1
|
Wilson LA, Melville JN, Pedroso MM, Krco S, Hoelzle R, Zaugg J, Southam G, Virdis B, Evans P, Supper J, Harmer JR, Tyson G, Clark A, Schenk G, Bernhardt PV. Kinetic, electrochemical and spectral characterization of bacterial and archaeal rusticyanins; unexpected stability issues and consequences for applications in biotechnology. J Inorg Biochem 2024; 256:112539. [PMID: 38593609 DOI: 10.1016/j.jinorgbio.2024.112539] [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: 01/24/2024] [Revised: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 04/11/2024]
Abstract
Motivated by the ambition to establish an enzyme-driven bioleaching pathway for copper extraction, properties of the Type-1 copper protein rusticyanin from Acidithiobacillus ferrooxidans (AfR) were compared with those from an ancestral form of this enzyme (N0) and an archaeal enzyme identified in Ferroplasma acidiphilum (FaR). While both N0 and FaR show redox potentials similar to that of AfR their electron transport rates were significantly slower. The lack of a correlation between the redox potentials and electron transfer rates indicates that AfR and its associated electron transfer chain evolved to specifically facilitate the efficient conversion of the energy of iron oxidation to ATP formation. In F. acidiphilum this pathway is not as efficient unless it is up-regulated by an as of yet unknown mechanism. In addition, while the electrochemical properties of AfR were consistent with previous data, previously unreported behavior was found leading to a form that is associated with a partially unfolded form of the protein. The cyclic voltammetry (CV) response of AfR immobilized onto an electrode showed limited stability, which may be connected to the presence of the partially unfolded state of this protein. Insights gained in this study may thus inform the engineering of optimized rusticyanin variants for bioleaching processes as well as enzyme-catalyzed solubilization of copper-containing ores such as chalcopyrite.
Collapse
Affiliation(s)
- Liam A Wilson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jamie N Melville
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Marcelo M Pedroso
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Stefan Krco
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert Hoelzle
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Julian Zaugg
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Gordon Southam
- School of the Environment, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Bernardino Virdis
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul Evans
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jenna Supper
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jeffrey R Harmer
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Gene Tyson
- Centre for Microbiome Research, Queensland University of Technology, Woolloongabba, QLD 4102, Australia
| | - Alice Clark
- Sustainable Minerals Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia; Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia; Sustainable Minerals Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
| |
Collapse
|
2
|
Ullrich SR, Fuchs H, Ashworth-Güth C. Electrochemical and structural characterization of recombinant respiratory proteins of the acidophilic iron oxidizer Ferrovum sp. PN-J47-F6 suggests adaptations to the acidic pH at protein level. Front Microbiol 2024; 15:1357152. [PMID: 38384274 PMCID: PMC10879576 DOI: 10.3389/fmicb.2024.1357152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 01/23/2024] [Indexed: 02/23/2024] Open
Abstract
The tendency of the periplasmic redox proteins in acidophiles to have more positive redox potentials (Em) than their homologous counterparts in neutrophiles suggests an adaptation to acidic pH at protein level, since thermodynamics of electron transfer processes are also affected by acidic pH. Since this conclusion is mainly based on the electrochemical characterization of redox proteins from extreme acidophiles of the genus Acidithiobacillus, we aimed to characterize three recombinant redox proteins of the more moderate acidophile Ferrovum sp. PN-J47-F6. We applied protein film voltammetry and linear sweep voltammetry coupled to UV/Vis spectroscopy to characterize the redox behavior of HiPIP-41, CytC-18, and CytC-78, respectively. The Em-values of HiPIP-41 (571 ± 16 mV), CytC-18 (276 ± 8 mV, 416 ± 2 mV), and CytC-78 (308 ± 7 mV, 399 ± 7 mV) were indeed more positive than those of homologous redox proteins in neutrophiles. Moreover, our findings suggest that the adaptation of redox proteins with respect to their Em occurs more gradually in response to the pH, since there are also differences between moderate and more extreme acidophiles. In order to address structure function correlations in these redox proteins with respect to structural features affecting the Em, we conducted a comparative structural analysis of the Ferrovum-derived redox proteins and homologs of Acidithiobacillus spp. and neutrophilic proteobacteria. Hydrophobic contacts in the redox cofactor binding pockets resulting in a low solvent accessibility appear to be the major factor contributing to the more positive Em-values in acidophile-derived redox proteins. While additional cysteines in HiPIPs of acidophiles might increase the effective shielding of the [4Fe-4S]-cofactor, the tight shielding of the heme centers in acidophile-derived cytochromes is achieved by a drastic increase in hydrophobic contacts (A.f. Cyc41), and by a larger fraction of aromatic residues in the binding pockets (CytC-18, CytC-78).
Collapse
Affiliation(s)
- Sophie R. Ullrich
- Environmental Microbiology Group, Institute for Biological Sciences, TU Bergakademie Freiberg, Freiberg, Germany
- Biohydrometallurgy Group, Institute for Biological Sciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Helena Fuchs
- Biohydrometallurgy Group, Institute for Biological Sciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Charlotte Ashworth-Güth
- Salt and Mineral Chemistry Group, Institute for Inorganic Chemistry, TU Bergakademie Freiberg, Freiberg, Germany
| |
Collapse
|
3
|
Ullrich SR, Fuchs H, Schlömann M. Shedding light on the electron transfer chain of a moderately acidophilic iron oxidizer: characterization of recombinant HiPIP-41, CytC-18 and CytC-78 derived from Ferrovum sp. PN-J47-F6. Res Microbiol 2024; 175:104088. [PMID: 37348744 DOI: 10.1016/j.resmic.2023.104088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/24/2023]
Abstract
Efficient electron transfer from the donor to the acceptor couple presents a necessary requirement for acidophilic and neutrophilic iron oxidizers due to the low energy yield of aerobic ferrous iron oxidation. Involved periplasmic electron carriers are very diverse in these bacteria and show adaptations to the respective thermodynamic constraints such as a more positive redox potential reported for extreme acidophilic Acidithiobacillus spp. Respiratory chain candidates of moderately acidophilic members of the genus Ferrovum share similarities with both their neutrophilic iron oxidizing relatives and the more distantly related Acidithiobacillus spp. We examined our previous omics-based conclusions on the potential electron transfer chain in Ferrovum spp. by characterizing the three redox protein candidates CytC-18, CytC-78 and HiPIP-41 of strain PN-J47-F6 which were produced as recombinant proteins in Eschericha coli. UV/Vis-based redox assays suggested that HiPIP-41 has a very positive redox potential while redox potentials of CytC-18 and CytC-78 are more negative than their counterparts in Acidithiobacillus spp. Far Western dot blotting demonstrated interactions between all three recombinant redox proteins while redox assays showed the electron transfer from HiPIP-41 to either of the cytochromes. Altogether, CytC-18, CytC-78 and HiPIP-41 indeed represent very likely candidates of the electron transfer in Ferrovum sp. PN-J4-F6.
Collapse
Affiliation(s)
- Sophie R Ullrich
- TU Bergakademie Freiberg, Institute for Biological Sciences, Leipziger Strasse 29, Freiberg, Germany.
| | - Helena Fuchs
- TU Bergakademie Freiberg, Institute for Biological Sciences, Leipziger Strasse 29, Freiberg, Germany
| | - Michael Schlömann
- TU Bergakademie Freiberg, Institute for Biological Sciences, Leipziger Strasse 29, Freiberg, Germany
| |
Collapse
|
4
|
Bulaev A, Kadnikov V, Elkina Y, Beletsky A, Melamud V, Ravin N, Mardanov A. Shifts in the Microbial Populations of Bioleach Reactors Are Determined by Carbon Sources and Temperature. BIOLOGY 2023; 12:1411. [PMID: 37998010 PMCID: PMC10669018 DOI: 10.3390/biology12111411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/06/2023] [Accepted: 11/06/2023] [Indexed: 11/25/2023]
Abstract
In the present study, the effect of additional carbon sources (carbon dioxide and molasses) on the bio-oxidation of a pyrite-arsenopyrite concentrate at temperatures of 40-50 °C was studied, and novel data regarding the patterns of the bio-oxidation of gold-bearing sulfide concentrates and the composition of the microbial populations performing these processes were obtained. At 40 °C, additional carbon sources did not affect the bio-oxidation efficiency. At the same time, the application of additional carbon dioxide improved the bio-oxidation performance at temperatures of 45 and 50 °C and made it possible to avoid the inhibition of bio-oxidation due to an increase in the temperature. Therefore, the use of additional carbon dioxide may be proposed to prevent the negative effect of an increase in temperature on the bio-oxidation of sulfide concentrates. 16S rRNA gene profiling revealed archaea of the family Thermoplasmataceae (Acidiplasma, Ferroplasma, Cuniculiplasma, and A-plasma group) and bacteria of the genera Leptospirillum, with Sulfobacillus and Acidithiobacillus among the dominant groups in the community. Temperature influenced the composition of the communities to a greater extent than the additional sources of carbon and the mode of operation of the bioreactor. Elevating the temperature from 40 °C to 50 °C resulted in increases in the shares of Acidiplasma and Sulfobacillus and decreases in the relative abundances of Ferroplasma, Leptospirillum, and Acidithiobacillus, while Cuniculiplasma and A-plasma were more abundant at 45 °C. A metagenomic analysis of the studied population made it possible to characterize novel archaea belonging to an uncultivated, poorly-studied group of Thermoplasmatales which potentially plays an important role in the bio-oxidation process. Based on an analysis of the complete genome, we propose describing the novel species and novel genus as "Candidatus Carboxiplasma ferriphilum" gen. nov., spec. nov.
