1
|
Esser L, Xia D. Mitochondrial Cytochrome bc1 Complex as Validated Drug Target: A Structural Perspective. Trop Med Infect Dis 2024; 9:39. [PMID: 38393128 PMCID: PMC10892539 DOI: 10.3390/tropicalmed9020039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
Mitochondrial respiratory chain Complex III, also known as cytochrome bc1 complex or cyt bc1, is a validated target not only for antibiotics but also for pesticides and anti-parasitic drugs. Although significant progress has been made in understanding the mechanisms of cyt bc1 function and inhibition by using various natural and synthetic compounds, important issues remain in overcoming drug resistance in agriculture and in evading cytotoxicity in medicine. In this review, we look at these issues from a structural perspective. After a brief description of the essential and common structural features, we point out the differences among various cyt bc1 complexes of different organisms, whose structures have been determined to atomic resolution. We use a few examples of cyt bc1 structures determined via bound inhibitors to illustrate both conformational changes observed and implications to the Q-cycle mechanism of cyt bc1 function. These structures not only offer views of atomic interactions between cyt bc1 complexes and inhibitors, but they also provide explanations for drug resistance when structural details are coupled to sequence changes. Examples are provided for exploiting structural differences in evolutionarily conserved enzymes to develop antifungal drugs for selectivity enhancement, which offer a unique perspective on differential interactions that can be exploited to overcome cytotoxicity in treating human infections.
Collapse
Affiliation(s)
| | - Di Xia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Room 2122C, Bethesda, MD 20892, USA
| |
Collapse
|
2
|
Havens J, Su T, Wang Q, Yu CA, Yu L, Durham B, Millett F. Photoinduced electron transfer in cytochrome bc 1: Dynamics of rotation of the Iron-sulfur protein during bifurcated electron transfer from ubiquinol to cytochrome c 1 and cytochrome b L. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148957. [PMID: 36709837 DOI: 10.1016/j.bbabio.2023.148957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 01/12/2023] [Accepted: 01/20/2023] [Indexed: 01/27/2023]
Abstract
The electron transfer reactions within wild-type Rhodobacter sphaeroides cytochrome bc1 (cyt bc1) were studied using a binuclear ruthenium complex to rapidly photooxidize cyt c1. When cyt c1, the iron‑sulfur center Fe2S2, and cyt bH were reduced before the reaction, photooxidation of cyt c1 led to electron transfer from Fe2S2 to cyt c1 with a rate constant of ka = 80,000 s-1, followed by bifurcated reduction of both Fe2S2 and cyt bL by QH2 in the Qo site with a rate constant of k2 = 3000 s-1. The resulting Q then traveled from the Qo site to the Qi site and oxidized one equivalent each of cyt bL and cyt bH with a rate constant of k3 = 340 s-1. The rate constant ka was decreased in a nonlinear fashion by a factor of 53 as the viscosity was increased to 13.7. A mechanism that is consistent with the effect of viscosity involves rotational diffusion of the iron‑sulfur protein from the b state with reduced Fe2S2 close to cyt bL to one or more intermediate states, followed by rotation to the final c1 state with Fe2S2 close to cyt c1, and rapid electron transfer to cyt c1.
Collapse
Affiliation(s)
- Jeffrey Havens
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States of America; Vaccines and Therapeutics Division, Chemical and Biological Technologies, Defense Threat Reduction Agency, Fort Belvoir, VA 22060, United States of America
| | - Ting Su
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, United States of America; ABclonal Technology Woburn, MA 01801, United States of America
| | - Qiyu Wang
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, United States of America; Vesigen Therapeutics Cambridge, MA 02139, United States of America
| | - Chang-An Yu
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, United States of America
| | - Linda Yu
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, United States of America
| | - Bill Durham
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States of America
| | - Francis Millett
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States of America.
| |
Collapse
|
3
|
Vercellino I, Sazanov LA. The assembly, regulation and function of the mitochondrial respiratory chain. Nat Rev Mol Cell Biol 2022; 23:141-161. [PMID: 34621061 DOI: 10.1038/s41580-021-00415-0] [Citation(s) in RCA: 268] [Impact Index Per Article: 134.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2021] [Indexed: 02/08/2023]
Abstract
The mitochondrial oxidative phosphorylation system is central to cellular metabolism. It comprises five enzymatic complexes and two mobile electron carriers that work in a mitochondrial respiratory chain. By coupling the oxidation of reducing equivalents coming into mitochondria to the generation and subsequent dissipation of a proton gradient across the inner mitochondrial membrane, this electron transport chain drives the production of ATP, which is then used as a primary energy carrier in virtually all cellular processes. Minimal perturbations of the respiratory chain activity are linked to diseases; therefore, it is necessary to understand how these complexes are assembled and regulated and how they function. In this Review, we outline the latest assembly models for each individual complex, and we also highlight the recent discoveries indicating that the formation of larger assemblies, known as respiratory supercomplexes, originates from the association of the intermediates of individual complexes. We then discuss how recent cryo-electron microscopy structures have been key to answering open questions on the function of the electron transport chain in mitochondrial respiration and how supercomplexes and other factors, including metabolites, can regulate the activity of the single complexes. When relevant, we discuss how these mechanisms contribute to physiology and outline their deregulation in human diseases.
Collapse
Affiliation(s)
- Irene Vercellino
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
| |
Collapse
|
4
|
Xin JW, Chai ZX, Zhang CF, Yang YM, Zhang Q, Zhu Y, Cao HW, YangJi C, Zhong JC, Ji QM. Comparative Analysis of Skeleton Muscle Proteome Profile between Yak and Cattle Provides Insight into High-Altitude Adaptation. CURR PROTEOMICS 2021. [DOI: 10.2174/1570164617666200127151931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background::
Mechanisms underlying yak adaptation to high-altitude environments have
been investigated at the levels of morphology, anatomy, physiology, genome and transcriptome, but
have not been explored at the proteome level.
Objective:
The protein profiles were compared between yak and cattle to explore molecular mechanisms
underlying yak adaptation to high altitude conditions.
Methods:
In the present study, an antibody microarray chip was developed, which included 6,500
mouse monoclonal antibodies. Immunoprecipitation and mass spectrometry were performed on 12
selected antibodies which showed that the chip was highly specific. Using this chip, muscle tissue proteome
was compared between yak and cattle, and 12 significantly Differentially Expressed Proteins (DEPs)
between yak and cattle were identified. Their expression levels were validated using Western blot.
Results:
ompared with cattle, higher levels of Rieske Iron-Sulfur Protein (RISP), Cytochrome C oxidase
subunit 4 isoform 1, mitochondrial (COX4I1), ATP synthase F1 subunit beta (ATP5F1B), Sarcoplasmic/
Endoplasmic Reticulum Calcium ATPase1 (SERCA1) and Adenosine Monophosphate Deaminase1
(AMPD1) in yak might improve oxygen utilization and energy metabolism. Pyruvate Dehydrogenase
protein X component (PDHX) and Acetyltransferase component of pyruvate dehydrogenase
complex (DLAT) showed higher expression levels and L-lactate dehydrogenase A chain (LDHA)
showed lower expression level in yak, which might help yak reduce the accumulation of lactic acid. In
addition, higher expression levels of Filamin C (FLNC) and low levels of AHNAK and Four and a half
LIM domains 1 (FHL1) in yak might reduce the risks of pulmonary arteries vasoconstriction, remodeling
and hypertension.
Conclusion:
Overall, the present study reported the differences in protein profile between yak and cattle,
which might be helpful to further understand molecular mechanisms underlying yak adaptation to
high altitude environments.
