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Abstract
In the past, many intensive attempts failed to capture or underestimated the copopulated intermediate conformers from the protein folding/unfolding reaction. We report a promising approach to kinetically trap, resolve, and quantify protein conformers that evolve during unfolding in solution. We conducted acid-induced unfolding of three model proteins (cytochrome c, myoglobin, and lysozyme), and the corresponding reaction aliquots upon decreasing the pH were electrosprayed for high field asymmetric waveform ion mobility spectrometry (FAIMS) measurements. The copopulated conformers were resolved, visualized, and quantified by a two-dimensional mapping of the FAIMS output. Contrary to expectations, all the above proteins appeared metamorphic (multiple-folded conformations) at the physiological pH, and cytochrome c exhibited an unusual "conformational shuttling" before forming the molten globule state. Thus, in contrast to many previous studies, a wide variety of thermodynamically stable intermediate conformers, including compact, molten globule, and partially unfolded forms, was trapped from solution, probing the unfolding mechanism in detail.
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Affiliation(s)
- Veena Shankar Avadhani
- Department of Chemistry, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
| | - Supratim Mondal
- Department of Chemistry, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
| | - Shibdas Banerjee
- Department of Chemistry, Indian Institute of Science Education and Research Tirupati, Tirupati 517507, India
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2
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Characterization of oxidation of glutathione by cytochrome c. J Bioenerg Biomembr 2021; 54:1-8. [PMID: 34893948 PMCID: PMC8789735 DOI: 10.1007/s10863-021-09926-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 10/22/2021] [Indexed: 10/29/2022]
Abstract
Cytochrome c is a member of the respiratory chain of the mitochondria. Non-membrane-bound (free) cytochrome c can be reduced by gluthatione as well as ascorbic acid. We investigated the effect of pH, Ca2+, Mg2+ and anionic phospholipids on the reduction of cytochrome c by glutathione.The reduction of cytochrome c by thiols was measured using photometry. Mitochondrial oxygen consumption was detected by use of oxygen electrode. Glutathione does not reduce cytochrome c at pH = 7.0 in the absence of Ca2+ and Mg2+. The reduction of cytochrome c by glutathione is inhibited by anionic lipids, especially cardiolipin. The typical conditions of apoptosis-elevated pH, Ca2+ level and Mg2+-increases the reduction of cytochrome c. Glutathione (5 mM) causes increased mitochondrial O2 consumption at pH = 8.0, in the presence of ADP either 1 mM Mg2+ or 1 mM Ca2+. Our results suggest that membrane bound cyt c does not oxidize glutathione. Free (not membrane bound) cytochrome c can oxidize glutathione. In mitochondria, O2 is depleted only in the presence of ADP, so the O2 depletion observed in the presence of glutathione can be related to the respiratory chain. Decreased glutathione levels play a role in apoptosis. Therefore, membrane unbound cyt c can contribute to apoptosis by oxidation of glutathione.
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3
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Koma R, Shibaguchi T, Pérez López C, Oka T, Jue T, Takakura H, Masuda K. Localization of myoglobin in mitochondria: implication in regulation of mitochondrial respiration in rat skeletal muscle. Physiol Rep 2021; 9:e14769. [PMID: 33650803 PMCID: PMC7923563 DOI: 10.14814/phy2.14769] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/01/2021] [Indexed: 11/24/2022] Open
Abstract
Mitochondria play a principal role in metabolism, and mitochondrial respiration is an important process for producing adenosine triphosphate. Recently, we showed the possibility that the muscle-specific protein myoglobin (Mb) interacts with mitochondrial complex IV to augment the respiration capacity in skeletal muscles. However, the precise mechanism for the Mb-mediated upregulation remains under debate. The aim of this study was to ascertain whether Mb is truly integrated into the mitochondria of skeletal muscle and to investigate the submitochondrial localization. Isolated mitochondria from rat gastrocnemius muscle were subjected to different proteinase K (PK) concentrations to digest proteins interacting with the outer membrane. Western blotting analysis revealed that the PK digested translocase of outer mitochondrial membrane 20 (Tom20), and the immunoreactivity of Tom20 decreased with the amount of PK used. However, the immunoreactivity of Mb with PK treatment was better preserved, indicating that Mb is integrated into the mitochondria of skeletal muscle. The mitochondrial protease protection assay experiments suggested that Mb localizes within the mitochondria in the inner membrane from the intermembrane space side. These results strongly suggest that Mb inside muscle mitochondria could be implicated in the regulation of mitochondrial respiration via complex IV.
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Affiliation(s)
- Rikuhide Koma
- Graduate School of Human and Socio‐Environmental StudiesKanazawa UniversityIshikawaJapan
| | | | | | - Toshihiko Oka
- Department of Life ScienceRikkyo UniversityTokyoJapan
| | - Thomas Jue
- Department of Biochemistry and Molecular MedicineUniversity of California DavisDavisCAUSA
| | - Hisashi Takakura
- Faculty of Health and Sports ScienceDoshisha UniversityKyotoJapan
| | - Kazumi Masuda
- Graduate School of Human and Socio‐Environmental StudiesKanazawa UniversityIshikawaJapan
- Faculty of Human SciencesKanazawa UniversityIshikawaJapan
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4
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Yang Y, Kong F, Li M, Fan J, Qiu T. Interaction between indium tin oxide nanoparticles and ferricytochrome c: Conformation, redox state, and adsorption scheme. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 213:64-72. [PMID: 30682648 DOI: 10.1016/j.saa.2019.01.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 12/25/2018] [Accepted: 01/15/2019] [Indexed: 06/09/2023]
Abstract
The conformations and redox states of ferricytochrome c, before and after adsorption onto the surface of the indium tin oxide (ITO) nanoparticles, are studied to reveal the interaction nature between the cytochrome c and the conducting metal oxide surface. The characterizations with resonance Raman scattering and UV-Vis absorption reveal that the change of pH at moderate ionic strength induces transitions of conformations and redox-states, which suggests that there is intramolecular electron transfer. The conformations of the cytochrome c species are maintained after adsorption onto or collision with the ITO surface, but the redox states change significantly, and the change depends on the surface structure of the ITO nanoparticle. The adsorption or collision processes are governed by the pH-dependent electrostatic interaction between the proteins and the buffer anions bound to the ITO surface. This adsorption scenario differs from the conventional ones.
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Affiliation(s)
- Yimin Yang
- School of Physics, Southeast University, Nanjing 211189, People's Republic of China.
| | - Fan Kong
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Mingze Li
- School of Physics, Southeast University, Nanjing 211189, People's Republic of China
| | - Jiyang Fan
- School of Physics, Southeast University, Nanjing 211189, People's Republic of China
| | - Teng Qiu
- School of Physics, Southeast University, Nanjing 211189, People's Republic of China.