Collapse
Affiliation(s)
- Aleksandr Bulaev
- Research Center of Biotechnology, The Russian Academy of Sciences, Leninsky Ave. 33 Bld. 2, 119071 Moscow, Russia; (V.K.); (Y.E.); (A.B.); (V.M.); (A.M.)
| | | | | | | | | | | | | |
Collapse
|
5
|
Evaluation of Cyc 1 protein stability in Acidithiobacillus ferrooxidans bacterium after E121D mutation by molecular dynamics simulation to improve electron transfer. JOURNAL OF MICROBIOLOGY (SEOUL, KOREA) 2022; 60:526-532. [PMID: 35286603 DOI: 10.1007/s12275-022-1645-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 10/18/2022]
Abstract
Cyc1 (Cytochrome c552) is a protein in the electron transport chain of the Acidithiobacillus ferrooxidans (Af) bacteria which obtain their energy from oxidation Fe2+ to Fe3+. The electrons are directed through Cyc2, RCY (rusticyanin), Cyc1 and Cox aa3 proteins to O2. Cyc1 protein consists of two chains, A and B. In the present study, a novel mutation (E121D) in the A chain of Cyc1 protein was selected due to electron receiving from Histidine 143 of RCY. Then, the changes performed in the E121D mutant were evaluated by MD simulations analyzes. Cyc1 and RCY proteins were docked by a Patchdock server. By E121D mutation, the connection between Zn 1388 of chain B and aspartate 121 of chain A weaken. Asp 121 gets farther from Zn 1388. Therefore, the aspartate gets closer to Cu 1156 of the RCY leading to the higher stability of the RCY/Cyc1 complex. Further, an acidic residue (Glu121) becomes a more acidic residue (Asp121) and improves the electron transfer to Cyc1 protein. The results of RMSF analysis showed further ligand flexibility in mutation. This leads to fluctuation of the active site and increases redox potential at the mutation point and the speed of electron transfer. This study also predicts that in all respiratory chain proteins, electrons probably enter the first active site via glutamate and exit histidine in the second active site of each respiratory chain protein.
Collapse
|
6
|
Malik L, Hedrich S. Ferric Iron Reduction in Extreme Acidophiles. Front Microbiol 2022; 12:818414. [PMID: 35095822 PMCID: PMC8790237 DOI: 10.3389/fmicb.2021.818414] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/17/2021] [Indexed: 11/13/2022] Open
Abstract
Biochemical processes are a key element of natural cycles occurring in the environment and enabling life on earth. With regard to microbially catalyzed iron transformation, research predominantly has focused on iron oxidation in acidophiles, whereas iron reduction played a minor role. Microbial conversion of ferric to ferrous iron has however become more relevant in recent years. While there are several reviews on neutrophilic iron reducers, this article summarizes the research on extreme acidophilic iron reducers. After the first reports of dissimilatory iron reduction by acidophilic, chemolithoautotrophic Acidithiobacillus strains and heterotrophic Acidiphilium species, many other prokaryotes were shown to reduce iron as part of their metabolism. Still, little is known about the exact mechanisms of iron reduction in extreme acidophiles. Initially, hypotheses and postulations for the occurring mechanisms relied on observations of growth behavior or predictions based on the genome. By comparing genomes of well-studied neutrophilic with acidophilic iron reducers (e.g., Ferroglobus placidus and Sulfolobus spp.), it became clear that the electron transport for iron reduction proceeds differently in acidophiles. Moreover, transcriptomic investigations indicated an enzymatically-mediated process in Acidithiobacillus ferrooxidans using respiratory chain components of the iron oxidation in reverse. Depending on the strain of At. ferrooxidans, further mechanisms were postulated, e.g., indirect iron reduction by hydrogen sulfide, which may form by disproportionation of elemental sulfur. Alternative scenarios include Hip, a high potential iron-sulfur protein, and further cytochromes. Apart from the anaerobic iron reduction mechanisms, sulfur-oxidizing acidithiobacilli have been shown to mediate iron reduction at low pH (< 1.3) under aerobic conditions. This presumably non-enzymatic process may be attributed to intermediates formed during sulfur/tetrathionate and/or hydrogen oxidation and has already been successfully applied for the reductive bioleaching of laterites. The aim of this review is to provide an up-to-date overview on ferric iron reduction by acidophiles. The importance of this process in anaerobic habitats will be demonstrated as well as its potential for application.
Collapse
Affiliation(s)
- Luise Malik
- Research Group Biohydrometallurgy and Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| | - Sabrina Hedrich
- Research Group Biohydrometallurgy and Microbiology, Institute of Biosciences, TU Bergakademie Freiberg, Freiberg, Germany
| |
Collapse
|
7
|
Blake RC, White RA. In situ absorbance measurements: a new means to study respiratory electron transfer in chemolithotrophic microorganisms. Adv Microb Physiol 2020; 76:81-127. [PMID: 32408948 DOI: 10.1016/bs.ampbs.2020.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Absorbance measurements on intact chemolithotrophic microorganisms that respire aerobically on soluble iron are described that used a novel integrating cavity absorption meter to eliminate the effects of light scattering on the experimental results. Steady state kinetic measurements on ferric iron production by intact cells revealed that the Michaelis Menten equation described the initial rates of product formation for at least 8 different chemolithotrophic microorganisms in 6 phyla distributed equally among the archaea and the Gram negative and Gram positive eubacteria. Cell-monitored turnover measurements during aerobic respiration on soluble iron by the same 12 intact microorganisms revealed six different patterns of iron-dependent absorbance changes, suggesting that there may be at least six different sets of prosthetic groups and biomolecules that can accomplish aerobic respiration on soluble iron. Detailed kinetic studies revealed that the 3-component iron respiratory chain of Acidithiobacillus ferrooxidans functioned as an ensemble with a single macroscopic rate constant when the iron-reduced proteins were oxidized in the presence of excess molecular oxygen. The principal member of this 3-component system was a cupredoxin called rusticyanin that was present in the periplasm of At. ferrooxidans at an approximate concentration of 350 mg/mL, an observation that provides new insights into the crowded environments in the periplasms of Gram negative eubacteria that conduct electrons across their periplasm. The ability to conduct direct spectrophotometric measurements under noninvasive physiological conditions represents a new and powerful approach to examine the rates and extents of biological events in situ without disrupting the complexity of the live cellular environment.
Collapse
Affiliation(s)
- Robert C Blake
- College of Pharmacy, Xavier University of Louisiana, New Orleans, United States
| | - Richard A White
- Department of Plant Pathology, Washington State University, Pullman, WA, United States; RAW Molecular Systems (RMS) LLC, Spokane, WA, United States; Australian Centre for Astrobiology, University of New South Wales, Sydney, NSW, Australia
| |
Collapse
|
8
|
Carpenter JM, Zhong F, Ragusa MJ, Louro RO, Hogan DA, Pletneva EV. Structure and redox properties of the diheme electron carrier cytochrome c 4 from Pseudomonas aeruginosa. J Inorg Biochem 2019; 203:110889. [PMID: 31707335 DOI: 10.1016/j.jinorgbio.2019.110889] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/26/2019] [Accepted: 10/14/2019] [Indexed: 02/02/2023]
Abstract
At low oxygen concentrations, respiration of Pseudomonas aeruginosa (Pa) and other bacteria relies on activity of cytochrome cbb3 oxidases. A diheme cytochrome c4 (cyt c4) donates electrons to Pa cbb3 oxidases to enable oxygen reduction and proton pumping by these enzymes. Given the importance of this redox pathway for bacterial pathogenesis, both cyt c4 and cbb3 oxidase are potential targets for new antibacterial strategies. The structural information about these two proteins, however, is scarce, and functional insights for Pa and other bacteria have been primarily drawn from analyses of the analogous system from Pseudomonas stutzeri (Ps). Herein, we describe characterization of structural and redox properties of cyt c4 from Pa. The crystal structure of Pa cyt c4 has revealed that this protein is organized in two monoheme domains. The interdomain interface is more hydrophobic in Pa cyt c4, and the protein surface does not show the dipolar distribution of charges found in Ps cyt c4. The reduction potentials of the two hemes are similar in Pa cyt c4 but differ by about 100 mV in Ps cyt c4. Analyses of structural models of these and other cyt c4 proteins suggest that multiple factors contribute to the potential difference of the two hemes in these proteins, including solvent accessibility of the heme group, the distribution of surface charges, and the nature of the interdomain interface. The distinct properties of cyt c4 proteins from closely-related Pa and Ps bacteria emphasize the importance of examining the cbb3/cyt c4 redox pathway in multiple species.