Collapse
Affiliation(s)
- Jin-Wei Xin
- State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, China
| | - Zhi-Xin Chai
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Sichuan Province and Ministry of Education, Southwest Minzu University, Chengdu, China
| | - Cheng-Fu Zhang
- State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, China
| | - Yu-Mei Yang
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Sichuan Province and Ministry of Education, Southwest Minzu University, Chengdu, China
| | - Qiang Zhang
- State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, China
| | - Yong Zhu
- State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, China
| | - Han-Wen Cao
- State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, China
| | - Cidan YangJi
- State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, China
| | - Jin-Cheng Zhong
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Sichuan Province and Ministry of Education, Southwest Minzu University, Chengdu, China
| | - Qiu-Mei Ji
- State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, China
| |
Collapse
|
5
|
Malone LA, Proctor MS, Hitchcock A, Hunter CN, Johnson MP. Cytochrome b 6f - Orchestrator of photosynthetic electron transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148380. [PMID: 33460588 DOI: 10.1016/j.bbabio.2021.148380] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 11/18/2022]
Abstract
Cytochrome b6f (cytb6f) lies at the heart of the light-dependent reactions of oxygenic photosynthesis, where it serves as a link between photosystem II (PSII) and photosystem I (PSI) through the oxidation and reduction of the electron carriers plastoquinol (PQH2) and plastocyanin (Pc). A mechanism of electron bifurcation, known as the Q-cycle, couples electron transfer to the generation of a transmembrane proton gradient for ATP synthesis. Cytb6f catalyses the rate-limiting step in linear electron transfer (LET), is pivotal for cyclic electron transfer (CET) and plays a key role as a redox-sensing hub involved in the regulation of light-harvesting, electron transfer and photosynthetic gene expression. Together, these characteristics make cytb6f a judicious target for genetic manipulation to enhance photosynthetic yield, a strategy which already shows promise. In this review we will outline the structure and function of cytb6f with a particular focus on new insights provided by the recent high-resolution map of the complex from Spinach.
Collapse
Affiliation(s)
- Lorna A Malone
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew S Proctor
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
| |
Collapse
|
6
|
Melin F, Hellwig P. Redox Properties of the Membrane Proteins from the Respiratory Chain. Chem Rev 2020; 120:10244-10297. [DOI: 10.1021/acs.chemrev.0c00249] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Frederic Melin
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
| | - Petra Hellwig
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
| |
Collapse
|
7
|
Cheng H, Yang L, Liu HF, Zhang R, Chen C, Wu Y, Jiang W. N-(4-(2-chloro-4-(trifluoromethyl)phenoxy)phenyl)picolinamide as a new inhibitor of mitochondrial complex III: Synthesis, biological evaluation and computational simulations. Bioorg Med Chem Lett 2020; 30:127302. [DOI: 10.1016/j.bmcl.2020.127302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/15/2020] [Accepted: 05/31/2020] [Indexed: 01/23/2023]
|
8
|
Xiong MQ, Chen T, Wang YX, Zhu XL, Yang GF. Design and synthesis of potent inhibitors of bc 1 complex based on natural product neopeltolide. Bioorg Med Chem Lett 2020; 30:127324. [PMID: 32631529 DOI: 10.1016/j.bmcl.2020.127324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/03/2020] [Accepted: 06/03/2020] [Indexed: 10/24/2022]
Abstract
Neopeltolide, a natural product isolated from deep-water sponge specimen of the family neopeltidae, has been proven to be a novel inhibitor of cytochrome bc1. In this study, a series of neopeltolide derivatives was designed by replacing the 14-membered macrolactone with indole ring and confirmed by 1H NMR, 13C NMR, and HRMS. Based on the binding mode of 12h with bc1 complex, the IC50 values of compounds 16a-f (ranging from 0.70 to 1.46 μM) were improved significantly than the ester derivatives 12a-u by replacing the ester with amide linker. Subsequently, the molecular docking results indicated that compound 16e could form a π-π interaction with Phe274 and two H-bonds with Glu271 and His161 and the latter H-bond was found to account for its high activity. The present work accelerates the discovery of novel bc1 complex inhibitors to deal with the resistance that the existing bc1 complex inhibitors are facing and provides a valuable idea for the design of new fungicides.
Collapse
Affiliation(s)
- Mao-Qian Xiong
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health, College of Chemistry, Chemical Biology Center, Central China Normal University, Wuhan 430079, PR China
| | - Tao Chen
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health, College of Chemistry, Chemical Biology Center, Central China Normal University, Wuhan 430079, PR China
| | - Yu-Xia Wang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health, College of Chemistry, Chemical Biology Center, Central China Normal University, Wuhan 430079, PR China
| | - Xiao-Lei Zhu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health, College of Chemistry, Chemical Biology Center, Central China Normal University, Wuhan 430079, PR China.
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health, College of Chemistry, Chemical Biology Center, Central China Normal University, Wuhan 430079, PR China; Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300071, PR China.
| |
Collapse
|
9
|
Cheng H, Liu HF, Yang L, Zhang R, Chen C, Wu Y, Jiang W. N-(3,5-Dichloro-4-(2,4,6-trichlorophenoxy)phenyl)benzenesulfonamide: A new dual-target inhibitor of mitochondrial complex II and complex III via structural simplification. Bioorg Med Chem 2020; 28:115299. [DOI: 10.1016/j.bmc.2019.115299] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 12/19/2019] [Accepted: 12/26/2019] [Indexed: 12/22/2022]
|
10
|
Zhu XL, Zhang R, Wu QY, Song YJ, Wang YX, Yang JF, Yang GF. Natural Product Neopeltolide as a Cytochrome bc 1 Complex Inhibitor: Mechanism of Action and Structural Modification. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:2774-2781. [PMID: 30794394 DOI: 10.1021/acs.jafc.8b06195] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The marine natural product neopeltolide was isolated from a deep-water sponge specimen of the family Neopeltidae. Neopeltolide has been proven to be a new type of inhibitor of the cytochrome bc1 complex in the mitochondrial respiration chain. However, its detailed inhibition mechanism has remained unknown. In addition, neopeltolide is difficult to synthesize because of its very complex chemical structure. In the present work, the binding mode of neopeltolide was determined for the first time by integrating molecular docking, molecular dynamics simulations, and molecular mechanics Poisson-Boltzmann surface area calculations, which showed that neopeltolide is a Qo site inhibitor of the bc1 complex. Then, according to guidance via inhibitor-protein interaction analysis, structural modification was carried out with the aim to simplify the chemical structure of neopeltolide, leading to the synthesis of a series of new neopeltolide derivatives with much simpler chemical structures. The calculated binding energies (Δ Gcal) of the newly synthesized analogues correlated very well ( R2 = 0.90) with their experimental binding free energies (Δ Gexp), which confirmed that the computational protocol was reliable. Compound 45, bearing a diphenyl ether fragment, was successfully designed and synthesized as the most potent candidate (IC50 = 12 nM) against porcine succinate cytochrome c reductase. The molecular modeling results indicate that compound 45 formed a π-π interaction with Phe274 and two hydrogen bonds with Glu271 and His161. The present work provides a new starting point for future fungicide discovery to overcome the resistance that the existing bc1 complex inhibitors are facing.