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Melby ES, Allen C, Foreman-Ortiz IU, Caudill ER, Kuech TR, Vartanian AM, Zhang X, Murphy CJ, Hernandez R, Pedersen JA. Peripheral Membrane Proteins Facilitate Nanoparticle Binding at Lipid Bilayer Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10793-10805. [PMID: 30102857 DOI: 10.1021/acs.langmuir.8b02060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Molecular understanding of the impact of nanomaterials on cell membranes is critical for the prediction of effects that span environmental exposures to nanoenabled therapies. Experimental and computational studies employing phospholipid bilayers as model systems for membranes have yielded important insights but lack the biomolecular complexity of actual membranes. Here, we increase model membrane complexity by incorporating the peripheral membrane protein cytochrome c and studying the interactions of the resulting membrane systems with two types of anionic nanoparticles. Experimental and computational studies reveal that the extent of cytochrome c binding to supported lipid bilayers depends on anionic phospholipid number density and headgroup chemistry. Gold nanoparticles functionalized with short, anionic ligands or wrapped with an anionic polymer do not interact with silica-supported bilayers composed solely of phospholipids. Strikingly, when cytochrome c was bound to these bilayers, nanoparticles functionalized with short anionic ligands attached to model biomembranes in amounts proportional to the number of bound cytochrome c molecules. In contrast, anionic polymer-wrapped gold nanoparticles appeared to remove cytochrome c from supported lipid bilayers in a manner inversely proportional to the strength of cytochrome c binding to the bilayer; this reflects the removal of a weakly bound pool of cytochrome c, as suggested by molecular dynamics simulations. These results highlight the importance of the surface chemistry of both the nanoparticle and the membrane in predicting nano-bio interactions.
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Affiliation(s)
- Eric S Melby
- Environmental Chemistry and Technology Program , University of Wisconsin-Madison , 1525 Observatory Drive , Madison , Wisconsin 53706 , United States
- Environmental and Molecular Sciences Laboratory , Pacific Northwest National Laboratory , 3335 Innovation Boulevard , Richland , Washington 99354 , United States
| | - Caley Allen
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Isabel U Foreman-Ortiz
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Emily R Caudill
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Thomas R Kuech
- Environmental Chemistry and Technology Program , University of Wisconsin-Madison , 1525 Observatory Drive , Madison , Wisconsin 53706 , United States
| | - Ariane M Vartanian
- Department of Chemistry , University of Illinois at Urbana-Champaign , 600 South Mathews Avenue , Urbana , Illinois 61801 , United States
| | - Xi Zhang
- Department of Chemistry , University of Illinois at Urbana-Champaign , 600 South Mathews Avenue , Urbana , Illinois 61801 , United States
| | - Catherine J Murphy
- Department of Chemistry , University of Illinois at Urbana-Champaign , 600 South Mathews Avenue , Urbana , Illinois 61801 , United States
| | - Rigoberto Hernandez
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Joel A Pedersen
- Environmental Chemistry and Technology Program , University of Wisconsin-Madison , 1525 Observatory Drive , Madison , Wisconsin 53706 , United States
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
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Schweitzer-Stenner R. Relating the multi-functionality of cytochrome c to membrane binding and structural conversion. Biophys Rev 2018; 10:1151-1185. [PMID: 29574621 PMCID: PMC6082307 DOI: 10.1007/s12551-018-0409-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 02/23/2018] [Indexed: 12/16/2022] Open
Abstract
Cytochrome c is known as an electron-carrying protein in the respiratory chain of mitochondria. Over the last 20 years, however, alternative functions of this very versatile protein have become the focus of research interests. Upon binding to anionic lipids such as cardiolipin, the protein acquires peroxidase activity. Multiple lines of evidence suggest that this requires a conformational change of the protein which involves partial unfolding of its tertiary structure. This review summarizes the current state of knowledge of how cytochrome c interacts with cardiolipin-containing surfaces and how this affects its structure and function. In this context, we delineate partially conflicting results regarding the affinity of cytochrome c binding to cardiolipin-containing liposomes of different size and its influence on the structure of the protein and the morphology of the membrane.
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7
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Probing the extended lipid anchorage with cytochrome c and liposomes containing diacylphosphatidylglycerol lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1187-1192. [PMID: 29432713 DOI: 10.1016/j.bbamem.2018.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 02/01/2018] [Accepted: 02/08/2018] [Indexed: 11/21/2022]
Abstract
Experiments investigating the adsorption and desorption of cytochrome c onto and from liposomes containing 50 mol% 1,2-diacylphosphatidylglycerol lipids [10:0, 12:0, 14:0, 16:0, 18:1(Δ9 cis)] with 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) in pH 7.4 buffered solutions of low to moderate ionic strength are reported. Fluorescence experiments show that cytochrome c has a similar adsorption affinity for the five labeled 50 mol% PG liposome systems investigated. Fluorescence recovery experiments reveal the extent of cytochrome c desorption upon the addition of >10× excess of unlabeled 100% 1,2-dioleoyl-sn-glycero-3-phosphatidylglycerol (DOPG) liposomes is dependent on the lipid's acyl chain length. The extent of desorption is also shown to be independent of temperature, albeit over a narrow range. The differences in the extent of cytochrome c desorption from liposomes containing PG lipids with different acyl chain lengths is attributed to the varying contribution of the binding motif involving the extended lipid anchorage in response to lipid packing stress.
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Djafarzadeh S, Jakob SM. High-resolution Respirometry to Assess Mitochondrial Function in Permeabilized and Intact Cells. J Vis Exp 2017. [PMID: 28287504 DOI: 10.3791/54985] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
A high-resolution oxygraph is a device for measuring cellular oxygen consumption in a closed-chamber system with very high resolution and sensitivity in biological samples (intact and permeabilized cells, tissues or isolated mitochondria). The high-resolution oxygraph device is equipped with two chambers and uses polarographic oxygen sensors to measure oxygen concentration and calculate oxygen consumption within each chamber. Oxygen consumption rates are calculated using software and expressed as picomoles per second per number of cells. Each high-resolution oxygraph chamber contains a stopper with injection ports, which makes it ideal for substrate-uncoupler-inhibitor titrations or detergent titration protocols for determining effective and optimum concentrations for plasma membrane permeabilization. The technique can be applied to measure respiration in a wide range of cell types and also provides information on mitochondrial quality and integrity, and maximal mitochondrial respiratory electron transport system capacity.
