterial tetraheme cytochrome STC from Shewanella oneidensis MR-1, which is not a native substrate for System III, was mutated to be identified as a substrate. The results obtained show that it is possible to convert a bacterial cytochrome as a substrate by CcHL, but the presence of the recognition sequence is not the only factor that induces the maturation of a holocytochrome by System III. The location of this sequence in the polypeptide also plays a role in the maturation of the c-type cytochrome. Furthermore, CcHL appears to be able to catalyse the binding of only one heme per polypeptide chain, being unable to assemble multiheme cytochromes c, in contrast with bacterial maturation systems.
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5
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Sun W, Lin Z, Yu Q, Cheng S, Gao H. Promoting Extracellular Electron Transfer of Shewanella oneidensis MR-1 by Optimizing the Periplasmic Cytochrome c Network. Front Microbiol 2021; 12:727709. [PMID: 34675900 PMCID: PMC8524038 DOI: 10.3389/fmicb.2021.727709] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 09/13/2021] [Indexed: 11/13/2022] Open
Abstract
The low efficiency of extracellular electron transfer (EET) is a major bottleneck for Shewanella oneidensis MR-1 acting as an electroactive biocatalyst in bioelectrochemical systems. Although it is well established that a periplasmic c-type cytochrome (c-Cyt) network plays a critical role in regulating EET efficiency, the understanding of the network in terms of structure and electron transfer activity is obscure and partial. In this work, we attempted to systematically investigate the impacts of the network components on EET in their absence and overproduction individually in microbial fuel cell (MFC). We found that overexpression of c-Cyt CctA leads to accelerated electron transfer between CymA and the Mtr system, which function as the primary quinol oxidase and the outer-membrane (OM) electron hub in EET. In contrast, NapB, FccA, and TsdB in excess severely impaired EET, reducing EET capacity in MFC by more than 50%. Based on the results from both strategies, a series of engineered strains lacking FccA, NapB, and TsdB in combination while overproducing CctA were tested for a maximally optimized c-Cyt network. A strain depleted of all NapB, FccA, and TsdB with CctA overproduction achieved the highest maximum power density in MFCs (436.5 mW/m2), ∼3.62-fold higher than that of wild type (WT). By revealing that optimization of periplasmic c-Cyt composition is a practical strategy for improving EET efficiency, our work underscores the importance in understanding physiological and electrochemical characteristics of c-Cyts involved in EET.
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Affiliation(s)
- Weining Sun
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zhufan Lin
- Department of Energy Engineering, State Key Laboratory of Clean Energy, Zhejiang University, Hangzhou, China
| | - Qingzi Yu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shaoan Cheng
- Department of Energy Engineering, State Key Laboratory of Clean Energy, Zhejiang University, Hangzhou, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, China
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Nanosecond heme-to-heme electron transfer rates in a multiheme cytochrome nanowire reported by a spectrally unique His/Met-ligated heme. Proc Natl Acad Sci U S A 2021; 118:2107939118. [PMID: 34556577 PMCID: PMC8488605 DOI: 10.1073/pnas.2107939118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2021] [Indexed: 11/29/2022] Open
Abstract
Multiheme cytochromes have been identified as essential proteins for electron exchange between bacterial enzymes and redox substrates outside of the cell. In microbiology, these proteins contribute to efficient energy storage and conversion. For biotechnology, multiheme cytochromes contribute to the production of green fuels and electricity. Furthermore, these proteins inspire the design of molecular-scale electronic devices. Here, we report exceptionally high rates of heme-to-heme electron transfer in a multiheme cytochrome. We expect similarly high rates, among the highest reported for ground-state electron transfer in biology, in other multiheme cytochromes as the close-packed hemes adopt similar configurations despite very different amino acid sequences and protein folds. Proteins achieve efficient energy storage and conversion through electron transfer along a series of redox cofactors. Multiheme cytochromes are notable examples. These proteins transfer electrons over distance scales of several nanometers to >10 μm and in so doing they couple cellular metabolism with extracellular redox partners including electrodes. Here, we report pump-probe spectroscopy that provides a direct measure of the intrinsic rates of heme–heme electron transfer in this fascinating class of proteins. Our study took advantage of a spectrally unique His/Met-ligated heme introduced at a defined site within the decaheme extracellular MtrC protein of Shewanella oneidensis. We observed rates of heme-to-heme electron transfer on the order of 109 s−1 (3.7 to 4.3 Å edge-to-edge distance), in good agreement with predictions based on density functional and molecular dynamics calculations. These rates are among the highest reported for ground-state electron transfer in biology. Yet, some fall 2 to 3 orders of magnitude below the Moser–Dutton ruler because electron transfer at these short distances is through space and therefore associated with a higher tunneling barrier than the through-protein tunneling scenario that is usual at longer distances. Moreover, we show that the His/Met-ligated heme creates an electron sink that stabilizes the charge separated state on the 100-μs time scale. This feature could be exploited in future designs of multiheme cytochromes as components of versatile photosynthetic biohybrid assemblies.
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7
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Abstract
Hole hopping through tryptophan/tyrosine chains enables rapid unidirectional charge transport over long distances. We have elucidated structural and dynamical factors controlling hopping speed and efficiency in two modified azurin constructs that include a rhenium(I) sensitizer, Re(His)(CO)3(dmp)+, and one or two tryptophans (W1, W2). Experimental kinetics investigations showed that the two closely spaced (3 to 4 Å) intervening tryptophans dramatically accelerated long-range electron transfer (ET) from CuI to the photoexcited sensitizer. In our theoretical work, we found that time-dependent density-functional theory (TDDFT) quantum mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) trajectories of low-lying triplet excited states of ReI(His)(CO)3(dmp)+-W1(-W2) exhibited crossings between sensitizer-localized (*Re) and charge-separated [ReI(His)(CO)3(dmp•-)/(W1 •+ or W2 •+)] (CS1 or CS2) states. Our analysis revealed that the distances, angles, and mutual orientations of ET-active cofactors fluctuate in a relatively narrow range in which the cofactors are strongly coupled, enabling adiabatic ET. Water-dominated electrostatic field fluctuations bring *Re and CS1 states to a crossing where *Re(CO)3(dmp)+←W1 ET occurs, and CS1 becomes the lowest triplet state. ET is promoted by solvation dynamics around *Re(CO)3(dmp)+(W1); and CS1 is stabilized by Re(dmp•-)/W1 •+ electron/hole interaction and enhanced W1 •+ solvation. The second hop, W1 •+←W2, is facilitated by water fluctuations near the W1/W2 unit, taking place when the electrostatic potential at W2 drops well below that at W1 •+ Insufficient solvation and reorganization around W2 make W1 •+←W2 ET endergonic, shifting the equilibrium toward W1 •+ and decreasing the charge-separation yield. We suggest that multiscale TDDFT/MM/MD is a suitable technique to model the simultaneous evolution of photogenerated excited-state manifolds.