Collapse
Affiliation(s)
- Jessica M Carpenter
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, United States of America
| | - Fangfang Zhong
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, United States of America
| | - Michael J Ragusa
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, United States of America
| | - Ricardo O Louro
- Instituto de Tecnologia Química e Biologica, Anto ́nio Xavier, Universidade Nova de Lisboa, Av. da Repu ́blica (EAN), 2780-157 Oeiras, Portugal
| | - Deborah A Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, United States of America
| | - Ekaterina V Pletneva
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, United States of America.
| |
Collapse
|
9
|
Alvarez-Paggi D, Hannibal L, Castro MA, Oviedo-Rouco S, Demicheli V, Tórtora V, Tomasina F, Radi R, Murgida DH. Multifunctional Cytochrome c: Learning New Tricks from an Old Dog. Chem Rev 2017; 117:13382-13460. [DOI: 10.1021/acs.chemrev.7b00257] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Damián Alvarez-Paggi
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Luciana Hannibal
- Department
of Pediatrics, Universitätsklinikum Freiburg, Mathildenstrasse 1, Freiburg 79106, Germany
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - María A. Castro
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Santiago Oviedo-Rouco
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Veronica Demicheli
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Veronica Tórtora
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Florencia Tomasina
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Rafael Radi
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Daniel H. Murgida
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| |
Collapse
|
10
|
Fatemi F, Miri S, Jahani S. Effect of metal sulfide pulp density on gene expression of electron transporters in Acidithiobacillus sp. FJ2. Arch Microbiol 2016; 199:521-530. [PMID: 27885407 DOI: 10.1007/s00203-016-1318-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 10/21/2016] [Accepted: 11/04/2016] [Indexed: 11/30/2022]
Abstract
In Acidithiobacillus ferrooxidans, one of the most important bioleaching bacterial species, the proteins encoded by the rus operon are involved in the electron transfer from Fe2+ to O2. To obtain further knowledge about the mechanism(s) involved in the adaptive responses of the bacteria to growth on the different uranium ore pulp densities, we analyzed the expression of the four genes from the rus operon by real-time PCR, when Acidithiobacillus sp. FJ2 was grown in the presence of different uranium concentrations. The uranium bioleaching results showed the inhibitory effects of the metal pulp densities on the oxidation activity of the bacteria which can affect Eh, pH, Fe oxidation and uranium extractions. Gene expression analysis indicated that Acidithiobacillus sp. FJ2 tries to survive in the stress with increasing in the expression levels of cyc2, cyc1, rus and coxB, but the metal toxicity has a negative effect on the gene expression in different pulp densities. These results indicated that Acidithiobacillus sp. FJ2 could leach the uranium even in high pulp density (50%) by modulation in rus operon gene responses.
Collapse
Affiliation(s)
- Faezeh Fatemi
- Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
| | - Saba Miri
- Department of Biotechnology, Faculty of Life Science, Alzahra University, Tehran, Iran
| | - Samaneh Jahani
- Department of Microbiology, Faculty of Science, Qom Branch, Islamic Azad University, Qom, Iran
| |
Collapse
|
11
|
Pérez-Henarejos SA, Alcaraz LA, Donaire A. Blue Copper Proteins: A rigid machine for efficient electron transfer, a flexible device for metal uptake. Arch Biochem Biophys 2015; 584:134-48. [DOI: 10.1016/j.abb.2015.08.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 08/24/2015] [Accepted: 08/28/2015] [Indexed: 10/23/2022]
|
12
|
Li TF, Painter RG, Ban B, Blake RC. The Multicenter Aerobic Iron Respiratory Chain of Acidithiobacillus ferrooxidans Functions as an Ensemble with a Single Macroscopic Rate Constant. J Biol Chem 2015; 290:18293-303. [PMID: 26041781 PMCID: PMC4513090 DOI: 10.1074/jbc.m115.657551] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 05/26/2015] [Indexed: 11/06/2022] Open
Abstract
Electron transfer reactions among three prominent colored proteins in intact cells of Acidithiobacillus ferrooxidans were monitored using an integrating cavity absorption meter that permitted the acquisition of accurate absorbance data in suspensions of cells that scattered light. The concentrations of proteins in the periplasmic space were estimated to be 350 and 25 mg/ml for rusticyanin and cytochrome c, respectively; cytochrome a was present as one molecule for every 91 nm(2) in the cytoplasmic membrane. All three proteins were rapidly reduced to the same relative extent when suspensions of live bacteria were mixed with different concentrations of ferrous ions at pH 1.5. The subsequent molecular oxygen-dependent oxidation of the multicenter respiratory chain occurred with a single macroscopic rate constant, regardless of the proteins' in vitro redox potentials or their putative positions in the aerobic iron respiratory chain. The crowded electron transport proteins in the periplasm of the organism constituted an electron conductive medium where the network of protein interactions functioned in a concerted fashion as a single ensemble with a standard reduction potential of 650 mV. The appearance of product ferric ions was correlated with the reduction levels of the periplasmic electron transfer proteins; the limiting first-order catalytic rate constant for aerobic respiration on iron was 7,400 s(-1). The ability to conduct direct spectrophotometric studies under noninvasive physiological conditions represents a new and powerful approach to examine the extent and rates of biological events in situ without disrupting the complexity of the live cellular environment.
Collapse
Affiliation(s)
- Ting-Feng Li
- From the College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana 70125
| | - Richard G Painter
- From the College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana 70125
| | - Bhupal Ban
- From the College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana 70125
| | - Robert C Blake
- From the College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana 70125
| |
Collapse
|
13
|
The Confluence of Heavy Metal Biooxidation and Heavy Metal Resistance: Implications for Bioleaching by Extreme Thermoacidophiles. MINERALS 2015. [DOI: 10.3390/min5030397] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
14
|
Liu J, Chakraborty S, Hosseinzadeh P, Yu Y, Tian S, Petrik I, Bhagi A, Lu Y. Metalloproteins containing cytochrome, iron-sulfur, or copper redox centers. Chem Rev 2014; 114:4366-469. [PMID: 24758379 PMCID: PMC4002152 DOI: 10.1021/cr400479b] [Citation(s) in RCA: 559] [Impact Index Per Article: 55.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Indexed: 02/07/2023]
Affiliation(s)
- Jing Liu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Saumen Chakraborty
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Parisa Hosseinzadeh
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yang Yu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Shiliang Tian
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Igor Petrik
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ambika Bhagi
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yi Lu
- Department of Chemistry, Department of Biochemistry, and Center for Biophysics
and Computational
Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
15
|
Alvarez-Paggi D, Zitare U, Murgida DH. The role of protein dynamics and thermal fluctuations in regulating cytochrome c/cytochrome c oxidase electron transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1196-207. [PMID: 24502917 DOI: 10.1016/j.bbabio.2014.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/22/2014] [Accepted: 01/28/2014] [Indexed: 01/06/2023]
Abstract
In this overview we present recent combined electrochemical, spectroelectrochemical, spectroscopic and computational studies from our group on the electron transfer reactions of cytochrome c and of the primary electron acceptor of cytochrome c oxidase, the CuA site, in biomimetic complexes. Based on these results, we discuss how protein dynamics and thermal fluctuations may impact on protein ET reactions, comment on the possible physiological relevance of these results, and finally propose a regulatory mechanism that may operate in the Cyt/CcO electron transfer reaction in vivo. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
Collapse
Affiliation(s)
- Damian Alvarez-Paggi
- INQUIMAE-CONICET, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, pab. 2, piso 3, C1428EHA Buenos Aires, Argentina
| | - Ulises Zitare
- INQUIMAE-CONICET, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, pab. 2, piso 3, C1428EHA Buenos Aires, Argentina
| | - Daniel H Murgida
- INQUIMAE-CONICET, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, pab. 2, piso 3, C1428EHA Buenos Aires, Argentina.