Collapse
Affiliation(s)
- Xiao-Lei Zhu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health of Ministry of Science and Technology , Central China Normal University , Wuhan , Hubei 430079 , People's Republic of China
| | - Rui Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health of Ministry of Science and Technology , Central China Normal University , Wuhan , Hubei 430079 , People's Republic of China
| | - Qiong-You Wu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health of Ministry of Science and Technology , Central China Normal University , Wuhan , Hubei 430079 , People's Republic of China
| | - Yong-Jun Song
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health of Ministry of Science and Technology , Central China Normal University , Wuhan , Hubei 430079 , People's Republic of China
| | - Yu-Xia Wang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health of Ministry of Science and Technology , Central China Normal University , Wuhan , Hubei 430079 , People's Republic of China
| | - Jing-Fang Yang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health of Ministry of Science and Technology , Central China Normal University , Wuhan , Hubei 430079 , People's Republic of China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, International Joint Research Center for Intelligent Biosensor Technology and Health of Ministry of Science and Technology , Central China Normal University , Wuhan , Hubei 430079 , People's Republic of China
- Collaborative Innovation Center of Chemical Science and Engineering , Tianjin 300071 , People's Republic of China
| |
Collapse
|
11
|
Synthesis, biochemical evaluation and computational simulations of new cytochrome bc1 complex inhibitors based on N-(4-aryloxyphenyl) phthalimides. CHINESE CHEM LETT 2018. [DOI: 10.1016/j.cclet.2018.10.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
|
12
|
Yung YL, Chen P, Nealson K, Atreya S, Beckett P, Blank JG, Ehlmann B, Eiler J, Etiope G, Ferry JG, Forget F, Gao P, Hu R, Kleinböhl A, Klusman R, Lefèvre F, Miller C, Mischna M, Mumma M, Newman S, Oehler D, Okumura M, Oremland R, Orphan V, Popa R, Russell M, Shen L, Sherwood Lollar B, Staehle R, Stamenković V, Stolper D, Templeton A, Vandaele AC, Viscardy S, Webster CR, Wennberg PO, Wong ML, Worden J. Methane on Mars and Habitability: Challenges and Responses. ASTROBIOLOGY 2018; 18:1221-1242. [PMID: 30234380 PMCID: PMC6205098 DOI: 10.1089/ast.2018.1917] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 06/12/2018] [Indexed: 05/05/2023]
Abstract
Recent measurements of methane (CH4) by the Mars Science Laboratory (MSL) now confront us with robust data that demand interpretation. Thus far, the MSL data have revealed a baseline level of CH4 (∼0.4 parts per billion by volume [ppbv]), with seasonal variations, as well as greatly enhanced spikes of CH4 with peak abundances of ∼7 ppbv. What do these CH4 revelations with drastically different abundances and temporal signatures represent in terms of interior geochemical processes, or is martian CH4 a biosignature? Discerning how CH4 generation occurs on Mars may shed light on the potential habitability of Mars. There is no evidence of life on the surface of Mars today, but microbes might reside beneath the surface. In this case, the carbon flux represented by CH4 would serve as a link between a putative subterranean biosphere on Mars and what we can measure above the surface. Alternatively, CH4 records modern geochemical activity. Here we ask the fundamental question: how active is Mars, geochemically and/or biologically? In this article, we examine geological, geochemical, and biogeochemical processes related to our overarching question. The martian atmosphere and surface are an overwhelmingly oxidizing environment, and life requires pairing of electron donors and electron acceptors, that is, redox gradients, as an essential source of energy. Therefore, a fundamental and critical question regarding the possibility of life on Mars is, "Where can we find redox gradients as energy sources for life on Mars?" Hence, regardless of the pathway that generates CH4 on Mars, the presence of CH4, a reduced species in an oxidant-rich environment, suggests the possibility of redox gradients supporting life and habitability on Mars. Recent missions such as ExoMars Trace Gas Orbiter may provide mapping of the global distribution of CH4. To discriminate between abiotic and biotic sources of CH4 on Mars, future studies should use a series of diagnostic geochemical analyses, preferably performed below the ground or at the ground/atmosphere interface, including measurements of CH4 isotopes, methane/ethane ratios, H2 gas concentration, and species such as acetic acid. Advances in the fields of Mars exploration and instrumentation will be driven, augmented, and supported by an improved understanding of atmospheric chemistry and dynamics, deep subsurface biogeochemistry, astrobiology, planetary geology, and geophysics. Future Mars exploration programs will have to expand the integration of complementary areas of expertise to generate synergistic and innovative ideas to realize breakthroughs in advancing our understanding of the potential of life and habitable conditions having existed on Mars. In this spirit, we conducted a set of interdisciplinary workshops. From this series has emerged a vision of technological, theoretical, and methodological innovations to explore the martian subsurface and to enhance spatial tracking of key volatiles, such as CH4.
Collapse
Affiliation(s)
- Yuk L. Yung
- California Institute of Technology, Pasadena, California
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Pin Chen
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | | | | | | | - Jennifer G. Blank
- NASA Ames Research Center, Blue Marble Space Institute of Science, Mountain View, California
| | - Bethany Ehlmann
- California Institute of Technology, Pasadena, California
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - John Eiler
- California Institute of Technology, Pasadena, California
| | - Giuseppe Etiope
- Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
- Faculty of Environmental Science and Engineering, Babes-Bolyai University, Cluj-Napoca, Romania
| | - James G. Ferry
- The Pennsylvania State University, University Park, Pennsylvania
| | - Francois Forget
- Laboratoire de Météorologie Dynamique, Institut Pierre Simon Laplace, CNRS, Paris, France
| | - Peter Gao
- University of California, Berkeley, California
| | - Renyu Hu
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Armin Kleinböhl
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | | | - Franck Lefèvre
- Laboratoire Atmospheres, Milieux, Observations Spatiales (LATMOS), IPSL, Paris, France
| | - Charles Miller
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Michael Mischna
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Michael Mumma
- NASA Goddard Space Flight Center, Greenbelt, Maryland
| | - Sally Newman
- California Institute of Technology, Pasadena, California
| | | | | | | | | | - Radu Popa
- University of Southern California, Los Angeles, California
| | - Michael Russell
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Linhan Shen
- California Institute of Technology, Pasadena, California
| | | | - Robert Staehle
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | - Vlada Stamenković
- California Institute of Technology, Pasadena, California
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | | | | | - Ann C. Vandaele
- The Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
| | - Sébastien Viscardy
- The Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
| | - Christopher R. Webster
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| | | | | | - John Worden
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
| |
Collapse
|
13
|
Branscomb E, Russell MJ. Frankenstein or a Submarine Alkaline Vent: Who is Responsible for Abiogenesis? Bioessays 2018; 40:e1700182. [DOI: 10.1002/bies.201700182] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 04/26/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Elbert Branscomb
- Department of Physics; Carl R. Woese Institute for Genomic Biology; University of Illinois; Urbana IL 61801 USA
| | - Michael J. Russell
- Planetary Chemistry and Astrobiology; Sec. 3225 MS:183-301; Jet Propulsion Laboratory; California Institute of Technology; Pasadena CA 91109-8099 USA
| |
Collapse
|
14
|
Cheng H, Song W, Nie R, Wang YX, Li HL, Jiang XS, Wu JJ, Chen C, Wu QY. Synthesis of new 4-aryloxy- N -arylanilines and their inhibitory activities against succinate-cytochrome c reductase. Bioorg Med Chem Lett 2018; 28:1330-1335. [DOI: 10.1016/j.bmcl.2018.03.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 01/23/2018] [Accepted: 03/05/2018] [Indexed: 11/26/2022]
|
15
|
Zhang R, Wu QY, Tao J, Pan JH, Yang GF. An ionic liquid promoted approach to bitriazolyl compounds as succinate–ubiquinone oxidoreductase inhibitors. NEW J CHEM 2017. [DOI: 10.1039/c6nj02454h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Bitriazolyl compounds, a novel skeleton that is totally different from existing commercialized SQR-inhibiting fungicides, could provide a new lead for further development of SQR inhibitors.
Collapse
Affiliation(s)
- Rui Zhang
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry Central China Normal University
- Wuhan 430079
- P. R. China
| | - Qiong-You Wu
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry Central China Normal University
- Wuhan 430079
- P. R. China
| | - Jun Tao
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry Central China Normal University
- Wuhan 430079
- P. R. China
| | - Jin-Huan Pan
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry Central China Normal University
- Wuhan 430079
- P. R. China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry Central China Normal University
- Wuhan 430079
- P. R. China
| |
Collapse
|
16
|
Abstract
Biological electron transfer reactions between metal cofactors are critical to many essential processes within the cell. Duplex DNA is, moreover, capable of mediating the transport of charge through its π-stacked nitrogenous bases. Increasingly, [4Fe4S] clusters, generally redox-active cofactors, have been found to be associated with enzymes involved in DNA processing. DNA-binding enzymes containing [4Fe4S] clusters can thus utilize DNA charge transport (DNA CT) for redox signaling to coordinate reactions over long molecular distances. In particular, DNA CT signaling may represent the first step in the search for DNA lesions by proteins containing [4Fe4S] clusters that are involved in DNA repair. Here we describe research carried out to examine the chemical characteristics and biological consequences of DNA CT. We are finding that DNA CT among metalloproteins represents powerful chemistry for redox signaling at long range within the cell.
Collapse
Affiliation(s)
- Elizabeth O’Brien
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
| | - Rebekah M.B. Silva
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
| | - Jacqueline K. Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena CA 91125
| |
Collapse
|
17
|
Chen C, Wu QY, Shan LY, Zhang B, Verpoort F, Yang GF. Discovery of cytochrome bc1 complex inhibitors inspired by the natural product karrikinolide. RSC Adv 2016. [DOI: 10.1039/c6ra19424a] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Novel and potent inhibitors targeting the cytochrome bc1 complex were discovered from the natural product karrikinolide for the first time.