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Dai J, Knott GJ, Fu W, Lin TW, Furst AL, Britt RD, Francis MB. Protein-Embedded Metalloporphyrin Arrays Templated by Circularly Permuted Tobacco Mosaic Virus Coat Proteins. ACS NANO 2021; 15:8110-8119. [PMID: 33285072 DOI: 10.1021/acsnano.0c07165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Bioenergetic processes in nature have relied on networks of cofactors for harvesting, storing, and transforming the energy from sunlight into chemical bonds. Models mimicking the structural arrangement and functional crosstalk of the cofactor arrays are important tools to understand the basic science of natural systems and to provide guidance for non-natural functional biomaterials. Here, we report an artificial multiheme system based on a circular permutant of the tobacco mosaic virus coat protein (cpTMV). The double disk assembly of cpTMV presents a gap region sandwiched by the two C2-symmetrically related disks. Non-native bis-his coordination sites formed by the mutation of the residues in this gap region were computationally screened and experimentally tested. A cpTMV mutant Q101H was identified to create a circular assembly of 17 protein-embedded hemes. Biophysical characterization using X-ray crystallography, cyclic voltammetry, and electron paramagnetic resonance (EPR) suggested both structural and functional similarity to natural multiheme cytochrome c proteins. This protein framework offers many further engineering opportunities for tuning the redox properties of the cofactors and incorporating non-native components bearing varied porphyrin structures and metal centers. Emulating the electron transfer pathways in nature using a tunable artificial system can contribute to the development of photocatalytic materials and bioelectronics.
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Affiliation(s)
- Jing Dai
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Gavin J Knott
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
| | - Wen Fu
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Tiffany W Lin
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Late Stage Pharmaceutical Development, Genentech Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Ariel L Furst
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - R David Britt
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Matthew B Francis
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Materials Sciences Division and Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
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Faustino MM, Fonseca BM, Costa NL, Lousa D, Louro RO, Paquete CM. Crossing the Wall: Characterization of the Multiheme Cytochromes Involved in the Extracellular Electron Transfer Pathway of Thermincola ferriacetica. Microorganisms 2021; 9:microorganisms9020293. [PMID: 33572691 PMCID: PMC7911101 DOI: 10.3390/microorganisms9020293] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 12/13/2022] Open
Abstract
Bioelectrochemical systems (BES) are emerging as a suite of versatile sustainable technologies to produce electricity and added-value compounds from renewable and carbon-neutral sources using electroactive organisms. The incomplete knowledge on the molecular processes that allow electroactive organisms to exchange electrons with electrodes has prevented their real-world implementation. In this manuscript we investigate the extracellular electron transfer processes performed by the thermophilic Gram-positive bacteria belonging to the Thermincola genus, which were found to produce higher levels of current and tolerate higher temperatures in BES than mesophilic Gram-negative bacteria. In our study, three multiheme c-type cytochromes, Tfer_0070, Tfer_0075, and Tfer_1887, proposed to be involved in the extracellular electron transfer pathway of T. ferriacetica, were cloned and over-expressed in E. coli. Tfer_0070 (ImdcA) and Tfer_1887 (PdcA) were purified and biochemically characterized. The electrochemical characterization of these proteins supports a pathway of extracellular electron transfer via these two proteins. By contrast, Tfer_0075 (CwcA) could not be stabilized in solution, in agreement with its proposed insertion in the peptidoglycan wall. However, based on the homology with the outer-membrane cytochrome OmcS, a structural model for CwcA was developed, providing a molecular perspective into the mechanisms of electron transfer across the peptidoglycan layer in Thermincola.
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Huang J, Zarzycki J, Gunner MR, Parson WW, Kern JF, Yano J, Ducat DC, Kramer DM. Mesoscopic to Macroscopic Electron Transfer by Hopping in a Crystal Network of Cytochromes. J Am Chem Soc 2020; 142:10459-10467. [DOI: 10.1021/jacs.0c02729] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jingcheng Huang
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jan Zarzycki
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - M. R. Gunner
- Department of Physics, City College of New York, New York, New York 10031, United States
| | - William W. Parson
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States
| | - Jan F. Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Daniel C. Ducat
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - David M. Kramer
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
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11
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Lemaire ON, Méjean V, Iobbi-Nivol C. The Shewanella genus: ubiquitous organisms sustaining and preserving aquatic ecosystems. FEMS Microbiol Rev 2020; 44:155-170. [DOI: 10.1093/femsre/fuz031] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 01/09/2020] [Indexed: 12/16/2022] Open
Abstract
ABSTRACT
The Gram-negative Shewanella bacterial genus currently includes about 70 species of mostly aquatic γ-proteobacteria, which were isolated around the globe in a multitude of environments such as surface freshwater and the deepest marine trenches. Their survival in such a wide range of ecological niches is due to their impressive physiological and respiratory versatility. Some strains are among the organisms with the highest number of respiratory systems, depending on a complex and rich metabolic network. Implicated in the recycling of organic and inorganic matter, they are important components of organism-rich oxic/anoxic interfaces, but they also belong to the microflora of a broad group of eukaryotes from metazoans to green algae. Examples of long-term biological interactions like mutualism or pathogeny have been described, although molecular determinants of such symbioses are still poorly understood. Some of these bacteria are key organisms for various biotechnological applications, especially the bioremediation of hydrocarbons and metallic pollutants. The natural ability of these prokaryotes to thrive and detoxify deleterious compounds explains their use in wastewater treatment, their use in energy generation by microbial fuel cells and their importance for resilience of aquatic ecosystems.