| |
Collapse
|
16
|
Liu W, Lin J, Pang X, Mi S, Cui S, Lin J. Increases of ferrous iron oxidation activity and arsenic stressed cell growth by overexpression of Cyc2 in Acidithiobacillus ferrooxidans ATCC19859. Biotechnol Appl Biochem 2013; 60:623-8. [PMID: 23980744 DOI: 10.1002/bab.1110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 02/14/2013] [Indexed: 11/07/2022]
Abstract
Acidithiobacillus ferrooxidans plays an important role in bioleaching in reproducing the mineral oxidant of ferric iron (Fe(3+) ) by oxidization of ferrous iron (Fe(2+) ). The high-molecular-weight c-type cytochrome Cyc2 that is located in the external membrane is postulated as the first electron carrier in the Fe(2+) oxidation respiratory pathway of A. ferrooxidans. To increase ferrous iron oxidation activity, a recombinant plasmid pTCYC2 containing cyc2 gene under the control of Ptac promoter was constructed and transferred into A. ferrooxidans ATCC19859. The transcriptional level of cyc2 gene was increased by 2.63-fold and Cyc2 protein expression was observed in the recombinant strain compared with the control. The ferrous iron oxidation activity and the arsenic stressed cell growth of the recombinant strain were also elevated.
Collapse
Affiliation(s)
- Wei Liu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China; Institute of Agro-Food Science and Technology, Shandong Academy of Agricultural Sciences, Jinan, People's Republic of China
| | | | | | | | | | | |
Collapse
|
17
|
Yelton AP, Comolli LR, Justice NB, Castelle C, Denef VJ, Thomas BC, Banfield JF. Comparative genomics in acid mine drainage biofilm communities reveals metabolic and structural differentiation of co-occurring archaea. BMC Genomics 2013; 14:485. [PMID: 23865623 PMCID: PMC3750248 DOI: 10.1186/1471-2164-14-485] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/15/2013] [Indexed: 11/10/2022] Open
Abstract
Background Metal sulfide mineral dissolution during bioleaching and acid mine drainage (AMD) formation creates an environment that is inhospitable to most life. Despite dominance by a small number of bacteria, AMD microbial biofilm communities contain a notable variety of coexisting and closely related Euryarchaea, most of which have defied cultivation efforts. For this reason, we used metagenomics to analyze variation in gene content that may contribute to niche differentiation among co-occurring AMD archaea. Our analyses targeted members of the Thermoplasmatales and related archaea. These results greatly expand genomic information available for this archaeal order. Results We reconstructed near-complete genomes for uncultivated, relatively low abundance organisms A-, E-, and Gplasma, members of Thermoplasmatales order, and for a novel organism, Iplasma. Genomic analyses of these organisms, as well as Ferroplasma type I and II, reveal that all are facultative aerobic heterotrophs with the ability to use many of the same carbon substrates, including methanol. Most of the genomes share genes for toxic metal resistance and surface-layer production. Only Aplasma and Eplasma have a full suite of flagellar genes whereas all but the Ferroplasma spp. have genes for pili production. Cryogenic-electron microscopy (cryo-EM) and tomography (cryo-ET) strengthen these metagenomics-based ultrastructural predictions. Notably, only Aplasma, Gplasma and the Ferroplasma spp. have predicted iron oxidation genes and Eplasma and Iplasma lack most genes for cobalamin, valine, (iso)leucine and histidine synthesis. Conclusion The Thermoplasmatales AMD archaea share a large number of metabolic capabilities. All of the uncultivated organisms studied here (A-, E-, G-, and Iplasma) are metabolically very similar to characterized Ferroplasma spp., differentiating themselves mainly in their genetic capabilities for biosynthesis, motility, and possibly iron oxidation. These results indicate that subtle, but important genomic differences, coupled with unknown differences in gene expression, distinguish these organisms enough to allow for co-existence. Overall this study reveals shared features of organisms from the Thermoplasmatales lineage and provides new insights into the functioning of AMD communities.
Collapse
Affiliation(s)
- Alexis P Yelton
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA
| | | | | | | | | | | | | |
Collapse
|
18
|
Mineral respiration under extreme acidic conditions: from a supramolecular organization to a molecular adaptation in Acidithiobacillus ferrooxidans. Biochem Soc Trans 2012; 40:1324-9. [DOI: 10.1042/bst20120141] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotrophic Gram-negative bacterium that can derive energy from the oxidation of ferrous iron at pH 2 using oxygen as electron acceptor. The study of this bacterium has economic and fundamental biological interest because of its use in the industrial extraction of copper and uranium from ores. For this reason, its respiratory chain has been analysed in detail in recent years. Studies have shown the presence of a functional supercomplex that spans the outer and the inner membranes and allows a direct electron transfer from the extracellular Fe2+ ions to the inner membrane cytochrome c oxidase. Iron induces the expression of two operons encoding proteins implicated in this complex as well as in the regeneration of the reducing power. Most of these are metalloproteins that have been characterized biochemically, structurally and biophysically. For some of them, the molecular basis of their adaptation to the periplasmic acidic environment has been described. Modifications in the metal surroundings have been highlighted for cytochrome c and rusticyanin, whereas, for the cytochrome c oxidase, an additional partner that maintains its stability and activity has been demonstrated recently.
Collapse
|
19
|
Alternative ground states enable pathway switching in biological electron transfer. Proc Natl Acad Sci U S A 2012; 109:17348-53. [PMID: 23054836 DOI: 10.1073/pnas.1204251109] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electron transfer is the simplest chemical reaction and constitutes the basis of a large variety of biological processes, such as photosynthesis and cellular respiration. Nature has evolved specific proteins and cofactors for these functions. The mechanisms optimizing biological electron transfer have been matter of intense debate, such as the role of the protein milieu between donor and acceptor sites. Here we propose a mechanism regulating long-range electron transfer in proteins. Specifically, we report a spectroscopic, electrochemical, and theoretical study on WT and single-mutant Cu(A) redox centers from Thermus thermophilus, which shows that thermal fluctuations may populate two alternative ground-state electronic wave functions optimized for electron entry and exit, respectively, through two different and nearly perpendicular pathways. These findings suggest a unique role for alternative or "invisible" electronic ground states in directional electron transfer. Moreover, it is shown that this energy gap and, therefore, the equilibrium between ground states can be fine-tuned by minor perturbations, suggesting alternative ways through which protein-protein interactions and membrane potential may optimize and regulate electron-proton energy transduction.
Collapse
|
20
|
Ilbert M, Bonnefoy V. Insight into the evolution of the iron oxidation pathways. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:161-75. [PMID: 23044392 DOI: 10.1016/j.bbabio.2012.10.001] [Citation(s) in RCA: 190] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 09/27/2012] [Accepted: 10/01/2012] [Indexed: 01/01/2023]
Abstract
Iron is a ubiquitous element in the universe. Ferrous iron (Fe(II)) was abundant in the primordial ocean until the oxygenation of the Earth's atmosphere led to its widespread oxidation and precipitation. This change of iron bioavailability likely put selective pressure on the evolution of life. This element is essential to most extant life forms and is an important cofactor in many redox-active proteins involved in a number of vital pathways. In addition, iron plays a central role in many environments as an energy source for some microorganisms. This review is focused on Fe(II) oxidation. The fact that the ability to oxidize Fe(II) is widely distributed in Bacteria and Archaea and in a number of quite different biotopes suggests that the dissimilatory Fe(II) oxidation is an ancient energy metabolism. Based on what is known today about Fe(II) oxidation pathways, we propose that they arose independently more than once in evolution and evolved convergently. The iron paleochemistry, the phylogeny, the physiology of the iron oxidizers, and the nature of the cofactors of the redox proteins involved in these pathways suggest a possible scenario for the timescale in which each type of Fe(II) oxidation pathways evolved. The nitrate dependent anoxic iron oxidizers are likely the most ancient iron oxidizers. We suggest that the phototrophic anoxic iron oxidizers arose in surface waters after the Archaea/Bacteria-split but before the Great Oxidation Event. The neutrophilic oxic iron oxidizers possibly appeared in microaerobic marine environments prior to the Great Oxidation Event while the acidophilic ones emerged likely after the advent of atmospheric O(2). This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems.