Collapse
Affiliation(s)
- Cheng Chen
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing
- Wuhan University of Technology
- Wuhan 430070
- P. R. China
| | - Qiong-You Wu
- Key Laboratory of Pesticide & Chemical Biology
- College of Chemistry
- Central China Normal University
- Wuhan 430079
- P. R. China
| | - Lian-Ying Shan
- Key Laboratory of Pesticide & Chemical Biology
- College of Chemistry
- Central China Normal University
- Wuhan 430079
- P. R. China
| | - Bei Zhang
- Key Laboratory of Pesticide & Chemical Biology
- College of Chemistry
- Central China Normal University
- Wuhan 430079
- P. R. China
| | - Francis Verpoort
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing
- Wuhan University of Technology
- Wuhan 430070
- P. R. China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology
- College of Chemistry
- Central China Normal University
- Wuhan 430079
- P. R. China
| |
Collapse
|
18
|
Borek A, Kuleta P, Ekiert R, Pietras R, Sarewicz M, Osyczka A. Mitochondrial Disease-related Mutation G167P in Cytochrome b of Rhodobacter capsulatus Cytochrome bc1 (S151P in Human) Affects the Equilibrium Distribution of [2Fe-2S] Cluster and Generation of Superoxide. J Biol Chem 2015; 290:23781-92. [PMID: 26245902 PMCID: PMC4583038 DOI: 10.1074/jbc.m115.661314] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Indexed: 12/04/2022] Open
Abstract
Cytochrome bc1 is one of the key enzymes of many bioenergetic systems. Its operation involves a large scale movement of a head domain of iron-sulfur protein (ISP-HD), which functionally connects the catalytic quinol oxidation Qo site in cytochrome b with cytochrome c1. The Qo site under certain conditions can generate reactive oxygen species in the reaction scheme depending on the actual position of ISP-HD in respect to the Qo site. Here, using a bacterial system, we show that mutation G167P in cytochrome b shifts the equilibrium distribution of ISP-HD toward positions remote from the Qo site. This renders cytochrome bc1 non-functional in vivo. This effect is remediated by addition of alanine insertions (1Ala and 2Ala) in the neck region of the ISP subunit. These insertions, which on their own shift the equilibrium distribution of ISP-HD in the opposite direction (i.e. toward the Qo site), also act in this manner in the presence of G167P. Changes in the equilibrium distribution of ISP-HD in G167P lead to an increased propensity of cytochrome bc1 to generate superoxide, which becomes evident when the concentration of quinone increases. This result corroborates the recently proposed model in which “semireverse” electron transfer back to the Qo site, occurring when ISP-HD is remote from the site, favors reactive oxygen species production. G167P suggests possible molecular effects of S151P (corresponding in sequence to G167P) identified as a mitochondrial disease-related mutation in human cytochrome b. These effects may be valid for other human mutations that change the equilibrium distribution of ISP-HD in a manner similar to G167P.
Collapse
Affiliation(s)
- Arkadiusz Borek
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Patryk Kuleta
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Robert Ekiert
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Rafał Pietras
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Marcin Sarewicz
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Artur Osyczka
- From the Department of Molecular Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| |
Collapse
|
19
|
Markevich NI, Hoek JB. Computational modeling analysis of mitochondrial superoxide production under varying substrate conditions and upon inhibition of different segments of the electron transport chain. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1847:656-79. [PMID: 25868872 PMCID: PMC4426091 DOI: 10.1016/j.bbabio.2015.04.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 03/24/2015] [Accepted: 04/06/2015] [Indexed: 12/13/2022]
Abstract
A computational mechanistic model of superoxide (O2•-) formation in the mitochondrial electron transport chain (ETC) was developed to facilitate the quantitative analysis of factors controlling mitochondrial O2•- production and assist in the interpretation of experimental studies. The model takes into account all individual electron transfer reactions in Complexes I and III. The model accounts for multiple, often seemingly contradictory observations on the effects of ΔΨ and ΔpH, and for the effects of multiple substrate and inhibitor conditions, including differential effects of Complex III inhibitors antimycin A, myxothiazol and stigmatellin. Simulation results confirm that, in addition to O2•- formation in Complex III and at the flavin site of Complex I, the quinone binding site of Complex I is an additional superoxide generating site that accounts for experimental observations on O2•- production during reverse electron transfer. However, our simulation results predict that, when cytochrome c oxidase is inhibited during oxidation of succinate, ROS production at this site is eliminated and almost all superoxide in Complex I is generated by reduced FMN, even when the redox pressure for reverse electron transfer from succinate is strong. In addition, the model indicates that conflicting literature data on the kinetics of electron transfer in Complex III involving the iron-sulfur protein-cytochrome bL complex can be resolved in favor of a dissociation of the protein only after electron transfer to cytochrome bH. The model predictions can be helpful in understanding factors driving mitochondrial superoxide formation in intact cells and tissues.
Collapse
Affiliation(s)
- Nikolai I Markevich
- MitoCare Center for Mitochondrial Research, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA; Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region 14290, Russia.
| | - Jan B Hoek
- MitoCare Center for Mitochondrial Research, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| |
Collapse
|
20
|
Cheng H, Shen YQ, Pan XY, Hou YP, Wu QY, Yang GF. Discovery of 1,2,4-triazole-1,3-disulfonamides as dual inhibitors of mitochondrial complex II and complex III. NEW J CHEM 2015. [DOI: 10.1039/c5nj00215j] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1,2,4-Triazole-1,3-disulfonamide derivatives as dual function inhibitors of mitochondrial complex II (SQR) and complex III (cyt bc1) were discovered.
Collapse
Affiliation(s)
- Hua Cheng
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
- Wuhan 430079
| | - Yan-Qing Shen
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
- Wuhan 430079
| | - Xia-Yan Pan
- Department of Pesticide Science
- College of Plant Protection
- Nanjing Agricultural University
- Nanjing 210095
- P. R. China
| | - Yi-Ping Hou
- Department of Pesticide Science
- College of Plant Protection
- Nanjing Agricultural University
- Nanjing 210095
- P. R. China
| | - Qiong-You Wu
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
- Wuhan 430079
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education
- College of Chemistry
- Central China Normal University
- Wuhan 430079
| |
Collapse
|
21
|
Xia D, Esser L, Tang WK, Zhou F, Zhou Y, Yu L, Yu CA. Structural analysis of cytochrome bc1 complexes: implications to the mechanism of function. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1827:1278-94. [PMID: 23201476 PMCID: PMC3593749 DOI: 10.1016/j.bbabio.2012.11.008] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 11/13/2012] [Accepted: 11/19/2012] [Indexed: 01/18/2023]
Abstract
The cytochrome bc1 complex (bc1) is the mid-segment of the cellular respiratory chain of mitochondria and many aerobic prokaryotic organisms; it is also part of the photosynthetic apparatus of non-oxygenic purple bacteria. The bc1 complex catalyzes the reaction of transferring electrons from the low potential substrate ubiquinol to high potential cytochrome c. Concomitantly, bc1 translocates protons across the membrane, contributing to the proton-motive force essential for a variety of cellular activities such as ATP synthesis. Structural investigations of bc1 have been exceedingly successful, yielding atomic resolution structures of bc1 from various organisms and trapped in different reaction intermediates. These structures have confirmed and unified results of decades of experiments and have contributed to our understanding of the mechanism of bc1 functions as well as its inactivation by respiratory inhibitors. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
Collapse
Affiliation(s)
- Di Xia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | | | | | | | | |
Collapse
|
22
|
Li H, Zhu XL, Yang WC, Yang GF. Comparative Kinetics ofQiSite Inhibitors of Cytochromebc1Complex: Picomolar Antimycin and Micromolar Cyazofamid. Chem Biol Drug Des 2013; 83:71-80. [DOI: 10.1111/cbdd.12199] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/17/2013] [Accepted: 07/26/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Hui Li
- Key Laboratory of Pesticide & Chemical Biology; College of Chemistry; Ministry of Education; Central China Normal University; Wuhan 430079 China
| | - Xiao-Lei Zhu
- Key Laboratory of Pesticide & Chemical Biology; College of Chemistry; Ministry of Education; Central China Normal University; Wuhan 430079 China
| | - Wen-Chao Yang
- Key Laboratory of Pesticide & Chemical Biology; College of Chemistry; Ministry of Education; Central China Normal University; Wuhan 430079 China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology; College of Chemistry; Ministry of Education; Central China Normal University; Wuhan 430079 China
| |
Collapse
|
23
|
Saen-Oon S, Lucas MF, Guallar V. Electron transfer in proteins: theory, applications and future perspectives. Phys Chem Chem Phys 2013; 15:15271-85. [DOI: 10.1039/c3cp50484k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
24
|
Millett F, Havens J, Rajagukguk S, Durham B. Design and use of photoactive ruthenium complexes to study electron transfer within cytochrome bc1 and from cytochrome bc1 to cytochrome c. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:1309-19. [PMID: 22985600 DOI: 10.1016/j.bbabio.2012.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/29/2012] [Accepted: 09/03/2012] [Indexed: 10/27/2022]
Abstract
The cytochrome bc1 complex (ubiquinone:cytochrome c oxidoreductase) is the central integral membrane protein in the mitochondrial respiratory chain as well as the electron-transfer chains of many respiratory and photosynthetic prokaryotes. Based on X-ray crystallographic studies of cytochrome bc1, a mechanism has been proposed in which the extrinsic domain of the iron-sulfur protein first binds to cytochrome b where it accepts an electron from ubiquinol in the Qo site, and then rotates by 57° to a position close to cytochrome c1 where it transfers an electron to cytochrome c1. This review describes the development of a ruthenium photooxidation technique to measure key electron transfer steps in cytochrome bc1, including rapid electron transfer from the iron-sulfur protein to cytochrome c1. It was discovered that this reaction is rate-limited by the rotational dynamics of the iron-sulfur protein rather than true electron transfer. A conformational linkage between the occupant of the Qo ubiquinol binding site and the rotational dynamics of the iron-sulfur protein was discovered which could play a role in the bifurcated oxidation of ubiquinol. A ruthenium photoexcitation method is also described for the measurement of electron transfer from cytochrome c1 to cytochrome c. This article is part of a Special Issue entitled: Respiratory Complex III and related bc complexes.