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Affiliation(s)
- Olivier N Lemaire
- Aix-Marseille Université, Laboratoire de Bioénergétique et Ingénierie des Protéines, UMR 7281, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique, 13402 Marseille, France
| | - Vincent Méjean
- Aix-Marseille Université, Laboratoire de Bioénergétique et Ingénierie des Protéines, UMR 7281, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique, 13402 Marseille, France
| | - Chantal Iobbi-Nivol
- Aix-Marseille Université, Laboratoire de Bioénergétique et Ingénierie des Protéines, UMR 7281, Institut de Microbiologie de la Méditerranée, Centre National de la Recherche Scientifique, 13402 Marseille, France
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van Wonderen JH, Hall CR, Jiang X, Adamczyk K, Carof A, Heisler I, Piper SEH, Clarke TA, Watmough NJ, Sazanovich IV, Towrie M, Meech SR, Blumberger J, Butt JN. Ultrafast Light-Driven Electron Transfer in a Ru(II)tris(bipyridine)-Labeled Multiheme Cytochrome. J Am Chem Soc 2019; 141:15190-15200. [DOI: 10.1021/jacs.9b06858] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Jessica H. van Wonderen
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Christopher R. Hall
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Xiuyun Jiang
- Department of Physics and Astronomy and Thomas-Young Centre, University College London, London WC1E 6BT, United Kingdom
| | - Katrin Adamczyk
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Antoine Carof
- Department of Physics and Astronomy and Thomas-Young Centre, University College London, London WC1E 6BT, United Kingdom
| | - Ismael Heisler
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Samuel E. H. Piper
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Thomas A. Clarke
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Nicholas J. Watmough
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Igor V. Sazanovich
- Central Laser Facility, Research Complex at Harwell, Harwell Campus, Didcot, Oxon OX11 0QX, United Kingdom
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, Harwell Campus, Didcot, Oxon OX11 0QX, United Kingdom
| | - Stephen R. Meech
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Jochen Blumberger
- Department of Physics and Astronomy and Thomas-Young Centre, University College London, London WC1E 6BT, United Kingdom
- Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2 a, D-85748 Garching, Germany
| | - Julea N. Butt
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
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13
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Paquete CM, Rusconi G, Silva AV, Soares R, Louro RO. A brief survey of the "cytochromome". Adv Microb Physiol 2019; 75:69-135. [PMID: 31655743 DOI: 10.1016/bs.ampbs.2019.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Multihaem cytochromes c are widespread in nature where they perform numerous roles in diverse anaerobic metabolic pathways. This is achieved in two ways: multihaem cytochromes c display a remarkable diversity of ways to organize multiple hemes within the protein frame; and the hemes possess an intrinsic reactive versatility derived from diverse spin, redox and coordination states. Here we provide a brief survey of multihaem cytochromes c that have been characterized in the context of their metabolic role. The contribution of multihaem cytochromes c to dissimilatory pathways handling metallic minerals, nitrogen compounds, sulfur compounds, organic compounds and phototrophism are described. This aims to set the stage for the further exploration of the vast unknown "cytochromome" that can be anticipated from genomic databases.
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14
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Garg K, Ghosh M, Eliash T, van Wonderen JH, Butt JN, Shi L, Jiang X, Zdenek F, Blumberger J, Pecht I, Sheves M, Cahen D. Direct evidence for heme-assisted solid-state electronic conduction in multi-heme c-type cytochromes. Chem Sci 2018; 9:7304-7310. [PMID: 30294419 PMCID: PMC6166575 DOI: 10.1039/c8sc01716f] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/26/2018] [Indexed: 12/27/2022] Open
Abstract
Multi-heme cytochrome c (Cytc) proteins are key for transferring electrons out of cells, to enable intracellular oxidation to proceed in the absence of O2. In these proteins most of the hemes are arranged in a linear array suggesting a facile path for electronic conduction. To test this, we studied solvent-free electron transport across two multi-heme Cytc-type proteins: MtrF (deca-heme Cytc) and STC (tetra-heme Cytc). Transport is measured across monolayers of these proteins in a solid state configuration between Au electrodes. Both proteins showed 1000× higher conductance than single heme, or heme-free proteins, but similar conductance to monolayers of conjugated organics. Conductance is found to be temperature-independent (320-80 K), suggesting tunneling as the transport mechanism. This mechanism is consistent with I-V curves modelling, results of which could be interpreted by having protein-electrode coupling as rate limiting, rather than transport within the proteins.
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Affiliation(s)
- Kavita Garg
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , Israel .
| | - Mihir Ghosh
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , Israel .
| | - Tamar Eliash
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , Israel .
| | - Jessica H van Wonderen
- School of Chemistry , School of Biological Sciences , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK
| | - Julea N Butt
- School of Chemistry , School of Biological Sciences , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK
| | - Liang Shi
- Department of Biological Sciences and Technology , School of Environmental Sciences , China University of Geosciences , Wuhan , China 430074
| | - Xiuyun Jiang
- Department of Physics and Astronomy and Thomas Young Centre , University College London , Gower Street , London WC1E 6BT , UK
| | - Futera Zdenek
- Department of Physics and Astronomy and Thomas Young Centre , University College London , Gower Street , London WC1E 6BT , UK
| | - Jochen Blumberger
- Department of Physics and Astronomy and Thomas Young Centre , University College London , Gower Street , London WC1E 6BT , UK
| | - Israel Pecht
- Department of Immunology , Weizmann Institute of Science , Rehovot , Israel
| | - Mordechai Sheves
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , Israel .
| | - David Cahen
- Department of Materials and Interfaces , Weizmann Institute of Science , Rehovot , Israel .