Collapse
Affiliation(s)
- Marianne Ilbert
- Aix-Marseille Université, CNRS, BIP UMR7281,13009, Marseille, France.
| | | |
Collapse
|
21
|
Folding and unfolding in the blue copper protein rusticyanin: role of the oxidation state. Bioinorg Chem Appl 2011:54232. [PMID: 18354738 PMCID: PMC2267886 DOI: 10.1155/2007/54232] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 05/02/2007] [Accepted: 06/27/2007] [Indexed: 11/17/2022] Open
Abstract
The unfolding process of the blue copper protein rusticyanin has been studied from the structural and the thermodynamic points of view at two pH values (pH 2.5 and 7.0). When Rc unfolds, copper ion remains bound to the polypeptide chain. Nuclear magnetic resonance data suggest that three of the copper ligands in the folded state are bound to the metal ion in the unfolded form, while the other native ligand is detached. These structural changes are reflected in the redox potentials of the protein in both folded and unfolded forms. The affinities of the copper ion in both redox states have been also determined at the two specified pH values. The results indicate that the presence of two histidine ligands in the folded protein can compensate the change in the net charge that the copper ion receives from their ligands, while, in the unfolded protein, charges of aminoacids are completely transferred to the copper ion, altering decisively the relative stability of its two-redox states.
Collapse
|
22
|
Bird LJ, Bonnefoy V, Newman DK. Bioenergetic challenges of microbial iron metabolisms. Trends Microbiol 2011; 19:330-40. [DOI: 10.1016/j.tim.2011.05.001] [Citation(s) in RCA: 264] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 04/30/2011] [Accepted: 05/03/2011] [Indexed: 11/24/2022]
|
23
|
Choi M, Davidson VL. Cupredoxins--a study of how proteins may evolve to use metals for bioenergetic processes. Metallomics 2011; 3:140-51. [PMID: 21258692 DOI: 10.1039/c0mt00061b] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cupredoxins are small proteins that contain type I copper centers, which are ubiquitous in nature. They function as electron transfer shuttles between proteins. This review of the structure and properties of native cupredoxins, and those modified by site-directed mutagenesis, illustrates how these proteins may have evolved to specifically bind copper, develop recognition sites for specific redox partners, tune redox potential for a particular function, and allow for efficient electron transfer through the protein matrix. This is relevant to the general understanding of the roles of metals in energy metabolism, respiration and photosynthesis.
Collapse
Affiliation(s)
- Moonsung Choi
- Department of Biochemistry, University of Mississippi Medical Center, 2500 N. State St., Jackson, MS 39216-4505, USA
| | | |
Collapse
|
24
|
Chang HY, Ahn Y, Pace LA, Lin MT, Lin YH, Gennis RB. The diheme cytochrome c(4) from Vibrio cholerae is a natural electron donor to the respiratory cbb(3) oxygen reductase. Biochemistry 2010; 49:7494-503. [PMID: 20715760 DOI: 10.1021/bi1004574] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The respiratory chain of Vibrio cholerae contains three bd-type quinol oxygen reductases as well as one cbb(3) oxygen reductase. The cbb(3) oxygen reductase has been previously isolated and characterized; however, the natural mobile electron donor(s) that shuttles electrons between the bc(1) complex and the cbb(3) oxygen reductase is not known. The most likely candidates are the diheme cytochrome c(4) and monoheme cytochrome c(5), which have been previously shown to be present in the periplasm of aerobically grown cultures of V. cholerae. Both cytochromes c(4) and c(5) from V. cholerae have been cloned and expressed heterologously in Escherichia coli. It is shown that reduced cytochrome c(4) is a substrate for the purified cbb(3) oxygen reductase and can support steady state oxygen reductase activity of at least 300 e(-1)/s. In contrast, reduced cytochrome c(5) is not a good substrate for the cbb(3) oxygen reductase. Surprisingly, the dependence of the oxygen reductase activity on the concentration of cytochrome c(4) does not exhibit saturation. Global spectroscopic analysis of the time course of the oxidation of cytochrome c(4) indicates that the apparent lack of saturation is due to the strong dependence of K(M) and V(max) on the concentration of oxidized cytochrome c(4). Whether this is an artifact of the in vitro assay or has physiological significance remains unknown. Cyclic voltammetry was used to determine that the midpoint potentials of the two hemes in cytochrome c(4) are 240 and 340 mV (vs standard hydrogen electrode), similar to the electrochemical properties of other c(4)-type cytochromes. Genomic analysis shows a strong correlation between the presence of a c(4)-type cytochrome and a cbb(3) oxygen reductase within the beta- and gamma-proteobacterial clades, suggesting that cytochrome c(4) is the likely natural electron donor to the cbb(3) oxygen reductases within these organisms. These would include the beta-proteobacteria Neisseria meningitidis and Neisseria gonnorhoeae, in which the cbb(3) oxygen reductases are the only terminal oxidases in their respiratory chains, and the gamma-proteobacterium Pseudomonas stutzeri.
Collapse
Affiliation(s)
- Hsin-Yang Chang
- Department of Biochemistry, University of Illinois, Urbana, Illinois 61801, USA
| | | | | | | | | | | |
Collapse
|
25
|
Castelle C, Ilbert M, Infossi P, Leroy G, Giudici-Orticoni MT. An unconventional copper protein required for cytochrome c oxidase respiratory function under extreme acidic conditions. J Biol Chem 2010; 285:21519-25. [PMID: 20442397 PMCID: PMC2898452 DOI: 10.1074/jbc.m110.131359] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 04/30/2010] [Indexed: 11/06/2022] Open
Abstract
Very little is known about the processes used by acidophile organisms to preserve stability and function of respiratory pathways. Here, we reveal a potential strategy of these organisms for protecting and keeping functional key enzymes under extreme conditions. Using Acidithiobacillus ferrooxidans, we have identified a protein belonging to a new cupredoxin subfamily, AcoP, for "acidophile CcO partner," which is required for the cytochrome c oxidase (CcO) function. We show that it is a multifunctional copper protein with at least two roles as follows: (i) as a chaperone-like protein involved in the protection of the Cu(A) center of the CcO complex and (ii) as a linker between the periplasmic cytochrome c and the inner membrane cytochrome c oxidase. It could represent an interesting model for investigating the multifunctionality of proteins known to be crucial in pathways of energy metabolism.
Collapse
Affiliation(s)
- Cindy Castelle
- From the Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM-CNRS, 13402 Marseille Cedex 20, France
| | - Marianne Ilbert
- From the Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM-CNRS, 13402 Marseille Cedex 20, France
| | - Pascale Infossi
- From the Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM-CNRS, 13402 Marseille Cedex 20, France
| | - Gisèle Leroy
- From the Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM-CNRS, 13402 Marseille Cedex 20, France
| | | |
Collapse
|
26
|
Rationally tuning the reduction potential of a single cupredoxin beyond the natural range. Nature 2009; 462:113-6. [PMID: 19890331 DOI: 10.1038/nature08551] [Citation(s) in RCA: 231] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 09/30/2009] [Indexed: 11/08/2022]
Abstract
Redox processes are at the heart of numerous functions in chemistry and biology, from long-range electron transfer in photosynthesis and respiration to catalysis in industrial and fuel cell research. These functions are accomplished in nature by only a limited number of redox-active agents. A long-standing issue in these fields is how redox potentials are fine-tuned over a broad range with little change to the redox-active site or electron-transfer properties. Resolving this issue will not only advance our fundamental understanding of the roles of long-range, non-covalent interactions in redox processes, but also allow for design of redox-active proteins having tailor-made redox potentials for applications such as artificial photosynthetic centres or fuel cell catalysts for energy conversion. Here we show that two important secondary coordination sphere interactions, hydrophobicity and hydrogen-bonding, are capable of tuning the reduction potential of the cupredoxin azurin over a 700 mV range, surpassing the highest and lowest reduction potentials reported for any mononuclear cupredoxin, without perturbing the metal binding site beyond what is typical for the cupredoxin family of proteins. We also demonstrate that the effects of individual structural features are additive and that redox potential tuning of azurin is now predictable across the full range of cupredoxin potentials.