Collapse
Key Words
- 2,2′-bipyrazine
- 2,2′-bipyridine
- 2,2′:4′,4″:2″,2‴-quaterpyridine
- 2Fe2S
- 3,3′-bipyridazine
- 4,4′-dimethyl-2,2′-bipridine
- Cc
- CcO
- Cytochrome bc(1)
- Cytochrome c
- Electron transfer
- ISP
- JG144
- MOAS
- P(f)
- P(m)
- Q
- Q(i)
- Q(o)
- Q(o) site inhibitor which fixes ISP in b state
- Q(o) site inhibitor which promotes mobile state of ISP
- QH(2)
- R. sphaeroides
- Rhodobacter sphaeroides
- Rieske iron–sulfur center
- Ru(2)D
- Ruthenium
- S-3-anilino-5-methyl-5-(4,6-difluorophenyl)-1,3-oxazolidine-2,4-dione
- [Ru(bpy)(2)](2)qpy(4+)
- bpd
- bpy
- bpz
- cyt bc(1)
- cytochrome bc(1)
- cytochrome c
- cytochrome c oxidase
- dmb
- inside ubiquinone binding site
- iron–sulfur protein
- methoxyacrylate stilbene
- outside ubiquinol binding site
- qpy
- ubiquinol
- ubiquionone
- yCc
- yeast Cc
Collapse
Affiliation(s)
- Francis Millett
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.
| | | | | | | |
Collapse
|
25
|
Buckel W, Thauer RK. Energy conservation via electron bifurcating ferredoxin reduction and proton/Na(+) translocating ferredoxin oxidation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:94-113. [PMID: 22800682 DOI: 10.1016/j.bbabio.2012.07.002] [Citation(s) in RCA: 501] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/05/2012] [Accepted: 07/07/2012] [Indexed: 01/21/2023]
Abstract
The review describes four flavin-containing cytoplasmatic multienzyme complexes from anaerobic bacteria and archaea that catalyze the reduction of the low potential ferredoxin by electron donors with higher potentials, such as NAD(P)H or H(2) at ≤ 100 kPa. These endergonic reactions are driven by concomitant oxidation of the same donor with higher potential acceptors such as crotonyl-CoA, NAD(+) or heterodisulfide (CoM-S-S-CoB). The process called flavin-based electron bifurcation (FBEB) can be regarded as a third mode of energy conservation in addition to substrate level phosphorylation (SLP) and electron transport phosphorylation (ETP). FBEB has been detected in the clostridial butyryl-CoA dehydrogenase/electron transferring flavoprotein complex (BcdA-EtfBC), the multisubunit [FeFe]hydrogenase from Thermotoga maritima (HydABC) and from acetogenic bacteria, the [NiFe]hydrogenase/heterodisulfide reductase (MvhADG-HdrABC) from methanogenic archaea, and the transhydrogenase (NfnAB) from many Gram positive and Gram negative bacteria and from anaerobic archaea. The Bcd/EtfBC complex that catalyzes electron bifurcation from NADH to the low potential ferredoxin and to the high potential crotonyl-CoA has already been studied in some detail. The bifurcating protein most likely is EtfBC, which in each subunit (βγ) contains one FAD. In analogy to the bifurcating complex III of the mitochondrial respiratory chain and with the help of the structure of the human ETF, we propose a conformational change by which γ-FADH(-) in EtfBC approaches β-FAD to enable the bifurcating one-electron transfer. The ferredoxin reduced in one of the four electron bifurcating reactions can regenerate H(2) or NADPH, reduce CO(2) in acetogenic bacteria and methanogenic archaea, or is converted to ΔμH(+)/Na(+) by the membrane-associated enzyme complexes Rnf and Ech, whereby NADH and H(2) are recycled, respectively. The mainly bacterial Rnf complexes couple ferredoxin oxidation by NAD(+) with proton/sodium ion translocation and the more diverse energy converting [NiFe]hydrogenases (Ech) do the same, whereby NAD(+) is replaced by H(+). Many organisms also use Rnf and Ech in the reverse direction to reduce ferredoxin driven by ΔμH(+)/Na(+). Finally examples are shown, in which the four bifurcating multienzyme complexes alone or together with Rnf and Ech are integrated into energy metabolisms of nine anaerobes. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems.
Collapse
Affiliation(s)
- Wolfgang Buckel
- Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Str. 10, 35043 Marburg, and Fachbereich Biologie, Philipps-Universität, Marburg, Germany.
| | | |
Collapse
|
26
|
Yang WC, Li H, Wang F, Zhu XL, Yang GF. Rieske Iron-Sulfur Protein of the Cytochrome bc1 Complex: A Potential Target for Fungicide Discovery. Chembiochem 2012; 13:1542-51. [DOI: 10.1002/cbic.201200295] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Indexed: 01/17/2023]
|
27
|
Havens J, Castellani M, Kleinschroth T, Ludwig B, Durham B, Millett F. Photoinitiated electron transfer within the Paracoccus denitrificans cytochrome bc1 complex: mobility of the iron-sulfur protein is modulated by the occupant of the Q(o) site. Biochemistry 2011; 50:10462-72. [PMID: 22026826 DOI: 10.1021/bi200453r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Domain rotation of the Rieske iron-sulfur protein (ISP) between the cytochrome (cyt) b and cyt c(1) redox centers plays a key role in the mechanism of the cyt bc(1) complex. Electron transfer within the cyt bc(1) complex of Paracoccus denitrificans was studied using a ruthenium dimer to rapidly photo-oxidize cyt c(1) within 1 μs and initiate the reaction. In the absence of any added quinol or inhibitor of the bc(1) complex at pH 8.0, electron transfer from reduced ISP to cyt c(1) was biphasic with rate constants of k(1f) = 6300 ± 3000 s(-1)and k(1s) = 640 ± 300 s(-1) and amplitudes of 10 ± 3% and 16 ± 4% of the total amount of cyt c(1) photooxidized. Upon addition of any of the P(m) type inhibitors MOA-stilbene, myxothiazol, or azoxystrobin to cyt bc(1) in the absence of quinol, the total amplitude increased 2-fold, consistent with a decrease in redox potential of the ISP. In addition, the relative amplitude of the fast phase increased significantly, consistent with a change in the dynamics of the ISP domain rotation. In contrast, addition of the P(f) type inhibitors JG-144 and famoxadone decreased the rate constant k(1f) by 5-10-fold and increased the amplitude over 2-fold. Addition of quinol substrate in the absence of inhibitors led to a 2-fold increase in the amplitude of the k(1f) phase. The effect of QH(2) on the kinetics of electron transfer from reduced ISP to cyt c(1) was thus similar to that of the P(m) inhibitors and very different from that of the P(f) inhibitors. The current results indicate that the species occupying the Q(o) site has a significant conformational influence on the dynamics of the ISP domain rotation.