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15
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van Wonderen JH, Li D, Piper SEH, Lau CY, Jenner LP, Hall CR, Clarke TA, Watmough NJ, Butt JN. Photosensitised Multiheme Cytochromes as Light-Driven Molecular Wires and Resistors. Chembiochem 2018; 19:2206-2215. [DOI: 10.1002/cbic.201800313] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Indexed: 01/12/2023]
Affiliation(s)
- Jessica H. van Wonderen
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Daobo Li
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
- Present address: Department of Chemistry; University of Science and Technology of China; Hefei 230026 China
- Present address: Collaborative Innovation Center of Suzhou Nano Science and Technology; Suzhou 215123 China
| | - Samuel E. H. Piper
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Cheuk Y. Lau
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Leon P. Jenner
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Christopher R. Hall
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
- Present address: ARC Centre of Excellence in Exciton Science; School of Chemistry; The University of Melbourne; Parkville Victoria 3010 Australia
| | - Thomas A. Clarke
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Nicholas J. Watmough
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
| | - Julea N. Butt
- School of Chemistry and School of Biology; University of East Anglia; Norwich Research Park Norfolk NR4 7TJ UK
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16
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Beblawy S, Bursac T, Paquete C, Louro R, Clarke TA, Gescher J. Extracellular reduction of solid electron acceptors by Shewanella oneidensis. Mol Microbiol 2018; 109:571-583. [PMID: 29995975 DOI: 10.1111/mmi.14067] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2018] [Indexed: 12/11/2022]
Abstract
Shewanella oneidensis is the best understood model organism for the study of dissimilatory iron reduction. This review focuses on the current state of our knowledge regarding this extracellular respiratory process and highlights its physiologic, regulatory and biochemical requirements. It seems that we have widely understood how respiratory electrons can reach the cell surface and what the minimal set of electron transport proteins to the cell surface is. Nevertheless, even after decades of work in different research groups around the globe there are still several important questions that were not answered yet. In particular, the physiology of this organism, the possible evolutionary benefit of some responses to anoxic conditions, as well as the exact mechanism of electron transfer onto solid electron acceptors are yet to be addressed. The elucidation of these questions will be a great challenge for future work and important for the application of extracellular respiration in biotechnological processes.
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Affiliation(s)
- Sebastian Beblawy
- Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (CS), Karlsruhe, Germany
| | - Thea Bursac
- Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (CS), Karlsruhe, Germany
| | - Catarina Paquete
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República-EAN, Oeiras, 2780-157, Portugal
| | - Ricardo Louro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República-EAN, Oeiras, 2780-157, Portugal
| | - Thomas A Clarke
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Johannes Gescher
- Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (CS), Karlsruhe, Germany.,Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
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17
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18
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Barrozo A, El-Naggar MY, Krylov AI. Distinct Electron Conductance Regimes in Bacterial Decaheme Cytochromes. Angew Chem Int Ed Engl 2018; 57:6805-6809. [PMID: 29663609 DOI: 10.1002/anie.201800294] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/28/2018] [Indexed: 12/12/2022]
Abstract
Shewanella oneidensis MR-1 gains energy by extracellular electron transfer to solid surfaces. They employ c-type cytochromes in two Mtr transmembrane complexes, forming a multiheme wire for electron transport across the cellular outer membrane. We investigated electron- and hole-transfer mechanisms in the external terminal of the two complexes, MtrC and MtrF. Comparison of computed redox potentials with previous voltammetry experiments in distinct environments (isolated and electrode-bound conditions of PFV or in vivo) suggests that these systems function in different regimes depending on the environment. Analysis of redox potential shifts in different regimes indicates strong coupling between the hemes via an interplay between direct Coulomb and indirect interactions through local structural reorganization. The latter results in the screening of Coulomb interactions and explains poor correlation of the strength of the heme-to-heme interactions with the distance between the hemes.
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Affiliation(s)
- Alexandre Barrozo
- Department of Chemistry, University of Southern California, Los Angeles, CA, 90089, USA
| | - Mohamed Y El-Naggar
- Department of Physics, University of Southern California, Los Angeles, CA, 90089, USA.,Department of Chemistry, University of Southern California, Los Angeles, CA, 90089, USA.,Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, CA, 90089, USA
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19
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Costa NL, Clarke TA, Philipp LA, Gescher J, Louro RO, Paquete CM. Electron transfer process in microbial electrochemical technologies: The role of cell-surface exposed conductive proteins. BIORESOURCE TECHNOLOGY 2018; 255:308-317. [PMID: 29444758 DOI: 10.1016/j.biortech.2018.01.133] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/26/2018] [Accepted: 01/27/2018] [Indexed: 06/08/2023]
Abstract
Electroactive microorganisms have attracted significant interest for the development of novel biotechnological systems of low ecological footprint. These can be used for the sustainable production of energy, bioremediation of metal-contaminated environments and production of added-value products. Currently, almost 100 microorganisms from the Bacterial and Archaeal domains are considered electroactive, given their ability to efficiently interact with electrodes in microbial electrochemical technologies. Cell-surface exposed conductive proteins are key players in the electron transfer between cells and electrodes. Interestingly, it seems that among the electroactive organisms identified so far, these cell-surface proteins fall into one of four groups. In this review, the different types of cell-surface conductive proteins found in electroactive organisms will be overviewed, focusing on their structural and functional properties.
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Affiliation(s)
- Nazua L Costa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República-EAN, 2780-157, Oeiras, Portugal
| | - Thomas A Clarke
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Laura-Alina Philipp
- Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (CS), Karlsruhe, Germany
| | - Johannes Gescher
- Department of Applied Biology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (CS), Karlsruhe, Germany; Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Ricardo O Louro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República-EAN, 2780-157, Oeiras, Portugal
| | - Catarina M Paquete
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República-EAN, 2780-157, Oeiras, Portugal.
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20
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Lai D, Khan FST, Rath SP. Multiheme proteins: effect of heme–heme interactions. Dalton Trans 2018; 47:14388-14401. [DOI: 10.1039/c8dt00518d] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This Frontier illustrates a brief personal account on the effect of heme–heme interactions in dihemes which thereby discloses some of the evolutionary design principles involved in multiheme proteins for their diverse structures and functions.