Collapse
|
27
|
Chen H, Yang B, Chen X. Identification and characterization of four strains of Acidithiobacillus ferrooxidans isolated from different sites in China. Microbiol Res 2009; 164:613-23. [DOI: 10.1016/j.micres.2007.09.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 08/26/2007] [Accepted: 09/06/2007] [Indexed: 10/22/2022]
|
28
|
Si D, Li H. Quantum Chemical Calculation of Type-1 Cu Reduction Potential: Ligand Interaction and Solvation Effect. J Phys Chem A 2009; 113:12979-87. [DOI: 10.1021/jp905825q] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dejun Si
- Department of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588
| | - Hui Li
- Department of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588
| |
Collapse
|
29
|
Koteishi H, Nojiri M, Nakagami T, Yamaguchi K, Suzuki S. Cytochromec551Is a Mediator of Electron Transfer between Copper-Containing Nitrite Reductase and Azurin in a Denitrifying Bacterium,Achromobacter xylosoxidans. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2009. [DOI: 10.1246/bcsj.82.1003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
30
|
Kallio JP, Auer S, Jänis J, Andberg M, Kruus K, Rouvinen J, Koivula A, Hakulinen N. Structure-function studies of a Melanocarpus albomyces laccase suggest a pathway for oxidation of phenolic compounds. J Mol Biol 2009; 392:895-909. [PMID: 19563811 DOI: 10.1016/j.jmb.2009.06.053] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 06/11/2009] [Accepted: 06/14/2009] [Indexed: 10/20/2022]
Abstract
Melanocarpus albomyces laccase crystals were soaked with 2,6-dimethoxyphenol, a common laccase substrate. Three complex structures from different soaking times were solved. Crystal structures revealed the binding of the original substrate and adducts formed by enzymatic oxidation of the substrate. The dimeric oxidation products were identified by mass spectrometry. In the crystals, a 2,6-dimethoxy-p-benzoquinone and a C-O dimer were observed, whereas a C-C dimer was the main product identified by mass spectrometry. Crystal structures demonstrated that the substrate and/or its oxidation products were bound in the pocket formed by residues Ala191, Pro192, Glu235, Leu363, Phe371, Trp373, Phe427, Leu429, Trp507 and His508. Substrate and adducts were hydrogen-bonded to His508, one of the ligands of type 1 copper. Therefore, this surface-exposed histidine most likely has a role in electron transfer by laccases. Based on our mutagenesis studies, the carboxylic acid residue Glu235 at the bottom of the binding site pocket is also crucial in the oxidation of phenolics. Glu235 may be responsible for the abstraction of a proton from the OH group of the substrate and His508 may extract an electron. In addition, crystal structures revealed a secondary binding site formed through weak dimerization in M. albomyces laccase molecules. This binding site most likely exists only in crystals, when the Phe427 residues are packed against each other.
Collapse
Affiliation(s)
- J P Kallio
- Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Electron transfer from cytochrome c to cupredoxins. J Biol Inorg Chem 2009; 14:821-8. [DOI: 10.1007/s00775-009-0494-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 02/28/2009] [Indexed: 10/21/2022]
|
32
|
Mukhopadhyay BP, Ghosh B, Bairagya HR, Nandi TK, Chakrabarti B, Bera AK. Molecular Modeling of the Ternary Complex of Rusticyanin-Cytochrome c4-Cytochrome Oxidase: An Insight to Possible H-Bond Mediated Recognition and Electron Transfer Reaction inT.ferrooxidans. J Biomol Struct Dyn 2008; 25:543-51. [DOI: 10.1080/07391102.2008.10507201] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
33
|
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] [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).
Collapse
Affiliation(s)
- B P Mukhopadhyay
- Department of Chemistry, National Institute Of Technology, Durgapur-713209, West Bengal, India.
| | | | | | | | | | | |
Collapse
|
34
|
Battistuzzi G, Bellei M, Dennison C, Di Rocco G, Sato K, Sola M, Yanagisawa S. Thermodynamics of the alkaline transition in phytocyanins. J Biol Inorg Chem 2007; 12:895-900. [PMID: 17569996 DOI: 10.1007/s00775-007-0245-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2007] [Accepted: 04/29/2007] [Indexed: 10/23/2022]
Abstract
The thermodynamics of the alkaline transition which influences the spectral and redox properties of the type 1 copper center in phytocyanins has been determined spectroscopically. The proteins investigated include Rhus vernicifera stellacyanin, cucumber basic protein and its Met89Gln variant, and umecyanin, the stellacyanin from horseradish roots, along with its Gln95Met variant. The changes in reaction enthalpy and entropy within the protein series show partial compensatory behavior. Thus, the reaction free energy change (hence the pK (a) value) is rather variable. This indicates that species-dependent differences in reaction thermodynamics, although containing an important contribution from changes in the hydrogen-bonding network of water molecules in the hydration sphere of the protein (which feature enthalpy-entropy compensation), are to a large extent protein-based. The data for axial ligand variants are consistent with the hypothesis of a copper-binding His as the deprotonating residue responsible for this transition.
Collapse
Affiliation(s)
- Gianantonio Battistuzzi
- Department of Chemistry, University of Modena and Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | | | | | | | | | | | | |
Collapse
|
35
|
Zeng J, Geng M, Liu Y, Xia L, Liu J, Qiu G. The sulfhydryl group of Cys138 of rusticyanin from Acidithiobacillus ferrooxidans is crucial for copper binding. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:519-25. [PMID: 17395555 DOI: 10.1016/j.bbapap.2007.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 02/05/2007] [Accepted: 02/08/2007] [Indexed: 10/23/2022]
Abstract
Rusticyanin is a small blue copper protein isolated from Acidithiobacillus ferrooxidans with extreme acid stability and redox potential. The protein is thought to be a principal component in the iron respiratory electron transport chain in this microorganism, but its exact role in electron transfer remains controversial. The gene of rusticyanin was cloned then overexpressed in Escherichia coli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. It was reported that Cys138, His85 and His143 were important residues for copper binding, but the significance of Cys138 was not verified so far. We constructed the mutant expression plasmids of these three residues using site-directed mutagenesis. Mutant proteins were expressed in E. coli and purified with a nickel metal affinity column. The EPR and atomic absorption spectroscopy results confirmed that Cys138 was crucial for copper binding. Removal of the sulfhydryl group of Cys138 resulted in copper loss. Mutations of His85 and His143 showed little effect on copper binding.
Collapse
Affiliation(s)
- Jia Zeng
- Department of Bioengineering, School of Resources Processing and Bioengineering, Central South University, Changsha, PR China
| | | | | | | | | | | |
Collapse
|
36
|
Williams HD, Zlosnik JEA, Ryall B. Oxygen, cyanide and energy generation in the cystic fibrosis pathogen Pseudomonas aeruginosa. Adv Microb Physiol 2006; 52:1-71. [PMID: 17027370 DOI: 10.1016/s0065-2911(06)52001-6] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pseudomonas aeruginosa is a gram-negative, rod-shaped bacterium that belongs to the gamma-proteobacteria. This clinically challenging, opportunistic pathogen occupies a wide range of niches from an almost ubiquitous environmental presence to causing infections in a wide range of animals and plants. P. aeruginosa is the single most important pathogen of the cystic fibrosis (CF) lung. It causes serious chronic infections following its colonisation of the dehydrated mucus of the CF lung, leading to it being the most important cause of morbidity and mortality in CF sufferers. The recent finding that steep O2 gradients exist across the mucus of the CF-lung indicates that P. aeruginosa will have to show metabolic adaptability to modify its energy metabolism as it moves from a high O2 to low O2 and on to anaerobic environments within the CF lung. Therefore, the starting point of this review is that an understanding of the diverse modes of energy metabolism available to P. aeruginosa and their regulation is important to understanding both its fundamental physiology and the factors significant in its pathogenicity. The main aim of this review is to appraise the current state of knowledge of the energy generating pathways of P. aeruginosa. We first look at the organisation of the aerobic respiratory chains of P. aeruginosa, focusing on the multiple primary dehydrogenases and terminal oxidases that make up the highly branched pathways. Next, we will discuss the denitrification pathways used during anaerobic respiration as well as considering the ability of P. aeruginosa to carry out aerobic denitrification. Attention is then directed to the limited fermentative capacity of P. aeruginosa with discussion of the arginine deiminase pathway and the role of pyruvate fermentation. In the final part of the review, we consider other aspects of the biology of P. aeruginosa that are linked to energy metabolism or affected by oxygen availability. These include cyanide synthesis, which is oxygen-regulated and can affect the operation of aerobic respiratory pathways, and alginate production leading to a mucoid phenotype, which is regulated by oxygen and energy availability, as well as having a role in the protection of P. aeruginosa against reactive oxygen species. Finally, we consider a possible link between cyanide synthesis and the mucoid switch that operates in P. aeruginosa during chronic CF lung infection.
Collapse
Affiliation(s)
- Huw D Williams
- Division of Biology, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ, UK
| | | | | |
Collapse
|
37
|
Impagliazzo A, Blok AJ, Cliff MJ, Ladbury JE, Ubbink M. Redox-State-Dependent Complex Formation between Pseudoazurin and Nitrite Reductase. J Am Chem Soc 2006; 129:226-33. [PMID: 17199303 DOI: 10.1021/ja0659830] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacterial copper-containing nitrite reductase catalyzes the reduction of nitrite to nitric oxide as part of the denitrification process. Pseudoazurin interacts with nitrite reductase in a transient fashion to supply the necessary electrons. The redox-state dependence of complex formation between pseudoazurin and nitrite reductase was studied by nuclear magnetic resonance spectroscopy and isothermal titration calorimetry. Binding of pseudoazurin in the reduced state is characterized by the presence of two binding modes, a slow and a fast exchange mode, with a K(d)(app) of 100 microM. In the oxidized state of pseudoazurin, binding occurs in a single fast exchange mode with a similar affinity. Metal-substituted proteins have been used to show that the mode of binding of pseudoazurin is independent of the metal charge of nitrite reductase. Contrary to what was found for other cupredoxins, protonation of the exposed His ligand to the copper of pseudoazurin, His81, does not appear to be involved directly in the dual binding mode of the reduced form. A model assuming the presence of a minor form of pseudoazurin is proposed to explain the behavior of the complex in the reduced state.