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Affiliation(s)
- Siamak Djafarzadeh
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern;
| | - Stephan M Jakob
- Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern
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Cheniour M, Brewer J, Bagatolli L, Marcillat O, Granjon T. Evidence of proteolipid domain formation in an inner mitochondrial membrane mimicking model. Biochim Biophys Acta Gen Subj 2017; 1861:969-976. [PMID: 28185927 DOI: 10.1016/j.bbagen.2017.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/29/2017] [Accepted: 02/01/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND Mitochondrial creatine kinase (mtCK) is highly abundant in mitochondria; its quantity is equimolecular to the Adenylic Nucleotide Translocator and represents 1% of the mitochondrial proteins. It is a multitask protein localized in the mitochondria intermembrane space where it binds to the specific cardiolipin (CL) phospholipid. If mtCK was initially thought to be exclusively implicated in energy transfer between mitochondria and cytosol through a mechanism referred to as the phosphocreatine shuttle, several recent studies suggested an additional role in maintaining mitochondria membrane structure. METHODS To further characterized mtCK binding process we used multiphoton excitation fluorescence microscopy coupled with Giant Unilamellar Vesicles (GUV) and laurdan as fluorescence probe. RESULTS We gathered structural and dynamical information on the molecular events occurring during the binding of mtCK to the mitochondria inner membrane. We present the first visualization of mtCK-induced CL segregation on a bilayer model forming micrometer-size proteolipid domains at the surface of the GUV. Those microdomains, which only occurred when CL is included in the lipid mixture, were accompanied by the formation of protein multimolecular assembly, vesicle clamping, and changes in both vesicle curvature and membrane fluidity CONCLUSION: Those results highlighted the importance of the highly abundant mtCK in the lateral organization of the mitochondrial inner membrane. GENERAL SIGNIFICANCE Microdomains were induced in mitochondria-mimicking membranes composed of natural phospholipids without cholesterol and/or sphingolipids differing from the proposed cytoplasmic membrane rafts. Those findings as well as membrane curvature modification were discussed in relation with protein-membrane interaction and protein cluster involvement in membrane morphology.
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Affiliation(s)
- Mouhedine Cheniour
- Univ Lyon, Université Claude Bernard Lyon 1, ICBMS - UMR CNRS 5246, MEM2, F-69622 Villeurbanne, France
| | - Jonathan Brewer
- Membrane Biophysics and Biophotonics group/MEMPHYS Dept. Biochemistry and Molecular Biology, University of Southern, Denmark
| | - Luis Bagatolli
- Membrane Biophysics and Biophotonics group/MEMPHYS Dept. Biochemistry and Molecular Biology, University of Southern, Denmark
| | - Olivier Marcillat
- Univ Lyon, Université Claude Bernard Lyon 1, Centre de Recherche en Cancérologie de Lyon, F- 69373 Lyon, France
| | - Thierry Granjon
- Univ Lyon, Université Claude Bernard Lyon 1, ICBMS - UMR CNRS 5246, MEM2, F-69622 Villeurbanne, France.
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Serpas L, Milorey B, Pandiscia LA, Addison AW, Schweitzer-Stenner R. Autoxidation of Reduced Horse Heart Cytochrome c Catalyzed by Cardiolipin-Containing Membranes. J Phys Chem B 2016; 120:12219-12231. [PMID: 27934230 DOI: 10.1021/acs.jpcb.6b05620] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Visible circular dichroism, absorption, and fluorescence spectroscopy were used to probe the binding of horse heart ferrocytochrome c to anionic cardiolipin (CL) head groups on the surface of 1,1',2,2'-tetraoleoyl cardiolipin (TOCL)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) (20%:80%) liposomes in an aerobic environment. We found that ferrocytochrome c undergoes a conformational transition upon binding that leads to complete oxidation of the protein at intermediate and high CL concentrations. At low lipid concentrations, the protein maintains a structure that is only slightly different from its native one, whereas an ensemble of misligated predominantly hexacoordinated low-spin states become increasingly populated at high lipid concentrations. A minor fraction of conformations with either high- or quantum-mixed-spin states were detected at a CL to protein ratio of 200 (the largest one investigated). The population of the non-native state is less pronounced than that found for cytochrome c-CL interactions initiated with oxidized cytochrome c. Under anaerobic conditions, the protein maintains its reduced state but still undergoes some conformational change upon binding to CL head groups on the liposome surface. Our data suggest that CL-containing liposomes function as catalysts by reducing the activation barrier for a Fe2+ → O2 electron transfer. Adding NaCl to the existing cytochrome-liposome mixtures under aerobic conditions inhibits protein autoxidation of ferrocytochrome c and stabilizes the reduced state of the membrane-bound protein.
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Affiliation(s)
- Lee Serpas
- Department of Chemistry, Drexel University , 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Bridget Milorey
- Department of Chemistry, Drexel University , 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Leah A Pandiscia
- Department of Chemistry, Drexel University , 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Anthony W Addison
- Department of Chemistry, Drexel University , 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Reinhard Schweitzer-Stenner
- Department of Chemistry, Drexel University , 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States
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11
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Haldar S, Sil P, Thangamuniyandi M, Chattopadhyay K. Conversion of amyloid fibrils of cytochrome c to mature nanorods through a honeycomb morphology. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4213-23. [PMID: 25338286 DOI: 10.1021/la5029993] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Amyloid species with various morphologies have been found for different proteins and disease systems. In this article, we aim to ask if these morphologies are unique to a particular protein or if they convert from one to another. Using a heme protein containing iron as the transition-metal activator of aggregation and a negatively charged surfactant, partial unfolding of the protein and its aggregation have been induced. In the pathway of aggregation, we have observed the formation of several morphological structures of a single protein, which were visualized directly using atomic force microscopy (AFM). These structures have been found to appear and disappear with time, and their formation could be monitored under normal buffer conditions and at room temperature without requiring any sophisticated chemical or biological methodologies. In addition, we have observed the formation of honeycomb-shaped morphology, which may serve as an intermediate. These amyloid-based nanostructures may have the potential to be explored in therapeutics delivery and other biomedical applications.
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Affiliation(s)
- Shubhasis Haldar
- Protein Folding and Dynamics Laboratory, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, India
| | - Pallabi Sil
- Protein Folding and Dynamics Laboratory, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, India
| | - Muruganandan Thangamuniyandi
- Protein Folding and Dynamics Laboratory, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, India
| | - Krishnananda Chattopadhyay
- Protein Folding and Dynamics Laboratory, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Kolkata 700032, India
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Messaoud NB, Yue J, Valent D, Katzarova I, López JM. Osmostress-induced apoptosis in Xenopus oocytes: role of stress protein kinases, calpains and Smac/DIABLO. PLoS One 2015; 10:e0124482. [PMID: 25866890 PMCID: PMC4395108 DOI: 10.1371/journal.pone.0124482] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 03/02/2015] [Indexed: 12/22/2022] Open
Abstract
Hyperosmotic shock induces cytochrome c release and caspase-3 activation in Xenopus oocytes, but the regulators and signaling pathways involved are not well characterized. Here we show that hyperosmotic shock induces rapid calpain activation and high levels of Smac/DIABLO release from the mitochondria before significant amounts of cytochrome c are released to promote caspase-3 activation. Calpain inhibitors or EGTA microinjection delays osmostress-induced apoptosis, and blockage of Smac/DIABLO with antibodies markedly reduces cytochrome c release and caspase-3 activation. Hyperosmotic shock also activates the p38 and JNK signaling pathways very quickly. Simultaneous inhibition of both p38 and JNK pathways reduces osmostress-induced apoptosis, while sustained activation of these kinases accelerates the release of cytochrome c and caspase-3 activation. Therefore, at least four different pathways early induced by osmostress converge on the mitochondria to trigger apoptosis. Deciphering the mechanisms of hyperosmotic shock-induced apoptosis gives insight for potential treatments of human diseases that are caused by perturbations in fluid osmolarity.