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Affiliation(s)
- Dipti Lai
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | | | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
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21
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Jiang X, Futera Z, Ali ME, Gajdos F, von Rudorff GF, Carof A, Breuer M, Blumberger J. Cysteine Linkages Accelerate Electron Flow through Tetra-Heme Protein STC. J Am Chem Soc 2017; 139:17237-17240. [DOI: 10.1021/jacs.7b08831] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Xiuyun Jiang
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Zdenek Futera
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Md. Ehesan Ali
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Fruzsina Gajdos
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Guido F. von Rudorff
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Antoine Carof
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Marian Breuer
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Jochen Blumberger
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
- Institute
for Advanced Study, Technische Universität München, Lichtenbergstrasse
2a, D-85748 Garching, Germany
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22
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Modulation of the reactivity of multiheme cytochromes by site-directed mutagenesis: moving towards the optimization of microbial electrochemical technologies. J Biol Inorg Chem 2016; 22:87-97. [DOI: 10.1007/s00775-016-1409-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/21/2016] [Indexed: 01/06/2023]
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23
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Rosa LFM, Hunger S, Gimkiewicz C, Zehnsdorf A, Harnisch F. Paving the way for bioelectrotechnology: Integrating electrochemistry into bioreactors. Eng Life Sci 2016; 17:77-85. [PMID: 32624731 DOI: 10.1002/elsc.201600105] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/17/2016] [Accepted: 06/14/2016] [Indexed: 11/05/2022] Open
Abstract
The reactor systems used for microbial electrosynthesis, i.e. bioelectrochemical systems for achieving bioproduction so far reported in literature are relatively small in scale and highly diverse in their architecture and modes of operation. The often diverging requirements of the electrochemical and the biological processes and the interdisciplinarity of the field make the engineering of these systems a special challenge. This has led to multiple, differently optimized approaches of reactor vessels, designs and operating conditions making standardization and normalization or even a systematic engineering almost impossible. Overcoming this lack of standardization, scalability and knowledge-driven engineering is the driving force for this work introducing an upgrade kit for bioreactors transforming these reversibly to bioelectroreactors. The prototypes of the bioreactor upgrade kit were integrated with commercial bioreactor (fermentor) systems and performances compared to a classic, small-scale bioelectrochemical glass cell system. The use of the upgrade kit allowed interfacing with the existing infrastructure of the conventional bioreactors for growing electroactive microorganisms in pure culture conditions, with the added electrochemical control and further process monitoring. The results of growing Shewanella oneidensis MR-1 clearly show that these systems can be used to control, monitor, and scale microbial bioelectrochemical processes, providing better resolution of the data for the tested experimental conditions.
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Affiliation(s)
- Luis F M Rosa
- Department of Environmental Microbiology Helmholtz-Centre for Environmental Research Leipzig Germany
| | - Steffi Hunger
- Centre for Environmental Biotechnology Helmholtz-Centre for Environmental Research Leipzig Germany
| | - Carla Gimkiewicz
- Department of Environmental Microbiology Helmholtz-Centre for Environmental Research Leipzig Germany
| | - Andreas Zehnsdorf
- Centre for Environmental Biotechnology Helmholtz-Centre for Environmental Research Leipzig Germany
| | - Falk Harnisch
- Department of Environmental Microbiology Helmholtz-Centre for Environmental Research Leipzig Germany
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24
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Alves MN, Neto SE, Alves AS, Fonseca BM, Carrêlo A, Pacheco I, Paquete CM, Soares CM, Louro RO. Characterization of the periplasmic redox network that sustains the versatile anaerobic metabolism of Shewanella oneidensis MR-1. Front Microbiol 2015; 6:665. [PMID: 26175726 PMCID: PMC4484225 DOI: 10.3389/fmicb.2015.00665] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 06/17/2015] [Indexed: 01/14/2023] Open
Abstract
The versatile anaerobic metabolism of the Gram-negative bacterium Shewanella oneidensis MR-1 (SOMR-1) relies on a multitude of redox proteins found in its periplasm. Most are multiheme cytochromes that carry electrons to terminal reductases of insoluble electron acceptors located at the cell surface, or bona fide terminal reductases of soluble electron acceptors. In this study, the interaction network of several multiheme cytochromes was explored by a combination of NMR spectroscopy, activity assays followed by UV-visible spectroscopy and comparison of surface electrostatic potentials. From these data the small tetraheme cytochrome (STC) emerges as the main periplasmic redox shuttle in SOMR-1. It accepts electrons from CymA and distributes them to a number of terminal oxidoreductases involved in the respiration of various compounds. STC is also involved in the electron transfer pathway to reduce nitrite by interaction with the octaheme tetrathionate reductase (OTR), but not with cytochrome c nitrite reductase (ccNiR). In the main pathway leading the metal respiration STC pairs with flavocytochrome c (FccA), the other major periplasmic cytochrome, which provides redundancy in this important pathway. The data reveals that the two proteins compete for the binding site at the surface of MtrA, the decaheme cytochrome inserted on the periplasmic side of the MtrCAB-OmcA outer-membrane complex. However, this is not observed for the MtrA homologues. Indeed, neither STC nor FccA interact with MtrD, the best replacement for MtrA, and only STC is able to interact with the decaheme cytochrome DmsE of the outer-membrane complex DmsEFABGH. Overall, these results shown that STC plays a central role in the anaerobic respiratory metabolism of SOMR-1. Nonetheless, the trans-periplasmic electron transfer chain is functionally resilient as a consequence of redundancies that arise from the presence of alternative pathways that bypass/compete with STC.
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Affiliation(s)
- Mónica N Alves
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
| | - Sónia E Neto
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
| | - Alexandra S Alves
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
| | - Bruno M Fonseca
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
| | - Afonso Carrêlo
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
| | - Isabel Pacheco
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
| | - Catarina M Paquete
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
| | - Cláudio M Soares
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
| | - Ricardo O Louro
- Inorganic Biochemistry and NMR Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa Oeiras, Portugal
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25
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Sturm-Richter K, Golitsch F, Sturm G, Kipf E, Dittrich A, Beblawy S, Kerzenmacher S, Gescher J. Unbalanced fermentation of glycerol in Escherichia coli via heterologous production of an electron transport chain and electrode interaction in microbial electrochemical cells. BIORESOURCE TECHNOLOGY 2015; 186:89-96. [PMID: 25812811 DOI: 10.1016/j.biortech.2015.02.116] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 02/27/2015] [Accepted: 02/28/2015] [Indexed: 05/28/2023]
Abstract
Microbial electrochemical cells are an emerging technology for achieving unbalanced fermentations. However, organisms that can serve as potential biocatalysts for this application are limited by their narrow substrate spectrum. This study describes the reprogramming of Escherichia coli for the efficient use of anodes as electron acceptors. Electron transfer into the periplasm was accelerated by 183% via heterologous expression of the c-type cytochromes CymA, MtrA and STC from Shewanella oneidensis. STC was identified as a target for heterologous expression via a two-stage screening approach. First, mass spectroscopic analysis revealed natively expressed cytochromes in S. oneidensis. Thereafter, the corresponding genes were cloned and expressed in E. coli to quantify periplasmic electron transfer activity using methylene blue. This redox dye was further used to expand electron transfer to carbon electrode surfaces. The results demonstrate that E. coli can be reprogrammed from glycerol fermentation to respiration upon production of the new electron transport chain.