Collapse
Affiliation(s)
- Antonietta Impagliazzo
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | | | | | | | | |
Collapse
|
38
|
Nouailler M, Bruscella P, Lojou E, Lebrun R, Bonnefoy V, Guerlesquin F. Structural analysis of the HiPIP from the acidophilic bacteria: Acidithiobacillus ferrooxidans. Extremophiles 2006; 10:191-8. [PMID: 16604275 DOI: 10.1007/s00792-005-0486-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Accepted: 10/02/2005] [Indexed: 10/24/2022]
Abstract
Hip is a high-potential iron-sulfur protein (HiPIP) isolated from the acidophilic bacterium, Acidithiobacillus ferrooxidans. In the present work, a structural model of Hip suggests that the role of proline residues is essential to stabilize the protein folding at very low pH. The presence of an unusual disulfide bridge in Hip is demonstrated using mass spectrometry and nuclear magnetic resonance. This disulfide bridge is necessary to anchor the N-terminal extremity of the protein, but is not involved in the acid stability of Hip. The structural parameters correlated with the pH dependence of Hip redox potential are also analysed on the basis of this model. Given that the same structural features can enhance acidic stability and lead to elevated redox potentials, modulation of the redox potentials of electron carriers may be necessary to achieve electron transfer at very low pH.
Collapse
Affiliation(s)
- Matthieu Nouailler
- Unité de Bioénergétique et Ingénierie des Protéines, CNRS, 31 chemin Joseph Aiguier, 13402 Marseille, Cedex 20, France
| | | | | | | | | | | |
Collapse
|
39
|
Chen Y, Suzuki I. Effects of electron transport inhibitors and uncouplers on the oxidation of ferrous iron and compounds interacting with ferric iron in Acidithiobacillus ferrooxidans. Can J Microbiol 2006; 51:695-703. [PMID: 16234867 DOI: 10.1139/w05-051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxidation of Fe2+, ascorbic acid, propyl gallate, tiron, L-cysteine, and glutathione by Acidithiobacillus ferrooxidans was studied with respect to the effect of electron transport inhibitors and uncouplers on the rate of oxidation. All the oxidations were sensitive to inhibitors of cytochrome c oxidase, KCN, and NaN3. They were also partially inhibited by inhibitors of complex I and complex III of the electron transport system. Uncouplers at low concentrations stimulated the oxidation and inhibited it at higher concentrations. The oxidation rates of Fe2+ and L-cysteine inhibited by complex I and complex III inhibitors (amytal, rotenone, antimycin A, myxothiazol, and HQNO) were stimulated more extensively by uncouplers than the control rates. Atabrine, a flavin antagonist, was an exception, and atabrine-inhibited oxidation activities of all these compounds were further inhibited by uncouplers. A model for the electron transport pathways of A. ferrooxidans is proposed to account for these results. In the model these organic substrates reduce ferric iron on the surface of cells to ferrous iron, which is oxidized back to ferric iron through the Fe2+ oxidation pathway, leading to cytochrome oxidase to O2. Some of electrons enter the uphill (energy-requiring) electron transport pathway to reduce NAD+. Uncouplers at low concentrations stimulate Fe2+ oxidation by stimulating cytochrome oxidase by uncoupling. Higher concentrations lower deltap to the level insufficient to overcome the potentially uphill reaction at rusticyanin-cytochrome c4. Inhibition of uphill reactions at complex I and complex III leads to deltap accumulation and inhibition of cytochrome oxidase. Uncouplers remove the inhibition of deltap and stimulate the oxidation. Atabrine inhibition is not released by uncouplers, which implies a possibility of atabrine inhibition at a site other than complex I, but a site somehow involved in the Fe2+ oxidation pathway.
Collapse
Affiliation(s)
- Yongqiang Chen
- Department of Microbiology, University of Manitoba, Winnipeg, Canada.
| | | |
Collapse
|
40
|
|
41
|
Delfino I, Sato K, Harrison MD, Andolfi L, Bizzarri AR, Dennison C, Cannistraro S. Optical Spectroscopic Investigation of the Alkaline Transition in Umecyanin from Horseradish Root†. Biochemistry 2005; 44:16090-7. [PMID: 16331969 DOI: 10.1021/bi051702+] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Umecyanin (UMC) from horseradish root belongs to the stellacyanin subclass of the phytocyanins, a family of plant cupredoxins. The protein possesses the typical type-1 His(2)Cys equatorial ligand set at its mononuclear copper site but has an axial Gln ligand in place of the usual weakly coordinated Met of the plantacyanins, uclacyanins, and most other cupredoxins. UMC exhibits, like other phytocyanins, altered visible, EPR, and paramagnetic (1)H NMR spectra at elevated pH values and also a modified reduction potential. This alkaline transition occurs with a pK(a) of approximately 10 [Dennison, C., Lawler, A. T. (2001) Biochemistry 40, 3158-3166]. In this study, we investigate the alkaline transition by complementary optical spectroscopic techniques. The contemporary use of absorption, fluorescence, dynamic light scattering, and resonance Raman spectroscopy allows us to demonstrate that the alkaline transition induces a reorganization of the protein and that the overall size of UMC increases, but protein aggregation does not occur. The transition does not have a dramatic influence on the active-site environment of UMC, but there are subtle alterations in the Cu site geometry. Direct evidence for the strengthening of a Cu-N(His) bond is presented, which is in agreement with the hypothesis that the deprotonation of the N(epsilon2)H moiety of one of the His ligands is the cause of the alkaline transition. A weakening of the Cu-S(Cys) bond is also observed which, along with a weakened axial interaction, must be due to the enhanced Cu-N(His) interaction.
Collapse
Affiliation(s)
- Ines Delfino
- Biophysics and Nanoscience Centre, INFM-CNISM, Dipartimento Scienze Ambientali, Università della Tuscia, Largo dell'Università, I-01100 Viterbo, Italy
| | | | | | | | | | | | | |
Collapse
|
42
|
Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
| | | | | |
Collapse
|
43
|
Malarte G, Leroy G, Lojou E, Abergel C, Bruschi M, Giudici-Orticoni MT. Insight into Molecular Stability and Physiological Properties of the Diheme Cytochrome CYC41 from the Acidophilic Bacterium Acidithiobacillus ferrooxidans. Biochemistry 2005; 44:6471-81. [PMID: 15850381 DOI: 10.1021/bi048425b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cyc1 gene encoding the soluble dihemic cytochrome c CYC(41) from Acidithiobacillus ferrooxidans, an acidophilic organism, has been cloned and expressed in Escherichia coli as the host organism. The cytochrome was successfully produced and folded only in fermentative conditions: this allowed us to determine the molecular basis of the heme insertion at extreme pH. Point mutations at two sequence positions (E121 and Y63) were introduced near the two hemes in order to assign individual redox potentials to the hemes and to identify the interaction sites with the redox partners, rusticyanin and cytochrome oxidase. Characterization of mutants E121A, Y63A, and Y63F CYC(41) with biochemical and biophysical techniques were carried out. Substitution of tyrosine 63 by phenylalanine alters the environment of heme B. This result indicates that heme B has the lower redox potential. Interaction studies with the two physiological partners indicate that CYC(41) functions as an electron wire between RCy and cytochrome oxidase. A specific glutamate residue (E121) located near heme A is directly involved in the interaction with RCy. A docking analysis of CYC(41), RCy, and cytochrome oxidase allowed us to propose a model for the complex in agreement with our experimental data.