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Affiliation(s)
- Nabil Ben Messaoud
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica, Facultad de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Jicheng Yue
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica, Facultad de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Daniel Valent
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica, Facultad de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Ilina Katzarova
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica, Facultad de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - José M. López
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica, Facultad de Medicina, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
- * E-mail:
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13
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Pandiscia LA, Schweitzer-Stenner R. Coexistence of Native-like and Non-Native Partially Unfolded Ferricytochrome c on the Surface of Cardiolipin-Containing Liposomes. J Phys Chem B 2015; 119:1334-49. [DOI: 10.1021/jp5104752] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Leah A. Pandiscia
- Department
of Chemistry, Drexel University, Philadelphia, PA 19104, United States
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14
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Muhsain SNF, Lang MA, Abu-Bakar A. Mitochondrial targeting of bilirubin regulatory enzymes: An adaptive response to oxidative stress. Toxicol Appl Pharmacol 2015; 282:77-89. [DOI: 10.1016/j.taap.2014.11.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/15/2014] [Accepted: 11/21/2014] [Indexed: 12/20/2022]
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15
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Bharmoria P, Trivedi TJ, Pabbathi A, Samanta A, Kumar A. Ionic liquid-induced all-α to α + β conformational transition in cytochrome c with improved peroxidase activity in aqueous medium. Phys Chem Chem Phys 2015; 17:10189-99. [DOI: 10.1039/c4cp06044j] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Choline dioctylsulfosuccinate [Cho][AOT] (a surface active ionic liquid) has been found to induce all-α to α + β conformational transition in the secondary structure of enzyme cytochrome c (Cyt c) with an enhanced peroxidase activity in its aqueous vesicular phase at pH 7.0.
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Affiliation(s)
- Pankaj Bharmoria
- Academy of Scientific and Innovative research (AcSIR)
- Central Salt and Marine Chemicals Research Institute
- Council of Scientific and Industrial Research (CSIR)
- Bhavnagar-364002
- India
| | - Tushar J. Trivedi
- Graduate School of EEWS (Energy Environment Water Sustainability)
- KAIST
- Daejeon 305-701
- Republic of Korea
| | - Ashok Pabbathi
- School of Chemistry
- University of Hyderabad
- Hyderabad 500 046
- India
| | - Anunay Samanta
- School of Chemistry
- University of Hyderabad
- Hyderabad 500 046
- India
| | - Arvind Kumar
- Academy of Scientific and Innovative research (AcSIR)
- Central Salt and Marine Chemicals Research Institute
- Council of Scientific and Industrial Research (CSIR)
- Bhavnagar-364002
- India
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16
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Pandiscia LA, Schweitzer-Stenner R. Salt as a catalyst in the mitochondria: returning cytochrome c to its native state after it misfolds on the surface of cardiolipin containing membranes. Chem Commun (Camb) 2014; 50:3674-6. [PMID: 24394851 DOI: 10.1039/c3cc48709a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cytochrome c binding to cardiolipin receptors on the surface of TOCL/DOPC(20% : 80%) liposomes induces a conformational change, which is not reversible after the protein's dissociation at low ionic strength. Addition of 100 mM NaCl switches the protein back to its native state.
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Affiliation(s)
- Leah A Pandiscia
- Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, PA, USA.
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17
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Cytochrome c: A Multifunctional Protein Combining Conformational Rigidity with Flexibility. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/484538] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cytochrome has served as a model system for studying redox reactions, protein folding, and more recently peroxidase activity induced by partial unfolding on membranes. This review illuminates some important aspects of the research on this biomolecule. The first part summarizes the results of structural analyses of its active site. Owing to heme-protein interactions the heme group is subject to both in-plane and out-of-plane deformations. The unfolding of the protein as discussed in detail in the second part of this review can be induced by changes of pH and temperature and most prominently by the addition of denaturing agents. Both the kinetic and thermodynamic folding and unfolding involve intermediate states with regard to all unfolding conditions. If allowed to sit at alkaline pH (11.5) for a week, the protein does not return to its folding state when the solvent is switched back to neutral pH. It rather adopts a misfolded state that is prone to aggregation via domain swapping. On the surface of cardiolipin containing liposomes, the protein can adopt a variety of partially unfolded states. Apparently, ferricytochrome c can perform biological functions even if it is only partially folded.
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Mohn ES, Lee JM, Beaver C, Tobbe G, McCarthy SM, O’Neil E, Smith BD, Breen JJ. Interactions of Cytochrome c with N-Acylated Phosphatidylethanolamine Lipids. J Phys Chem A 2014; 118:8287-92. [DOI: 10.1021/jp502063e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Emily S. Mohn
- Department
of Chemistry and Biochemistry, Providence College, Providence, Rhode Island 02918, United States
| | - Jung-Min Lee
- Department
of Chemistry and Biochemistry, Providence College, Providence, Rhode Island 02918, United States
| | - Christopher Beaver
- Department
of Chemistry and Biochemistry, Providence College, Providence, Rhode Island 02918, United States
| | - Gerri Tobbe
- Department
of Chemistry and Biochemistry, Providence College, Providence, Rhode Island 02918, United States
| | - Sean M. McCarthy
- Department
of Chemistry and Biochemistry, Providence College, Providence, Rhode Island 02918, United States
| | - Edward O’Neil
- Department
of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
| | - Bradley D. Smith
- Department
of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670, United States
| | - John J. Breen
- Department
of Chemistry and Biochemistry, Providence College, Providence, Rhode Island 02918, United States
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19
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Zaidi S, Hassan MI, Islam A, Ahmad F. The role of key residues in structure, function, and stability of cytochrome-c. Cell Mol Life Sci 2014; 71:229-55. [PMID: 23615770 PMCID: PMC11113841 DOI: 10.1007/s00018-013-1341-1] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/05/2013] [Accepted: 04/08/2013] [Indexed: 02/06/2023]
Abstract
Cytochrome-c (cyt-c), a multi-functional protein, plays a significant role in the electron transport chain, and thus is indispensable in the energy-production process. Besides being an important component in apoptosis, it detoxifies reactive oxygen species. Two hundred and eighty-five complete amino acid sequences of cyt-c from different species are known. Sequence analysis suggests that the number of amino acid residues in most mitochondrial cyts-c is in the range 104 ± 10, and amino acid residues at only few positions are highly conserved throughout evolution. These highly conserved residues are Cys14, Cys17, His18, Gly29, Pro30, Gly41, Asn52, Trp59, Tyr67, Leu68, Pro71, Pro76, Thr78, Met80, and Phe82. These are also known as "key residues", which contribute significantly to the structure, function, folding, and stability of cyt-c. The three-dimensional structure of cyt-c from ten eukaryotic species have been determined using X-ray diffraction studies. Structure analysis suggests that the tertiary structure of cyt-c is almost preserved along the evolutionary scale. Furthermore, residues of N/C-terminal helices Gly6, Phe10, Leu94, and Tyr97 interact with each other in a specific manner, forming an evolutionary conserved interface. To understand the role of evolutionary conserved residues on structure, stability, and function, numerous studies have been performed in which these residues were substituted with different amino acids. In these studies, structure deals with the effect of mutation on secondary and tertiary structure measured by spectroscopic techniques; stability deals with the effect of mutation on T m (midpoint of heat denaturation), ∆G D (Gibbs free energy change on denaturation) and folding; and function deals with the effect of mutation on electron transport, apoptosis, cell growth, and protein expression. In this review, we have compiled all these studies at one place. This compilation will be useful to biochemists and biophysicists interested in understanding the importance of conservation of certain residues throughout the evolution in preserving the structure, function, and stability in proteins.