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Affiliation(s)
- Katrin Sturm-Richter
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Frederik Golitsch
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Gunnar Sturm
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Elena Kipf
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, D-79110 Freiburg, Germany
| | - André Dittrich
- Institute of Photogrammetry and Remote Sensing, Englerstraße 7, D-76131 Karlsruhe, Germany
| | - Sebastian Beblawy
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Sven Kerzenmacher
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, D-79110 Freiburg, Germany
| | - Johannes Gescher
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany.
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26
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Daidone I, Paltrinieri L, Amadei A, Battistuzzi G, Sola M, Borsari M, Bortolotti CA. Unambiguous Assignment of Reduction Potentials in Diheme Cytochromes. J Phys Chem B 2014; 118:7554-7560. [DOI: 10.1021/jp506017a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Isabella Daidone
- Department
of Physical and Chemical Sciences, University of L’Aquila, via
Vetoio (Coppito 1), 67010 L’Aquila, Italy
| | - Licia Paltrinieri
- Department
of Chemical and Geological Sciences, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy
| | - Andrea Amadei
- Department
of Chemical Sciences and Technologies, University of Rome “Tor Vergata”, via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Gianantonio Battistuzzi
- Department
of Chemical and Geological Sciences, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy
| | - Marco Sola
- Department
of Life Sciences, University of Modena and Reggio Emilia, via Campi
183, 41125 Modena, Italy
- CNR-Nano Institute
of Nanoscience, via Campi 213/A, 41125 Modena, Italy
| | - Marco Borsari
- Department
of Chemical and Geological Sciences, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy
| | - Carlo Augusto Bortolotti
- Department
of Life Sciences, University of Modena and Reggio Emilia, via Campi
183, 41125 Modena, Italy
- CNR-Nano Institute
of Nanoscience, via Campi 213/A, 41125 Modena, Italy
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27
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Molecular mechanisms of heme based sensors from sediment organisms capable of extracellular electron transfer. J Inorg Biochem 2014; 133:104-9. [DOI: 10.1016/j.jinorgbio.2013.10.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/15/2013] [Accepted: 10/23/2013] [Indexed: 11/18/2022]
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28
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Paquete CM, Louro RO. Unveiling the details of electron transfer in multicenter redox proteins. Acc Chem Res 2014; 47:56-65. [PMID: 23984680 DOI: 10.1021/ar4000696] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metalloproteins modulate the intrinsic properties of transition metals to achieve controlled catalysis, electron transfer, or structural stabilization. Those performing electron transport, redox proteins, are a diverse class of proteins with central roles in numerous metabolic and signaling pathways, including respiration and photosynthesis. Many redox proteins have applications in industry, especially biotechnology, making them the focus of intense research. Redox proteins may contain one or multiple redox centers of the same or a different type. The complexity of proteins with multiple redox centers makes it difficult to establish a detailed molecular mechanism for their activity. Thermodynamic and kinetic information can be interpreted using the molecular structure to elucidate the protein's functional mechanism. This Account reviews experimental strategies developed in recent years to determine the detailed thermodynamic properties of multicenter redox proteins and their kinetic properties during interactions with redox partners. These strategies allow the discrimination of thermodynamic and kinetic properties of each individual redox center. The thermodynamic characterization of the redox transitions results from the combined analysis of data from NMR and UV-visible spectroscopy. Meanwhile, the kinetic characterization of intermolecular electron transfer comes from stopped-flow spectrophotometry. We illustrate an application of these strategies to a particular redox protein, the small tetraheme cytochrome from the periplasmic space of Shewanella oneidensis MR-1. This protein is a convenient prototype for developing methods for the detailed analysis of multicenter electron transfer proteins because hemes have strong UV-visible absorption bands and because heme resonances have exquisite discrimination in NMR spectra. Nonetheless, the methods are fully generalizable. Ultimately, this Account highlights the relevance of detailed characterization of the thermodynamic and kinetic properties of redox proteins. These properties are responsible for the directionality and specificity of the electron transfer process in bioenergetic pathways; a more thorough characterization of these properties should allow better-designed proteins for industrial applications.
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Affiliation(s)
- Catarina M. Paquete
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República (EAN), 2780-157 Oeiras, Portugal
| | - Ricardo O. Louro
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República (EAN), 2780-157 Oeiras, Portugal
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Neto SE, Fonseca BM, Maycock C, Louro RO. Analysis of the residual alignment of a paramagnetic multiheme cytochrome by NMR. Chem Commun (Camb) 2014; 50:4561-3. [DOI: 10.1039/c3cc49135h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Mind the gap: cytochrome interactions reveal electron pathways across the periplasm of Shewanella oneidensis MR-1. Biochem J 2012; 449:101-8. [DOI: 10.1042/bj20121467] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Extracellular electron transfer is the key metabolic trait that enables some bacteria to play a significant role in the biogeochemical cycling of metals and in bioelectrochemical devices such as microbial fuel cells. In Shewanella oneidensis MR-1, electrons generated in the cytoplasm by catabolic processes must cross the periplasmic space to reach terminal oxidoreductases found at the cell surface. Lack of knowledge on how these electrons flow across the periplasmic space is one of the unresolved issues related with extracellular electron transfer. Using NMR to probe protein–protein interactions, kinetic measurements of electron transfer and electrostatic calculations, we were able to identify protein partners and their docking sites, and determine the dissociation constants. The results showed that both STC (small tetrahaem cytochrome c) and FccA (flavocytochrome c) interact with their redox partners, CymA and MtrA, through a single haem, avoiding the establishment of stable redox complexes capable of spanning the periplasmic space. Furthermore, we verified that the most abundant periplasmic cytochromes STC, FccA and ScyA (monohaem cytochrome c5) do not interact with each other and this is likely to be the consequence of negative surface charges in these proteins. This reveals the co-existence of two non-mixing redox pathways that lead to extracellular electron transfer in S. oneidensis MR-1 established through transient protein interactions.