Collapse
Affiliation(s)
- Guillaume Malarte
- Bioénergétique et Ingénierie des Protéines, CNRS, IBSM, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | | | | | | | | | | |
Collapse
|
44
|
Harrison MD, Yanagisawa S, Dennison C. Investigating the Cause of the Alkaline Transition of Phytocyanins. Biochemistry 2005; 44:3056-64. [PMID: 15723550 DOI: 10.1021/bi048256v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The phytocyanins are a family of plant cupredoxins that have been subdivided into the stellacyanins, plantacyanins, and uclacyanins. All of these proteins possess the typical type 1 His(2)Cys equatorial ligand set at their mononuclear copper sites, but the stellacyanins have an axial Gln ligand in place of the weakly coordinated Met of the plantacyanins, uclacyanins, and most other cupredoxins. The stellacyanins exhibit altered visible, EPR, and paramagnetic (1)H NMR spectra at elevated pH values and also modified reduction potentials. This alkaline transition occurs with a pK(a) of approximately 10 [Dennison, C., Lawler, A. T. (2001) Biochemistry 40, 3158-3166]. In this study we demonstrate that the alkaline transition has a similar influence on the visible, EPR, and paramagnetic NMR spectra of cucumber basic protein (CBP), which is a plantacyanin. The mutation of the axial Gln95 ligand into a Met in umecyanin (UMC), the stellacyanin from horseradish roots, and the axial Met89 into a Gln in CBP have very limited, yet similar, influence on the pK(a) for the alkaline transition as judged from alterations in visible spectra. The complete removal of the axial ligand in the Met89Val variant of CBP results in a slightly larger decrease in the pK(a) for this effect, but similar spectral alterations are still observed at elevated pH. Thus, the axial Gln ligand is not the cause of the alkaline transition in Cu(II) stellacyanins, and alterations in the active site structures of the phytocyanins have a limited effect on this feature. The conserved Lys residue found adjacent to the axial ligand in the sequences of all phytocyanins, and implicated as the trigger for the alkaline transition, has been mutated to an Arg in UMC. The influence of increasing pH on the spectroscopic properties of Lys96Arg UMC is almost identical to those of the wild type protein, and thus, this residue is not responsible for the alkaline transition. However, a positively charged residue in this position seems to be important for the correct folding of UMC. Other possible triggers for the effects seen in the phytocyanins at elevated pH are discussed along with the relevance of the alkaline transition.
Collapse
Affiliation(s)
- Mark D Harrison
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH, UK
| | | | | |
Collapse
|
45
|
Chen Y, Suzuki I. Effect of uncouplers on endogenous respiration and ferrous iron oxidation in a chemolithoautotrophic bacteriumAcidithiobacillus(Thiobacillus)ferrooxidans. FEMS Microbiol Lett 2004. [DOI: 10.1111/j.1574-6968.2004.tb09689.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
46
|
Brasseur G, Levican G, Bonnefoy V, Holmes D, Jedlicki E, Lemesle-Meunier D. Apparent redundancy of electron transfer pathways via bc(1) complexes and terminal oxidases in the extremophilic chemolithoautotrophic Acidithiobacillus ferrooxidans. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2004; 1656:114-26. [PMID: 15178473 DOI: 10.1016/j.bbabio.2004.02.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Revised: 02/16/2004] [Accepted: 02/16/2004] [Indexed: 11/19/2022]
Abstract
Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotrophic bacterium that can grow in the presence of either the weak reductant Fe(2+), or reducing sulfur compounds that provide more energy for growth than Fe(2+). We have previously shown that the uphill electron transfer pathway between Fe(2+) and NAD(+) involved a bc(1) complex that functions only in the reverse direction [J. Bacteriol. 182, (2000) 3602]. In the present work, we demonstrate both the existence of a bc(1) complex functioning in the forward direction, expressed when the cells are grown on sulfur, and the presence of two terminal oxidases, a bd and a ba(3) type oxidase expressed more in sulfur than in iron-grown cells, besides the cytochrome aa(3) that was found to be expressed only in iron-grown cells. Sulfur-grown cells exhibit a branching point for electron flow at the level of the quinol pool leading on the one hand to a bd type oxidase, and on the other hand to a bc(1)-->ba(3) pathway. We have also demonstrated the presence in the genome of transcriptionally active genes potentially encoding the subunits of a bo(3) type oxidase. A scheme for the electron transfer chains has been established that shows the existence of multiple respiratory routes to a single electron acceptor O(2). Possible reasons for these apparently redundant pathways are discussed.
Collapse
Affiliation(s)
- G Brasseur
- Laboratoire de Bioénergétique et Ingénierie des Protéines, IBSM, CNRS, 31 Chemin J. Aiguier 13402 Marseille Cedex 20, France
| | | | | | | | | | | |
Collapse
|
47
|
Yarzábal A, Appia-Ayme C, Ratouchniak J, Bonnefoy V. Regulation of the expression of the Acidithiobacillus ferrooxidans rus operon encoding two cytochromes c, a cytochrome oxidase and rusticyanin. Microbiology (Reading) 2004; 150:2113-2123. [PMID: 15256554 DOI: 10.1099/mic.0.26966-0] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The regulation of the expression of the rus operon, proposed to encode an electron transfer chain from the outer to the inner membrane in the obligate acidophilic chemolithoautroph Acidithiobacillus ferrooxidans, has been studied at the RNA and protein levels. As observed by Northern hybridization, real-time PCR and reverse transcription analyses, this operon was more highly expressed in ferrous iron- than in sulfur-grown cells. Furthermore, it was shown by immunodetection that components of this respiratory chain are synthesized in ferrous iron- rather than in sulfur-growth conditions. Nonetheless, weak transcription and translation products of the rus operon were detected in sulfur-grown cells at the early exponential phase. The results strongly support the notion that rus-operon expression is induced by ferrous iron, in agreement with the involvement of the rus-operon-encoded products in the oxidation of ferrous iron, and that ferrous iron is used in preference to sulfur.
Collapse
Affiliation(s)
- Andrés Yarzábal
- Laboratorio de Organización y Expresión del Gen, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Corinne Appia-Ayme
- Laboratoire de Chimie Bactérienne, CNRS, IBSM, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Jeanine Ratouchniak
- Laboratoire de Chimie Bactérienne, CNRS, IBSM, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Violaine Bonnefoy
- Laboratoire de Chimie Bactérienne, CNRS, IBSM, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| |
Collapse
|
48
|
Abergel C, Nitschke W, Malarte G, Bruschi M, Claverie JM, Giudici-Orticoni MT. The structure of Acidithiobacillus ferrooxidans c(4)-cytochrome: a model for complex-induced electron transfer tuning. Structure 2003; 11:547-55. [PMID: 12737820 DOI: 10.1016/s0969-2126(03)00072-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The study of electron transfer between the copper protein rusticyanin (RCy) and the c(4)-cytochrome CYC(41) of the acidophilic bacterium Acidithiobacillus ferrooxidans has evidenced a remarkable decrease of RCy's redox potential upon complex formation. The structure of the CYC(41) obtained at 2.2 A resolution highlighted a specific glutamate residue (E121) involved in zinc binding as potentially playing a central role in this effect, required for the electron transfer to occur. EPR and stopped-flow experiments confirmed the strong inhibitory effect of divalent cations on CYC(41):RCy complex formation. A docking analysis of the CYC(41) and RCy structure allows us to propose a detailed model for the complex-induced tuning of electron transfer in agreement with our experimental data, which could be representative of other copper proteins involved in electron transfer.
Collapse
Affiliation(s)
- Chantal Abergel
- Information Génomique et Structurale, UPR 2589, Institut de Biologie Structurale et Microbiologie, 31 Chemin Joseph Aiguier, 13402 20, Marseille cedex, France.
| | | | | | | | | | | |
Collapse
|
49
|
Sasaki K, Ida C, Ando A, Matsumoto N, Saiki H, Ohmura N. Respiratory isozyme, two types of rusticyanin of Acidithiobacillus ferrooxidans. Biosci Biotechnol Biochem 2003; 67:1039-47. [PMID: 12834281 DOI: 10.1271/bbb.67.1039] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Among the members of the copper protein superfamily, the type I enzyme rusticyanin, which is found as an electron carrier in the oxidative respiratory chain of Acidithiobacillus ferrooxidans, is the only one to have both a high redox potential and acid stability. Here we report that two forms of the rusticyanin gene (rus) are present in the genomes of some strains of A. ferrooxidans. The more common form of rus (type-A) was found to be present in all six strains studied, including those harboring only a single copy of the gene. In addition a less common form (type-B) occurred in strains harboring multiple copies of the gene. The two genes were expressed as rusticyanin isozymes with differing surface charges due to differences in their amino acid composition. Still, the copper coordination sites were completely conserved, thereby maintaining the high redox potential necessary for an electron carrier.
Collapse
Affiliation(s)
- Kazuhiro Sasaki
- Central Research Institute of Electric Power Industry, Department of Bio-science, 1646 Abiko, Abiko City, Chiba 270-1194, Japan
| | | | | | | | | | | |
Collapse
|
50
|
Affiliation(s)
- Aram M Nersissian
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, USA
| | | |
Collapse
|