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Affiliation(s)
- Sobia Zaidi
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025 India
| | - Md. Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025 India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025 India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025 India
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20
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Fülöp L, Rajki A, Katona D, Szanda G, Spät A. Extramitochondrial OPA1 and adrenocortical function. Mol Cell Endocrinol 2013; 381:70-9. [PMID: 23906536 DOI: 10.1016/j.mce.2013.07.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 07/19/2013] [Accepted: 07/19/2013] [Indexed: 02/06/2023]
Abstract
We have previously described that silencing of the mitochondrial protein OPA1 enhances mitochondrial Ca(2+) signaling and aldosterone production in H295R adrenocortical cells. Since extramitochondrial OPA1 (emOPA1) was reported to facilitate cAMP-induced lipolysis, we hypothesized that emOPA1, via the enhanced hydrolysis of cholesterol esters, augments aldosterone production in H295R cells. A few OPA1 immunopositive spots were detected in ∼40% of the cells. In cell fractionation studies OPA1/COX IV (mitochondrial marker) ratio in the post-mitochondrial fractions was an order of magnitude higher than that in the mitochondrial fraction. The ratio of long to short OPA1 isoforms was lower in post-mitochondrial than in mitochondrial fractions. Knockdown of OPA1 failed to reduce db-cAMP-induced phosphorylation of hormone-sensitive lipase (HSL), Ca(2+) signaling and aldosterone secretion. In conclusion, OPA1 could be detected in the post-mitochondrial fractions, nevertheless, OPA1 did not interfere with the cAMP - PKA - HSL mediated activation of aldosterone secretion.
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Affiliation(s)
- László Fülöp
- Department of Physiology, Faculty of Medicine, Semmelweis University, Hungary
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21
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Vladimirov YA, Proskurnina EV, Alekseev AV. Molecular mechanisms of apoptosis. Structure of cytochrome c-cardiolipin complex. BIOCHEMISTRY (MOSCOW) 2013; 78:1086-97. [DOI: 10.1134/s0006297913100027] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Masone D, Aloia FC, Del Pópolo MG. H-bond refinement for electron transfer membrane-bound protein-protein complexes: cytochrome c oxidase and cytochrome c552. Comput Biol Chem 2013; 47:31-6. [PMID: 23872047 DOI: 10.1016/j.compbiolchem.2013.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/29/2013] [Accepted: 05/30/2013] [Indexed: 11/19/2022]
Abstract
In this study we propose a protocol to evaluate membrane-bound cytochrome c oxidase-cytochrome c552 docking candidates. An initial rigid docking algorithm generates docking poses of the cytochrome c oxidase-cytochrome c552, candidates are then aggregated into a 512-DPPC membrane model and solvated in explicit solvent. Molecular dynamic simulations are performed to induce conformational changes to membrane-bound protein complexes. Lastly each protein-protein complex is optimized in terms of its hydrogen bond network, evaluated energetically and ranked. The protocol is directly applicable to other membrane-protein complexes, such as protein-ligand systems.
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Affiliation(s)
- Diego Masone
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Ciencias Básicas (ICB), Universidad Nacional de Cuyo (UNCUYO), Argentina.
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Brown MC, Mutter A, Koder RL, JiJi RD, Cooley JW. Observation of persistent α-helical content and discrete types of backbone disorder during a molten globule to ordered peptide transition via deep-UV resonance Raman spectroscopy. JOURNAL OF RAMAN SPECTROSCOPY : JRS 2013; 44:957-962. [PMID: 27795611 PMCID: PMC5082991 DOI: 10.1002/jrs.4316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The molten globule state can aide in the folding of a protein to a functional structure and is loosely defined as an increase in structural disorder with conservation of the ensemble secondary structure content. Simultaneous observation of persistent secondary structure content with increased disorder has remained experimentally problematic. As a consequence, modeling how the molten globule state remains stable and how it facilitates proper folding remains difficult due to a lack of amenable spectroscopic techniques to characterize this class of partially unfolded proteins. Previously, deep-UV resonance Raman (dUVRR) spectroscopy has proven useful in the resolution of global and local structural fluctuations in the secondary structure of proteins. In this work, dUVRR was employed to study the molten globule to ordered transition of a model four-helix bundle protein, HP7. Both the average ensemble secondary structure and types of local disorder were monitored, without perturbation of the solvent, pH, or temperature. The molten globule to ordered transition is induced by stepwise coordination of two heme molecules. Persistent dUVRR spectral features in the amide III region at 1295-1301 and 1335-1338 cm-1 confirm previous observations that HP7 remains predominantly helical in the molten globule versus the fully ordered state. Additionally, these spectra represent the first demonstration of conserved helical content in a molten globule protein. With successive heme binding significant losses are observed in the spectral intensity of the amide III3 and S regions (1230-1260 and 1390 cm-1, respectively), which are known to be sensitive to local disorder. These observations indicate that there is a decrease in the structural populations able to explore various extended conformations, with successive heme binding events. DUVRR spectra indicate that the first heme coordination between two helical segments diminishes exploration of more elongated backbone structural conformations in the inter-helical regions. A second heme coordination by the remaining two helices further restricts protein motion.