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31
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Saraiva IH, Newman DK, Louro RO. Functional characterization of the FoxE iron oxidoreductase from the photoferrotroph Rhodobacter ferrooxidans SW2. J Biol Chem 2012; 287:25541-8. [PMID: 22661703 DOI: 10.1074/jbc.m112.360636] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Photoferrotrophy is presumed to be an ancient type of photosynthetic metabolism in which bacteria use the reducing power of ferrous iron to drive carbon fixation. In this work the putative iron oxidoreductase of the photoferrotroph Rhodobacter ferrooxidans SW2 was cloned, purified, and characterized for the first time. This protein, FoxE, was characterized using spectroscopic, thermodynamic, and kinetic techniques. It is a c-type cytochrome that forms a trimer or tetramer in solution; the two hemes of each monomer are hexacoordinated by histidine and methionine. The hemes have positive reduction potentials that allow downhill electron transfer from many geochemically relevant ferrous iron forms to the photosynthetic reaction center. The reduction potentials of the hemes are different and are cross-assigned to fast and slow kinetic phases of ferrous iron oxidation in vitro. Lower reactivity was observed at high pH and may contribute to prevent ferric iron precipitation inside or at the surface of the cell. These results help fill in the molecular details of a metabolic process that likely contributed to the deposition of precambrian banded iron formations, globally important sedimentary rocks that are found on every continent today.
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Affiliation(s)
- Ivo H Saraiva
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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32
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Revealing the structural origin of the redox-Bohr effect: the first solution structure of a cytochrome from Geobacter sulfurreducens. Biochem J 2012; 441:179-87. [PMID: 21861844 DOI: 10.1042/bj20111103] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Gs (Geobacter sulfurreducens) can transfer electrons to the exterior of its cells, a property that makes it a preferential candidate for the development of biotechnological applications. Its genome encodes over 100 cytochromes and, despite their abundance and key functional roles, to date there is no structural information for these proteins in solution. The trihaem cytochrome PpcA might have a crucial role in the conversion of electronic energy into protonmotive force, a fundamental step for ATP synthesis in the presence of extracellular electron acceptors. In the present study, 15N-labelled PpcA was produced and NMR spectroscopy was used to determine its solution structure in the fully reduced state, its backbone dynamics and the pH-dependent conformational changes. The structure obtained is well defined, with an average pairwise rmsd (root mean square deviation) of 0.25 Å (1 Å=0.1 nm) for the backbone atoms and 0.99 Å for all heavy atoms, and constitutes the first solution structure of a Gs cytochrome. The redox-Bohr centre responsible for controlling the electron/proton transfer was identified, as well as the putative interacting regions between PpcA and its redox partners. The solution structure of PpcA will constitute the foundation for studies aimed at mapping out in detail these interacting regions.
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33
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Simulation of multihaem cytochromes. FEBS Lett 2011; 586:510-8. [DOI: 10.1016/j.febslet.2011.10.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 10/06/2011] [Accepted: 10/07/2011] [Indexed: 11/19/2022]
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34
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Fonseca BM, Paquete CM, Salgueiro CA, Louro RO. The role of intramolecular interactions in the functional control of multiheme cytochromes c. FEBS Lett 2011; 586:504-9. [PMID: 21856299 DOI: 10.1016/j.febslet.2011.08.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 08/09/2011] [Indexed: 10/17/2022]
Abstract
Detailed thermodynamic and structural data measured in soluble monomeric multiheme cytochromes c provided the basis to investigate the functional significance of interactions between redox co-factors. The steep decay of intramolecular interactions with distance means that close proximity of the redox centers is necessary to modulate the intrinsic reduction potentials in a significant way. This ensures selection of specific populations during redox activity in addition to maintaining fast intramolecular electron transfer. Therefore, intramolecular interactions between redox co-factors play an important role in establishing the biological function of the protein by controlling how electrons flow through and are distributed among the co-factors.
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Affiliation(s)
- Bruno M Fonseca
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157 Oeiras, Portugal
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35
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Dantas JM, Morgado L, Londer YY, Fernandes AP, Louro RO, Pokkuluri PR, Schiffer M, Salgueiro CA. Pivotal role of the strictly conserved aromatic residue F15 in the cytochrome c7 family. J Biol Inorg Chem 2011; 17:11-24. [PMID: 21805398 DOI: 10.1007/s00775-011-0821-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 07/09/2011] [Indexed: 10/17/2022]
Abstract
Cytochromes c(7) are periplasmic triheme proteins that have been reported exclusively in δ-proteobacteria. The structures of five triheme cytochromes identified in Geobacter sulfurreducens and one in Desulfuromonas acetoxidans have been determined. In addition to the hemes and axial histidines, a single aromatic residue is conserved in all these proteins-phenylalanine 15 (F15). PpcA is a member of the G. sulfurreducens cytochrome c(7) family that performs electron/proton energy transduction in addition to electron transfer that leads to the reduction of extracellular electron acceptors. For the first time we probed the role of the F15 residue in the PpcA functional mechanism, by replacing this residue with the aliphatic leucine by site-directed mutagenesis. The analysis of NMR spectra of both oxidized and reduced forms showed that the heme core and the overall fold of the mutated protein were not affected. However, the analysis of (1)H-(15)N heteronuclear single quantum coherence NMR spectra evidenced local rearrangements in the α-helix placed between hemes I and III that lead to structural readjustments in the orientation of heme axial ligands. The detailed thermodynamic characterization of F15L mutant revealed that the reduction potentials are more negative and the redox-Bohr effect is decreased. The redox potential of heme III is most affected. It is of interest that the mutation in F15, located between hemes I and III in PpcA, changes the characteristics of the two hemes differently. Altogether, these modifications disrupt the balance of the global network of cooperativities, preventing the F15L mutant protein from performing a concerted electron/proton transfer.
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Affiliation(s)
- Joana M Dantas
- Requimte-CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus Caparica, 2829-516 Caparica, Portugal
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36
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Qian Y, Paquete CM, Louro RO, Ross DE, Labelle E, Bond DR, Tien M. Mapping the iron binding site(s) on the small tetraheme cytochrome of Shewanella oneidensis MR-1. Biochemistry 2011; 50:6217-24. [PMID: 21682327 DOI: 10.1021/bi2005015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the model microbe Shewanella oneidensis, multi-heme proteins are utilized for respiratory metabolism where metals serve as the terminal electron acceptor. Among those is the periplasm-localized small tetraheme cytochrome (STC). STC has been extensively characterized structurally and electrochemically to which electron flow in and out of the protein has been modeled. However, until the present work, no kinetic studies have been performed to probe the route of electron flow or to determine the iron-binding site on STC. Using iron chelated by EDTA, NTA, or citrate, we have used chemical modification, site-directed mutagenesis along with isothermal titration calorimetry (ITC), and stopped-flow measurements to identify the iron binding site of STC. Chemical modifications of STC revealed that carboxyl groups on STC are involved in binding of EDTA-Fe(3+). Scanning mutagenesis was performed on Asp and Glu to probe the putative iron-binding site on STC. Two STC mutants (D21N; D80N) showed ∼70% decrease in observed electron transfer rate constant with EDTA-Fe(3+) from transient-state kinetic measurements. The impaired reactivity of STC (D80N/D21N) with EDTA-Fe(3+) was further confirmed by a significant decrease (>10-fold) in iron binding affinity.