Collapse
Affiliation(s)
- Jeffrey Havens
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | | | | | | | | | | |
Collapse
|
28
|
The Rieske Iron-Sulfur Protein: Import and Assembly into the Cytochrome bc(1) Complex of Yeast Mitochondria. Bioinorg Chem Appl 2011; 2011:363941. [PMID: 21716720 PMCID: PMC3119413 DOI: 10.1155/2011/363941] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/12/2011] [Indexed: 11/17/2022] Open
Abstract
The Rieske iron-sulfur protein, one of the catalytic subunits of the cytochrome bc1 complex, is involved in electron transfer at the level of the inner membrane of yeast mitochondria. The Rieske iron-sulfur protein is encoded by nuclear DNA and, after being synthesized in the cytosol, is imported into mitochondria with the help of a cleavable N-terminal presequence. The imported protein, besides incorporating the 2Fe-2S cluster, also interacts with other catalytic and non-catalytic subunits of the cytochrome bc1 complex, thereby assembling into the mature and functional respiratory complex. In this paper, we summarize the most recent findings on the import and assembly of the Rieske iron-sulfur protein into Saccharomyces cerevisiae mitochondria, also discussing a possible role of this protein both in the dimerization of the cytochrome bc1 complex and in the interaction of this homodimer with other complexes of the mitochondrial respiratory chain.
Collapse
|
29
|
Pereira IAC, Ramos AR, Grein F, Marques MC, da Silva SM, Venceslau SS. A comparative genomic analysis of energy metabolism in sulfate reducing bacteria and archaea. Front Microbiol 2011; 2:69. [PMID: 21747791 PMCID: PMC3119410 DOI: 10.3389/fmicb.2011.00069] [Citation(s) in RCA: 215] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 03/25/2011] [Indexed: 11/13/2022] Open
Abstract
The number of sequenced genomes of sulfate reducing organisms (SRO) has increased significantly in the recent years, providing an opportunity for a broader perspective into their energy metabolism. In this work we carried out a comparative survey of energy metabolism genes found in 25 available genomes of SRO. This analysis revealed a higher diversity of possible energy conserving pathways than classically considered to be present in these organisms, and permitted the identification of new proteins not known to be present in this group. The Deltaproteobacteria (and Thermodesulfovibrio yellowstonii) are characterized by a large number of cytochromes c and cytochrome c-associated membrane redox complexes, indicating that periplasmic electron transfer pathways are important in these bacteria. The Archaea and Clostridia groups contain practically no cytochromes c or associated membrane complexes. However, despite the absence of a periplasmic space, a few extracytoplasmic membrane redox proteins were detected in the Gram-positive bacteria. Several ion-translocating complexes were detected in SRO including H(+)-pyrophosphatases, complex I homologs, Rnf, and Ech/Coo hydrogenases. Furthermore, we found evidence that cytoplasmic electron bifurcating mechanisms, recently described for other anaerobes, are also likely to play an important role in energy metabolism of SRO. A number of cytoplasmic [NiFe] and [FeFe] hydrogenases, formate dehydrogenases, and heterodisulfide reductase-related proteins are likely candidates to be involved in energy coupling through electron bifurcation, from diverse electron donors such as H(2), formate, pyruvate, NAD(P)H, β-oxidation, and others. In conclusion, this analysis indicates that energy metabolism of SRO is far more versatile than previously considered, and that both chemiosmotic and flavin-based electron bifurcating mechanisms provide alternative strategies for energy conservation.
Collapse
Affiliation(s)
- Inês A Cardoso Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa Oeiras, Portugal
| | | | | | | | | | | |
Collapse
|
30
|
Farhana A, Guidry L, Srivastava A, Singh A, Hondalus MK, Steyn AJC. Reductive stress in microbes: implications for understanding Mycobacterium tuberculosis disease and persistence. Adv Microb Physiol 2011; 57:43-117. [PMID: 21078441 DOI: 10.1016/b978-0-12-381045-8.00002-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is a remarkably successful pathogen that is capable of persisting in host tissues for decades without causing disease. Years after initial infection, the bacilli may resume growth, the outcome of which is active tuberculosis (TB). In order to establish infection, resist host defences and re-emerge, Mtb must coordinate its metabolism with the in vivo environmental conditions and nutrient availability within the primary site of infection, the lung. Maintaining metabolic homeostasis for an intracellular pathogen such as Mtb requires a carefully orchestrated series of oxidation-reduction reactions, which, if unbalanced, generate oxidative or reductive stress. The importance of oxidative stress in microbial pathogenesis has been appreciated and well studied over the past several decades. However, the role of its counterpart, reductive stress, has been largely ignored. Reductive stress is defined as an aberrant increase in reducing equivalents, the magnitude and identity of which is determined by host carbon source utilisation and influenced by the presence of host-generated gases (e.g. NO, CO, O(2) and CO(2)). This increased reductive power must be dissipated for bacterial survival. To recycle reducing equivalents, microbes have evolved unique electron 'sinks' that are distinct for their particular environmental niche. In this review, we describe the specific mechanisms that some microbes have evolved to dispel reductive stress. The intention of this review is to introduce the concept of reductive stress, in tuberculosis research in particular, in the hope of stimulating new avenues of investigation.
Collapse
Affiliation(s)
- Aisha Farhana
- Department of Microbiology, University of Alabama at Birmingham, AL, USA
| | | | | | | | | | | |
Collapse
|
31
|
Cramer WA, Hasan SS, Yamashita E. The Q cycle of cytochrome bc complexes: a structure perspective. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:788-802. [PMID: 21352799 DOI: 10.1016/j.bbabio.2011.02.006] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 02/08/2011] [Accepted: 02/13/2011] [Indexed: 12/01/2022]
Abstract
Aspects of the crystal structures of the hetero-oligomeric cytochrome bc(1) and b(6)f ("bc") complexes relevant to their electron/proton transfer function and the associated redox reactions of the lipophilic quinones are discussed. Differences between the b(6)f and bc(1) complexes are emphasized. The cytochrome bc(1) and b(6)f dimeric complexes diverge in structure from a core of subunits that coordinate redox groups consisting of two bis-histidine coordinated hemes, a heme b(n) and b(p) on the electrochemically negative (n) and positive (p) sides of the complex, the high potential [2Fe-2S] cluster and c-type heme at the p-side aqueous interface and aqueous phase, respectively, and quinone/quinol binding sites on the n- and p-sides of the complex. The bc(1) and b(6)f complexes diverge in subunit composition and structure away from this core. b(6)f Also contains additional prosthetic groups including a c-type heme c(n) on the n-side, and a chlorophyll a and β-carotene. Common structure aspects; functions of the symmetric dimer. (I) Quinone exchange with the bilayer. An inter-monomer protein-free cavity of approximately 30Å along the membrane normal×25Å (central inter-monomer distance)×15Å (depth in the center), is common to both bc(1) and b(6)f complexes, providing a niche in which the lipophilic quinone/quinol (Q/QH(2)) can be exchanged with the membrane bilayer. (II) Electron transfer. The dimeric structure and the proximity of the two hemes b(p) on the electrochemically positive side of the complex in the two monomer units allow the possibility of two alternate routes of electron transfer across the complex from heme b(p) to b(n): intra-monomer and inter-monomer involving electron cross-over between the two hemes b(p). A structure-based summary of inter-heme distances in seven bc complexes, representing mitochondrial, chromatophore, cyanobacterial, and algal sources, indicates that, based on the distance parameter, the intra-monomer pathway would be favored kinetically. (III) Separation of quinone binding sites. A consequence of the dimer structure and the position of the Q/QH(2) binding sites is that the p-side QH(2) oxidation and n-side Q reduction sites are each well separated. Therefore, in the event of an overlap in residence time by QH(2) or Q molecules at the two oxidation or reduction sites, their spatial separation would result in minimal steric interference between extended Q or QH(2) isoprenoid chains. (IV) Trans-membrane QH(2)/Q transfer. (i) n/p-side QH(2)/Q transfer may be hindered by lipid acyl chains; (ii) the shorter less hindered inter-monomer pathway across the complex would not pass through the center of the cavity, as inferred from the n-side antimycin site on one monomer and the p-side stigmatellin site on the other residing on the same surface of the complex. (V) Narrow p-side portal for QH(2)/Q passage. The [2Fe-2S] cluster that serves as oxidant, and whose histidine ligand serves as a H(+) acceptor in the oxidation of QH(2), is connected to the inter-monomer cavity by a narrow extended portal, which is also occupied in the b(6)f complex by the 20 carbon phytyl chain of the bound chlorophyll.