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Affiliation(s)
- Mia C. Brown
- Department of Chemistry, University of Missouri, Columbia, MO 65211
| | - Andrew Mutter
- Department of Physics, The City College of New York, New York, NY 10031
| | - Ronald L. Koder
- Department of Physics, The City College of New York, New York, NY 10031
| | - Renee D. JiJi
- Department of Chemistry, University of Missouri, Columbia, MO 65211
| | - Jason W. Cooley
- Department of Chemistry, University of Missouri, Columbia, MO 65211
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Elucidating the mechanism of ferrocytochrome c heme disruption by peroxidized cardiolipin. J Biol Inorg Chem 2012; 18:137-44. [PMID: 23160757 DOI: 10.1007/s00775-012-0958-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 11/01/2012] [Indexed: 10/27/2022]
Abstract
The interaction of peroxidized cardiolipin with ferrocytochrome c induces two kinetically and chemically distinct processes. The first is a rapid oxidation of ferrocytochrome c, followed by a slower, irreversible disruption of heme c. The oxidation of ferrocytochrome c by peroxidized cardiolipin is explained by a Fenton-type reaction. Heme scission is a consequence of the radical-mediated reactions initiated by the interaction of ferric heme iron with peroxidized cardiolipin. Simultaneously with the heme c disruption, generation of hydroxyl radical is detected by EPR spectroscopy using the spin trapping technique. The resulting apocytochrome c sediments as a heterogeneous mixture of high aggregates, as judged by sedimentation analysis. Both the oxidative process and the destructive process were suppressed by nonionic detergents and/or high ionic strength. The mechanism for generating radicals and heme rupture is presented.
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25
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Zhao HZ, Du Q, Li ZS, Yang QZ. Mechanisms for the direct electron transfer of cytochrome c induced by multi-walled carbon nanotubes. SENSORS 2012; 12:10450-62. [PMID: 23112609 PMCID: PMC3472837 DOI: 10.3390/s120810450] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 07/17/2012] [Accepted: 07/17/2012] [Indexed: 11/16/2022]
Abstract
Multi-walled carbon nanotube (MWCNT)-modified electrodes can promote the direct electron transfer (DET) of cytochrome c (Cyt c). There are several possible mechanisms that explain the DET of Cyt c. In this study, several experimental methods, including Fourier transform infrared spectroscopy, circular dichroism, ultraviolet-visible absorption spectroscopy, and electron paramagnetic resonance spectroscopy were utilized to investigate the conformational changes of Cyt c induced by MWCNTs. The DET mechanism was demonstrated at various nano-levels: secondary structure, spatial orientation, and spin state. In the presence of MWCNTs, the secondary structure of Cyt c changes, which exposes the active site, then, the orientation of the heme is optimized, revolving the exposed active center to the optimum spatial orientation for DET; and finally, a transition of spin states is induced, providing relatively high energy and a more open microenvironment for electron transfer. These changes at different nano-levels are closely connected and form a complex process that promotes the electron transfer of Cyt c.
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Affiliation(s)
- Hua-Zhang Zhao
- Department of Environmental Engineering, Peking University, Beijing 100871, China; E-Mails: (H.-Z.Z.); (Z.-S.L.)
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Qian Du
- School of Food and Bioengineering, Shandong Institute of Light Industry, Jinan 250353, China; E-Mail:
| | - Zhen-Shan Li
- Department of Environmental Engineering, Peking University, Beijing 100871, China; E-Mails: (H.-Z.Z.); (Z.-S.L.)
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Qin-Zheng Yang
- School of Food and Bioengineering, Shandong Institute of Light Industry, Jinan 250353, China; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel./Fax: +86-531-8801-1879
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26
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Kulikov AV, Shilov ES, Mufazalov IA, Gogvadze V, Nedospasov SA, Zhivotovsky B. Cytochrome c: the Achilles' heel in apoptosis. Cell Mol Life Sci 2012; 69:1787-97. [PMID: 22179840 PMCID: PMC11114681 DOI: 10.1007/s00018-011-0895-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 10/30/2011] [Accepted: 11/22/2011] [Indexed: 10/14/2022]
Abstract
Cytochrome c is a well-known mitochondrial protein that fulfills life-supporting functions by transferring electrons to the respiratory chain to maintain ATP production. However, during the activation of apoptotic machinery, it is released from mitochondria and, being in the cytosol, it either triggers the activation of the caspase cascade in intrinsic apoptotic pathway, or it is involved in the amplification of extrinsic apoptotic signaling. Accumulating evidence suggests that only unmodified holocytochrome c is efficient in the stimulation of apoptosis. Considering the importance of cytochrome c in both life and death, it was of significant interest to investigate the complete or partial cytochrome c deficiency in vivo. Here, we discuss the importance of distinct amino acid residues for various functions of cytochrome c in cells and mice with targeted cytochrome c mutations.
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Affiliation(s)
- A V Kulikov
- Faculty of Fundamental Medicine, Lomonosov Moscow State University, Moscow, Russia
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27
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Schug ZT, Frezza C, Galbraith LCA, Gottlieb E. The music of lipids: how lipid composition orchestrates cellular behaviour. Acta Oncol 2012; 51:301-10. [PMID: 22283492 DOI: 10.3109/0284186x.2011.643823] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Lipids are best known for their fundamental role in forming biological membranes and as intracellular signalling molecules. Interactions between proteins and lipids are central to nearly every cellular process yet these crucial relationships often go overlooked. Changes or switches in the lipid profile of a cell drastically affects cellular metabolism and signal transduction. In relationship to cancer, upregulation of lipid metabolism is often observed during the early stages of neoplasia and is a recognised hallmark of many types of cancer. METHODS We performed a comprehensive review of the literature using PubMed regarding lipid metabolism in cancer and the importance of protein-lipid interactions in the function of mitochondria. RESULTS An increase in the basal rate of de novo lipogenesis generates a substantial rise in the saturated fatty acid content of cellular membranes. The ensuing alteration in the acyl chain profile of phospholipids has severe consequences on the function of organelles and membrane-bound proteins, and result in a host of pathologies including the cardiac disorder Barth Syndrome. CONCLUSIONS Although increased lipogenesis is specifically selected for during cellular transformation it remains unclear if it confers an advantage for survival or is a byproduct of more global changes in cellular metabolism. We discuss the current data regarding the potential of targeting the lipogenic switch as a cancer therapy. In addition, we describe the importance of mitochondrial phospholipid composition during a number mitochondria-driven events observed to have roles in cancer. We specifically highlight the function of cardiolipin in maintaining mitochondrial structure, regulating mitochondrial dynamics and bioenergetics as well as its contributions to mitophagy/autophagy and apoptosis.