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Affiliation(s)
- Yufeng Qian
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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37
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Mayfield JA, Dehner CA, DuBois JL. Recent advances in bacterial heme protein biochemistry. Curr Opin Chem Biol 2011; 15:260-6. [PMID: 21339081 DOI: 10.1016/j.cbpa.2011.02.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 02/01/2011] [Indexed: 01/01/2023]
Abstract
Recent progress in genetics, fed by the burst in genome sequence data, has led to the identification of a host of novel bacterial heme proteins that are now being characterized in structural and mechanistic terms. The following short review highlights very recent work with bacterial heme proteins involved in the uptake, biosynthesis, degradation, and use of heme in respiration and sensing.
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Affiliation(s)
- Jeffery A Mayfield
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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38
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Dantas JM, Saraiva IH, Morgado L, Silva MA, Schiffer M, Salgueiro CA, Louro RO. Orientation of the axial ligands and magnetic properties of the hemes in the cytochrome c7 family from Geobacter sulfurreducens determined by paramagnetic NMR. Dalton Trans 2011; 40:12713-8. [DOI: 10.1039/c1dt10975h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Morgado L, Bruix M, Pessanha M, Londer YY, Salgueiro CA. Thermodynamic characterization of a triheme cytochrome family from Geobacter sulfurreducens reveals mechanistic and functional diversity. Biophys J 2010; 99:293-301. [PMID: 20655858 DOI: 10.1016/j.bpj.2010.04.017] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/09/2010] [Accepted: 04/05/2010] [Indexed: 10/19/2022] Open
Abstract
A family of five periplasmic triheme cytochromes (PpcA-E) was identified in Geobacter sulfurreducens, where they play a crucial role by driving electron transfer from the cytoplasm to the cell exterior and assisting the reduction of extracellular acceptors. The thermodynamic characterization of PpcA using NMR and visible spectroscopies was previously achieved under experimental conditions identical to those used for the triheme cytochrome c(7) from Desulfuromonas acetoxidans. Under such conditions, attempts to obtain NMR data were complicated by the relatively fast intermolecular electron exchange. This work reports the detailed thermodynamic characterization of PpcB, PpcD, and PpcE under optimal experimental conditions. The thermodynamic characterization of PpcA was redone under these new conditions to allow a proper comparison of the redox properties with those of other members of this family. The heme reduction potentials of the four proteins are negative, differ from each other, and cover different functional ranges. These reduction potentials are strongly modulated by heme-heme interactions and by interactions with protonated groups (the redox-Bohr effect) establishing different cooperative networks for each protein, which indicates that they are designed to perform different functions in the cell. PpcA and PpcD appear to be optimized to interact with specific redox partners involving e(-)/H(+) transfer via different mechanisms. Although no evidence of preferential electron transfer pathway or e(-)/H(+) coupling was found for PpcB and PpcE, the difference in their working potential ranges suggests that they may also have different physiological redox partners. This is the first study, to our knowledge, to characterize homologous cytochromes from the same microorganism and provide evidence of their different mechanistic and functional properties. These findings provide an explanation for the coexistence of five periplasmic triheme cytochromes in G. sulfurreducens.
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Affiliation(s)
- Leonor Morgado
- Requimte-Centro de Química Fina e Biotecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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40
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Paquete CM, Saraiva IH, Calçada E, Louro RO. Molecular basis for directional electron transfer. J Biol Chem 2010; 285:10370-5. [PMID: 20089857 DOI: 10.1074/jbc.m109.078337] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Biological macromolecules involved in electron transfer reactions display chains of closely packed redox cofactors when long distances must be bridged. This is a consequence of the need to maintain a rate of transfer compatible with metabolic activity in the framework of the exponential decay of electron tunneling with distance. In this work intermolecular electron transfer was studied in kinetic experiments performed with the small tetraheme cytochrome from Shewanella oneidensis MR-1 and from Shewanella frigidimarina NCIMB400 using non-physiological redox partners. This choice allowed the effect of specific recognition and docking to be eliminated from the measured rates. The results were analyzed with a kinetic model that uses the extensive thermodynamic characterization of these proteins reported in the literature to discriminate the kinetic contribution of each heme to the overall rate of electron transfer. This analysis shows that, in this redox chain that spans 23 A, the kinetic properties of the individual hemes establish a functional specificity for each redox center. This functional specificity combined with the thermodynamic properties of these soluble proteins ensures directional electron flow within the cytochrome even outside of the context of a functioning respiratory chain.
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Affiliation(s)
- Catarina M Paquete
- Instituto de Tecnologia Química e Biológica, Av. da República (EAN), 2780-157 Oeiras, Portugal
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41
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Paquete CM, Louro RO. Molecular details of multielectron transfer: the case of multiheme cytochromes from metal respiring organisms. Dalton Trans 2009; 39:4259-66. [PMID: 20422082 DOI: 10.1039/b917952f] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Shewanella are facultative anaerobic bacteria of remarkable respiratory versatility that includes the dissimilatory reduction of metal ores. They contain a large number of multiheme c-type cytochromes that play a significant role in various anaerobic respiratory processes. Of all the cytochromes found in Shewanella, only the two most abundant periplasmic cytochromes, the small tetraheme cytochrome (STC) and flavocytochrome c(3) (Fcc(3)) have been structurally characterized. For these two proteins the molecular bases for their redox properties were determined using spectroscopic methods based on paramagnetic NMR, that allow the contribution of specific hemes to be discriminated. In this perspective these results are reviewed in the context of the continuing effort to understand the molecular mechanisms of electron transfer in the respiratory chains of these organisms.
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