Collapse
Affiliation(s)
- William A Cramer
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.
| | | | | |
Collapse
|
32
|
Mulkidjanian AY. Activated Q-cycle as a common mechanism for cytochrome bc1 and cytochrome b6f complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1858-68. [DOI: 10.1016/j.bbabio.2010.07.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 03/14/2010] [Accepted: 07/13/2010] [Indexed: 10/19/2022]
|
33
|
Gray HB, Winkler JR. Electron flow through metalloproteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1563-72. [PMID: 20460102 DOI: 10.1016/j.bbabio.2010.05.001] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/21/2010] [Accepted: 05/03/2010] [Indexed: 01/23/2023]
Abstract
Electron transfers in photosynthesis and respiration commonly occur between metal-containing cofactors that are separated by large molecular distances. Understanding the underlying physics and chemistry of these biological electron transfer processes is the goal of much of the work in our laboratories. Employing laser flash-quench triggering methods, we have shown that 20A, coupling-limited Fe(II) to Ru(III) and Cu(I) to Ru(III) electron tunneling in Ru-modified cytochromes and blue copper proteins can occur on the microsecond timescale both in solutions and crystals; and, further, that analysis of these rates suggests that distant donor-acceptor electronic couplings are mediated by a combination of sigma and hydrogen bonds in folded polypeptide structures. Redox equivalents can be transferred even longer distances by multistep tunneling, often called hopping, through intervening amino acid side chains. In recent work, we have found that 20A hole hopping through an intervening tryptophan is several hundred-fold faster than single-step electron tunneling in a Re-modified blue copper protein.
Collapse
Affiliation(s)
- Harry B Gray
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA.
| | | |
Collapse
|
34
|
Wang Q, Yu L, Yu CA. Cross-talk between mitochondrial malate dehydrogenase and the cytochrome bc1 complex. J Biol Chem 2010; 285:10408-14. [PMID: 20075069 DOI: 10.1074/jbc.m109.085787] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The interactions between the mitochondrial cytochrome bc(1) complex and matrix-soluble proteins were studied by a precipitation pulldown technique. Purified, detergent-dispersed bc(1) complex was incubated with mitochondrial matrix proteins followed by dialysis in the absence of detergent. The interacting protein(s) was co-precipitated with bc(1) complex upon centrifugation. One of the matrix proteins pulled down by bc(1) complex was identified as mitochondrial malate dehydrogenase (MDH) by matrix-assisted laser desorption ionization time-of-flight mass spectrometry and confirmed by Western blotting with anti-MDH antibody. Using a cross-linking technique, subunits I, II (core I and II), and V of the bc(1) complex were identified as the interacting sites for MDH. Incubating purified MDH with the detergent dispersed bc(1) complex results in an increase of the activities of both the bc(1) complex and MDH. The effect of the bc(1) complex on the activities of MDH is unidirectional (oxaloacetate --> malate). These results suggest that the novel cross-talk between citric acid cycle enzymes and electron transfer chain complexes might play a regulatory role in mitochondrial bioenergetics.
Collapse
Affiliation(s)
- Qiyu Wang
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma 74078, USA
| | | | | |
Collapse
|
35
|
Abstract
Electron transfers in photosynthesis and respiration commonly occur between metal-containing cofactors that are separated by large molecular distances. Employing laser flash-quench triggering methods, we have shown that 20-Å, coupling-limited Fe(II) to Ru(III) and Cu(I) to Ru(III) electron tunneling in Ru-modified cytochromes and blue copper proteins can occur on the microsecond timescale both in solutions and crystals. Redox equivalents can be transferred even longer distances by multistep tunneling, often called hopping, through intervening amino acid side chains. Our work has established that 20-Å hole hopping through an intervening tryptophan is two orders of magnitude faster than single-step electron tunneling in a Re-modified blue copper protein.
Collapse
Affiliation(s)
- Harry B Gray
- Beckman Institute, California Institute of Technology, Pasadena, California 91125
| | | |
Collapse
|
36
|
Cooley JW, Lee DW, Daldal F. Across membrane communication between the Q(o) and Q(i) active sites of cytochrome bc(1). Biochemistry 2009; 48:1888-99. [PMID: 19254042 DOI: 10.1021/bi802216h] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ubihydroquinone:cytochrome c oxidoreductase (cyt bc(1)) contains two catalytically active domains, termed the hydroquinone oxidation (Q(o)) and quinone reduction (Q(i)) sites, which are distant from each other by over 30 A. Previously, we have reported that binding of inhibitors to the Q(i) site on one (n) side of the energy-transducing membrane changes the local environment of the iron-sulfur (Fe/S) protein subunit residing in the Q(o) site on the other (p) side of the lipid bilayer [Cooley, J. W., Ohnishi, T., and Daldal, F. (2005) Biochemistry 44, 10520-10532]. These findings best fit a model whereby the Q(o) and Q(i) sites of the cyt bc(1) are actively coupled in spite of their distant locations. Because the Fe/S protein of the cyt bc(1) undergoes a large-scale (macro) domain movement during catalysis, we examined various macromobility-defective Fe/S subunit mutants to assess the role of this motion on the coupling of the active sites and also during the multiple turnovers of the enzyme. By monitoring the changing environments of the Fe/S protein [2Fe-2S] cluster upon addition of Q(i) site inhibitors in selected mutants, we found that the Q(o)-Q(i) site interactions manifest differently depending on the ability of the Fe/S protein to move between the cytochrome b and cytochrome c(1) subunits of the enzyme. In the presence of antimycin A, an immobile Fe/S protein mutant exhibited no changes in its EPR spectra. In contrast, mobility-restricted mutants showed striking alterations in the EPR line shapes and revealed two discrete subpopulations in respect to the [2Fe-2S] cluster environments at the Q(o) site. These findings led us to conclude that the mobility of the Fe/S protein is involved in its response to the occupancy of the Q(i) site by different molecules. We propose that the heterogeneity seen might reflect the distinct responses of the two Fe/S proteins at the Q(o) sites of the dimeric enzyme upon the occupancy of the Q(i) sites and discuss it in terms of the function of the dimeric cyt bc(1) during its multiple turnovers.
Collapse
Affiliation(s)
- Jason W Cooley
- Department of Biology, Plant Science Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | | |
Collapse
|
37
|
Yu L, Yang S, Yin Y, Cen X, Zhou F, Xia D, Yu CA. Chapter 25 Analysis of electron transfer and superoxide generation in the cytochrome bc1 complex. Methods Enzymol 2009; 456:459-73. [PMID: 19348904 DOI: 10.1016/s0076-6879(08)04425-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
During the electron transfer through the cytochrome bc(1) complex (ubiquinol-cytochrome c oxidoreductase or complex III), protons are translocated across the membrane, and production of superoxide anion radicals (O(2)(*-)) is observed. The bc(1) complex is purified from broken mitochondrial preparation prepared from frozen heart muscles by repeated detergent solubilization and salt fractionation. The electron transfer of the purified complex is determined spectrophotometrically. The activity depends on the choice of detergent, protein concentration, and ubiquinol derivatives used. The proton translocation activity of 2H(+)/e(-) is determined in the reconstituted bc(1)-PL vesicles. The O(2)(*-) production by bc(1) is determined by measuring the chemiluminescence of the 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazol[1,2-1]pyrazin-3-one hydrochloride (MCLA)-O(2)(*-) adduct during a single turnover of bc(1) complex, with the Applied Photophysics stopped-flow reaction analyzer SX.18MV, by leaving the excitation light source off and registering the light emission. Production of O(2)(*-) by bc(1) is in an inverse relationship to its electron transfer activity. Inactivation of the bc(1) complex by incubating at elevated temperature (37 degrees C) or by treatment with proteinase K results in an increase in O(2)(*-)-generating activity to the same level as that of the antimycin A-inhibited complex. These results suggest that the structural integrity of protein subunits is not required for O(2)(*-)-generating activity in the bc(1) complex.