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Affiliation(s)
- Zachary T Schug
- Laboratory of Apoptosis and Tumour Metabolism, Cancer Research UK, The Beatson Institute for Cancer Research, Glasgow G61 1BD, UK
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Beales PA, Bergstrom CL, Geerts N, Groves JT, Vanderlick TK. Single vesicle observations of the cardiolipin-cytochrome C interaction: induction of membrane morphology changes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6107-15. [PMID: 21504165 PMCID: PMC3103708 DOI: 10.1021/la104924c] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We present a novel platform for investigating the composition-specific interactions of proteins (or other biologically relevant molecules) with model membranes composed of compositionally distinct domains. We focus on the interaction between a mitochondrial-specific lipid, cardiolipin (CL), and a peripheral membrane protein, cytochrome c (cyt c). We engineer vesicles with compositions such that they phase separate into coexisting liquid phases and the lipid of interest, CL, preferentially localizes into one of the domains (the liquid disordered (L(d)) phase). The presence of CL-rich and CL-depleted domains within the same vesicle provides a built-in control experiment to simultaneously observe the behavior of two membrane compositions under identical conditions. We find that cyt c binds strongly to CL-rich domains and observe fascinating morphological transitions within these regions of membrane. CL-rich domains start to form small buds and eventually fold up into a collapsed state. We also observe that cyt c can induce a strong attraction between the CL-rich domains of adjacent vesicles as demonstrated by the development of large osculating regions between these domains. Qualitatively similar behavior is observed when other polycationic proteins or polymers of a similar size and net charge are used instead of cyt c. We argue that these striking phenomena can be simply understood by consideration of colloidal forces between the protein and the membrane. We discuss the possible biological implications of our observations in relation to the structure and function of mitochondria.
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Affiliation(s)
- Paul A. Beales
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA
| | | | - Nienke Geerts
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA
| | - John T. Groves
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - T. Kyle Vanderlick
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA
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Otzen D. Protein–surfactant interactions: A tale of many states. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:562-91. [DOI: 10.1016/j.bbapap.2011.03.003] [Citation(s) in RCA: 362] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/23/2011] [Accepted: 03/04/2011] [Indexed: 10/18/2022]
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Morandat S, El Kirat K. Cytochrome c provokes the weakening of zwitterionic membranes as measured by force spectroscopy. Colloids Surf B Biointerfaces 2011; 82:111-7. [DOI: 10.1016/j.colsurfb.2010.08.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 08/16/2010] [Accepted: 08/18/2010] [Indexed: 11/29/2022]
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The non-native conformations of cytochrome c in sodium dodecyl sulfate and their modulation by ATP. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2010; 40:259-71. [PMID: 21116622 DOI: 10.1007/s00249-010-0643-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 10/16/2010] [Accepted: 11/10/2010] [Indexed: 10/18/2022]
Abstract
To understand the interaction of cytochrome c (cyt c) with membranes, a systematic investigation of sodium dodecyl sulfate (SDS)-induced conformational alterations in native horse heart ferricytochrome c (pH 7.0) was carried out using heme absorbance, tryptophan fluorescence and circular dichroism (CD) spectroscopy. ATP interaction with membrane-bound cyt c is known to regulate the process of apoptosis. To understand the effect of nucleotide phosphates on membrane-bound cyt c, we also carried out studies of the interaction of ATP with cyt c in the presence of SDS. Fluorescence and UV-Vis data suggest that SDS induces two different transitions (F to C1, C1 to C2) in cyt c, one in the pre-micellar region and the other in the post-micellar region. The fluorescence data further indicated the increase in distance between Trp 59 and heme in the intermediates in both the regions, suggesting loosening up of cyt c on titration with SDS. The far-UV and near-UV CD data suggest partial loss of secondary and tertiary structure in C1, but complete loss of tertiary structure and no further loss of secondary structure in C2. On titration of C1 and C2 with ATP, the secondary structure is restored. However, the heme ligation pattern and heme exposure change only for C2, but not for C1 on the addition of ATP.
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Abel S, Waks M, Marchi M. Molecular dynamics simulations of cytochrome c unfolding in AOT reverse micelles: The first steps. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2010; 32:399-409. [PMID: 20803162 DOI: 10.1140/epje/i2010-10635-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 07/06/2010] [Indexed: 05/29/2023]
Abstract
This paper explores the reduced form of horse cytochrome c confined in reverse micelles (RM) of sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) in isooctane by molecular dynamics simulation. RMs of two sizes were constructed at a water content of W (o) = [ H₂O ]/[AOT] = 5.5 and 9.1. Our results show that the protein secondary structure and the heme conformation both depend on micellar hydration. At low hydration, the protein structure and the heme moiety remain stable, whereas at high water content the protein becomes unstable and starts to unfold. At W (o) = 9.1 , according to the X-ray structure, conformational changes are mainly localized on protein loops and around the heme moiety, where we observe a partial opening of the heme crevice. These findings suggest that within our time window (10ns), the structural changes observed at the heme level are the first steps of the protein denaturation process, previously described experimentally in micellar solutions. In addition, a specific binding of AOT molecules to a few lysine residues of the protein was found only in the small-sized RM.
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Affiliation(s)
- S Abel
- DSV/iBiTecS/SB2SM, CNRS URA, Gif-sur-Yvette, France.
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Lenaz G, Genova ML. Structure and organization of mitochondrial respiratory complexes: a new understanding of an old subject. Antioxid Redox Signal 2010; 12:961-1008. [PMID: 19739941 DOI: 10.1089/ars.2009.2704] [Citation(s) in RCA: 186] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The enzymatic complexes of the mitochondrial respiratory chain have been extensively investigated in their structural and functional properties. A clear distinction is possible today between three complexes in which the difference in redox potential allows proton translocation (complexes I, III, and IV) and those having the mere function to convey electrons to the respiratory chain. We also have a clearer understanding of the structure and function of most respiratory complexes, of their biogenesis and regulation, and of their capacity to generate reactive oxygen species. Past investigations led to the conclusion that the complexes are randomly dispersed and functionally connected by diffusion of smaller redox components, coenzyme Q and cytochrome c. More-recent investigations by native gel electrophoresis and single-particle image processing showed the existence of supramolecular associations. Flux-control analysis demonstrated that complexes I and III in mammals and I, III, and IV in plants kinetically behave as single units, suggesting the existence of substrate channeling. This review discusses conditions affecting the formation of supercomplexes that, besides kinetic advantage, have a role in the stability and assembly of the individual complexes and in preventing excess oxygen radical formation. Disruption of supercomplex organization may lead to functional derangements responsible for pathologic changes.
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Affiliation(s)
- Giorgio Lenaz
- Dipartimento di Biochimica "G. Moruzzi," Alma Mater Studiorum, Università di Bologna, Bologna, Italy.