Collapse
Affiliation(s)
- Linda Yu
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, USA
| | | | | | | | | | | | | |
Collapse
|
38
|
Van Nieuwenhuyse P, Van Leeuwen T, Khajehali J, Vanholme B, Tirry L. Mutations in the mitochondrial cytochrome b of Tetranychus urticae Koch (Acari: Tetranychidae) confer cross-resistance between bifenazate and acequinocyl. PEST MANAGEMENT SCIENCE 2009; 65:404-412. [PMID: 19165831 DOI: 10.1002/ps.1705] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
BACKGROUND Resistance of Tetranychus urticae Koch to bifenazate was recently linked with mutations in the mitochondrial cytochrome b Q(o) pocket, suggesting that bifenazate acts as a Q(o) inhibitor (Q(o)I). Since these mutations might cause cross-resistance to the known acaricidal Q(o)I acequinocyl and fluacrypyrim, resistance levels and inheritance patterns were investigated in several bifenazate-susceptible and bifenazate-resistant strains with different mutations in the cd1 and ef helices aligning the Q(o) pocket. RESULTS Cross-resistance to acequinocyl in two bifenazate-resistant strains was shown to be maternally inherited and caused by the combination of two specific mutations in the cytochrome b Q(o) pocket. Although most investigated strains were resistant to fluacrypyrim, resistance was not inherited maternally, but as a monogenic autosomal highly dominant trait. As a consequence, there was no correlation between cytochrome b genotype and fluacrypyrim resistance. CONCLUSIONS Although there is no absolute cross-resistance between bifenazate, acequinocyl and fluacrypyrim, some bifenazate resistance mutations confer cross-resistance to acequinocyl. In the light of resistance development and management, high prudence is called for when alternating bifenazate and acequinocyl in the same crop. Maternally inherited cross-resistance between bifenazate and acequinocyl reinforces the likelihood of bifenazate acting as a mitochondrial complex III inhibitor at the Q(o) site.
Collapse
Affiliation(s)
- Pieter Van Nieuwenhuyse
- Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B9000 Ghent, Belgium
| | | | | | | | | |
Collapse
|
39
|
Yang S, Ma HW, Yu L, Yu CA. On the mechanism of quinol oxidation at the QP site in the cytochrome bc1 complex: studied using mutants lacking cytochrome bL or bH. J Biol Chem 2008; 283:28767-76. [PMID: 18713733 DOI: 10.1074/jbc.m803013200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To elucidate the mechanism of bifurcated oxidation of quinol in the cytochrome bc1 complex, Rhodobacter sphaeroides mutants, H198N and H111N, lacking heme bL and heme bH, respectively, were constructed and characterized. Purified mutant complexes have the same subunit composition as that of the wild-type complex, but have only 9-11% of the electron transfer activity, which is sensitive to stigmatellin or myxothiazol. The Em values for hemes bL and bH in the H111N and H198N complexes are -95 and -35 mV, respectively. The pseudo first-order reduction rate constants for hemes bL and bH in H111N and H198N, by ubiquiniol, are 16.3 and 12.4 s(-1), respectively. These indicate that the Qp site in the H111N mutant complex is similar to that in the wild-type complex. Pre-steady state reduction rates of heme c1 by these two mutant complexes decrease to a similar extent of their activity, suggesting that the decrease in electron transfer activity is due to impairment of movement of the head domain of reduced iron-sulfur protein, caused by disruption of electron transfer from heme bL to heme bH. Both mutant complexes produce as much superoxide as does antimycin A-treated wild-type complex. Ascorbate eliminates all superoxide generating activity in the intact or antimycin inhibited wild-type or mutant complexes.
Collapse
Affiliation(s)
- Shaoqing Yang
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma 74078, USA
| | | | | | | |
Collapse
|
40
|
Thauer RK, Kaster AK, Seedorf H, Buckel W, Hedderich R. Methanogenic archaea: ecologically relevant differences in energy conservation. Nat Rev Microbiol 2008; 6:579-91. [PMID: 18587410 DOI: 10.1038/nrmicro1931] [Citation(s) in RCA: 1083] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most methanogenic archaea can reduce CO(2) with H(2) to methane, and it is generally assumed that the reactions and mechanisms of energy conservation that are involved are largely the same in all methanogens. However, this does not take into account the fact that methanogens with cytochromes have considerably higher growth yields and threshold concentrations for H(2) than methanogens without cytochromes. These and other differences can be explained by the proposal outlined in this Review that in methanogens with cytochromes, the first and last steps in methanogenesis from CO(2) are coupled chemiosmotically, whereas in methanogens without cytochromes, these steps are energetically coupled by a cytoplasmic enzyme complex that mediates flavin-based electron bifurcation.
Collapse
Affiliation(s)
- Rudolf K Thauer
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany.
| | | | | | | | | |
Collapse
|
41
|
Yu CA, Cen X, Ma HW, Yin Y, Yu L, Esser L, Xia D. Domain conformational switch of the iron-sulfur protein in cytochrome bc1 complex is induced by the electron transfer from cytochrome bL to bH. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1038-43. [PMID: 18452702 DOI: 10.1016/j.bbabio.2008.03.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 03/06/2008] [Accepted: 03/25/2008] [Indexed: 11/30/2022]
Abstract
Intensive biochemical, biophysical and structural studies of the cytochrome (cyt) bc(1) complex in the past have led to the formulation of the "protonmotive Q-cycle" mechanism for electron and proton transfer in this vitally important complex. The key step of this mechanism is the separation of electrons during the oxidation of a substrate quinol at the Q(P) site with both electrons transferred simultaneously to ISP and cyt b(L) when the extrinsic domain of ISP (ISP-ED) is located at the b-position. Pre-steady state fast kinetic analysis of bc(1) demonstrates that the reduced ISP-ED moves to the c(1)-position to reduce cyt c(1) only after the reduced cyt b(L) is oxidized by cyt b(H). However, the question of how the conformational switch of ISP-ED is initiated remains unanswered. The results obtained from analysis of inhibitory efficacy and binding affinity of two types of Q(P) site inhibitors, Pm and Pf, under various redox states of the bc(1) complex, suggest that the electron transfer from heme b(L) to b(H) is the driving force for the releasing of the reduced ISP-ED from the b-position to c(1)-position to reduce cyt c(1).
Collapse
Affiliation(s)
- Chang-An Yu
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.
| | | | | | | | | | | | | |
Collapse
|
42
|
Cen X, Yu L, Yu CA. Domain movement of iron sulfur protein in cytochrome bc1 complex is facilitated by the electron transfer from cytochrome b(L) to b(H). FEBS Lett 2008; 582:523-6. [PMID: 18230359 DOI: 10.1016/j.febslet.2008.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 01/15/2008] [Accepted: 01/16/2008] [Indexed: 11/16/2022]
Abstract
The key step of the "protonmotive Q-cycle" mechanism for cytochrome bc1 complex is the bifurcated oxidation of ubiquinol at the Qp site. ISP is reduced when its head domain is at the b-position and subsequent move to the c1 position, to reduce cytochrome c1, upon protein conformational changes caused by the electron transfer from cytochrome b(L) to b(H). Results of analyses of the inhibitory efficacy and the binding affinity, determined by isothermal titration calorimetry, of Pm and Pf, on different redox states of cytochrome bc1 complexes, confirm this speculation. Pm inhibitor has a higher affinity and better efficacy with the cytochrome b(H) reduced complex and Pf binds better and has a higher efficacy with the ISP reduced complex.
Collapse
Affiliation(s)
- Xiaowei Cen
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | | | | |
Collapse
|
43
|
Lipids in the assembly of membrane proteins and organization of protein supercomplexes: implications for lipid-linked disorders. Subcell Biochem 2008; 49:197-239. [PMID: 18751913 DOI: 10.1007/978-1-4020-8831-5_8] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipids play important roles in cellular dysfunction leading to disease. Although a major role for phospholipids is in defining the membrane permeability barrier, phospholipids play a central role in a diverse range of cellular processes and therefore are important factors in cellular dysfunction and disease. This review is focused on the role of phospholipids in normal assembly and organization of the membrane proteins, multimeric protein complexes, and higher order supercomplexes. Since lipids have no catalytic activity, it is difficult to determine their function at the molecular level. Lipid function has generally been defined by affects on protein function or cellular processes. Molecular details derived from genetic, biochemical, and structural approaches are presented for involvement of phosphatidylethanolamine and cardiolipin in protein organization. Experimental evidence is presented that changes in phosphatidylethanolamine levels results in misfolding and topological misorientation of membrane proteins leading to dysfunctional proteins. Examples are presented for diseases in which proper protein folding or topological organization is not attained due to either demonstrated or proposed involvement of a lipid. Similar changes in cardiolipin levels affects the structure and function of individual components of the mitochondrial electron transport chain and their organization into supercomplexes resulting in reduced mitochondrial oxidative phosphorylation efficiency and apoptosis. Diseases in which mitochondrial dysfunction has been linked to reduced cardiolipin levels are described. Therefore, understanding the principles governing lipid-dependent assembly and organization of membrane proteins and protein complexes will be useful in developing novel therapeutic approaches for disorders in which lipids play an important role.
Collapse
|