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El Kirat K, Morandat S, Dufrêne YF. Nanoscale analysis of supported lipid bilayers using atomic force microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:750-65. [DOI: 10.1016/j.bbamem.2009.07.026] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/17/2009] [Accepted: 07/23/2009] [Indexed: 12/11/2022]
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35
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Lenaz G, Genova ML. Structural and functional organization of the mitochondrial respiratory chain: a dynamic super-assembly. Int J Biochem Cell Biol 2009; 41:1750-1772. [PMID: 19711505 DOI: 10.1016/j.biocel.2009.04.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The structural organization of the mitochondrial oxidative phosphorylation (OXPHOS) system has received large attention in the past and most investigations led to the conclusion that the respiratory enzymatic complexes are randomly dispersed in the lipid bilayer of the inner membrane and functionally connected by fast diffusion of smaller redox components, Coenzyme Q and cytochrome c. More recent investigations by native gel electrophoresis, however, have shown the existence of supramolecular associations of the respiratory complexes, confirmed by electron microscopy analysis and single particle image processing. Flux control analysis has demonstrated that Complexes I and III in mammalian mitochondria and Complexes I, III, and IV in plant mitochondria kinetically behave as single units with control coefficients approaching unity for each single component, suggesting the existence of substrate channelling within the supercomplexes. The reasons why the presence of substrate channelling for Coenzyme Q and cytochrome c was overlooked in the past are analytically discussed. The review also discusses the forces and the conditions responsible for the formation of the supramolecular units. The function of the supercomplexes appears not to be restricted to kinetic advantages in electron transfer: we discuss evidence on their role in the stability and assembly of the individual complexes and in preventing excess oxygen radical formation. Finally, there is increasing evidence that disruption of the supercomplex organization leads to functional derangements responsible for pathological changes.
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Affiliation(s)
- Giorgio Lenaz
- Dipartimento di Biochimica G. Moruzzi, Università di Bologna, Via Irnerio 48, 40126 Bologna, Italy.
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36
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El Kirat K, Morandat S. Cytochrome c interaction with neutral lipid membranes: influence of lipid packing and protein charges. Chem Phys Lipids 2009; 162:17-24. [DOI: 10.1016/j.chemphyslip.2009.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 08/05/2009] [Accepted: 08/13/2009] [Indexed: 10/20/2022]
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37
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Verbaro D, Hagarman A, Soffer J, Schweitzer-Stenner R. The pH Dependence of the 695 nm Charge Transfer Band Reveals the Population of an Intermediate State of the Alkaline Transition of Ferricytochrome c at Low Ion Concentrations. Biochemistry 2009; 48:2990-6. [DOI: 10.1021/bi802208f] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Daniel Verbaro
- Department of Chemistry and Department of Biology, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104
| | - Andrew Hagarman
- Department of Chemistry and Department of Biology, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104
| | - Jonathan Soffer
- Department of Chemistry and Department of Biology, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104
| | - Reinhard Schweitzer-Stenner
- Department of Chemistry and Department of Biology, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104
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38
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Li T, Brustovetsky T, Antonsson B, Brustovetsky N. Oligomeric BAX induces mitochondrial permeability transition and complete cytochrome c release without oxidative stress. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1777:1409-21. [PMID: 18771651 PMCID: PMC2613194 DOI: 10.1016/j.bbabio.2008.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 08/07/2008] [Accepted: 08/08/2008] [Indexed: 01/26/2023]
Abstract
In the present study, we investigated the mechanism of cytochrome c release from isolated brain mitochondria induced by recombinant oligomeric BAX (BAX(oligo)). We found that BAX(oligo) caused a complete release of cytochrome c in a concentration- and time-dependent manner. The release was similar to those induced by alamethicin, which causes maximal mitochondrial swelling and eliminates barrier properties of the OMM. BAX(oligo) also produced large amplitude mitochondrial swelling as judged by light scattering assay and transmission electron microscopy. In addition, BAX(oligo) resulted in a strong mitochondrial depolarization. ATP or a combination of cyclosporin A and ADP, inhibitors of the mPT, suppressed BAX(oligo)-induced mitochondrial swelling and depolarization as well as cytochrome c release but did not influence BAX(oligo) insertion into the OMM. Both BAX(oligo)- and alamethicin-induced cytochrome c releases were accompanied by inhibition of ROS generation, which was assessed by measuring mitochondrial H(2)O(2) release with an Amplex Red assay. The mPT inhibitors antagonized suppression of ROS generation caused by BAX(oligo) but not by alamethicin. Thus, BAX(oligo) resulted in a complete cytochrome c release from isolated brain mitochondria in the mPT-dependent manner without involvement of oxidative stress by the mechanism requiring mitochondrial remodeling and permeabilization of the OMM.
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Affiliation(s)
- Tsyregma Li
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
| | - Bruno Antonsson
- Geneva Research Center, Merck Serono International, Geneva, Switzerland
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis IN 46202, USA
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis IN 46202, USA
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39
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Dadak V, Holik M. Electrostatic attraction between cytochrome bc 1 and cytochrome c affects kinetics of cytochrome c reduction. BIOCHEMISTRY (MOSCOW) 2008; 73:870-80. [DOI: 10.1134/s000629790808004x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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40
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Huang Z, Jiang J, Tyurin VA, Zhao Q, Mnuskin A, Ren J, Belikova NA, Feng W, Kurnikov IV, Kagan VE. Cardiolipin deficiency leads to decreased cardiolipin peroxidation and increased resistance of cells to apoptosis. Free Radic Biol Med 2008; 44:1935-44. [PMID: 18375209 PMCID: PMC2692820 DOI: 10.1016/j.freeradbiomed.2008.02.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/21/2008] [Accepted: 02/23/2008] [Indexed: 01/08/2023]
Abstract
Cardiolipin (CL), a unique mitochondrial phospholipid synthesized by CL synthase (CLS), plays important, yet not fully understood, roles in mitochondria-dependent apoptosis. We manipulated CL levels in HeLa cells by knocking down CLS using RNA interference and selected a clone of CL-deficient cells with approximately 45% of its normal content. ESI-MS analysis showed that the CL molecular species were the same in CL-deficient and CL-sufficient cells. CL deficiency did not change mitochondrial functions (membrane potential, reactive oxygen species generation, cellular ATP levels) but conferred resistance to apoptosis induced by actinomycin D (ActD), rotenone, or gamma-irradiation. During ActD-induced apoptosis, decreased CL peroxidation along with suppressed cytochrome (cyt) c release was observed in CL-deficient cells, whereas Bax translocation to mitochondria remained similar to that in CL-sufficient HeLa cells. The amounts of loosely bound cyt c (releasable under high ionic strength conditions) were the same in CL-deficient and CL-sufficient cells. Given that CL peroxidation during apoptosis is catalyzed by CL/cyt c complexes and CL oxidation products are essential for cyt c release from mitochondria, our results suggest that CL deficiency prevents adequate assembly of productive CL/cyt c complexes and CL peroxidation, resulting in increased resistance to apoptosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Valerian E. Kagan
- Address correspondence to: Valerian E. Kagan, Department of Environmental and Occupational Health, University of Pittsburgh, Bridgeside Point, 100 Technology Drive, Suite 350, Pittsburgh, PA 15219. Tel: 412-624-9479; Fax: 412-624-9361; E-mail:
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41
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The interaction of liver fatty-acid-binding protein (FABP) with anionic phospholipid vesicles: is there extended phospholipid anchorage under these conditions? Biochem J 2008; 410:123-9. [PMID: 17935485 DOI: 10.1042/bj20071109] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Liver FABP (fatty-acid-binding protein) binds a variety of non-polar anionic ligands including fatty acids, fatty acyl CoAs, lysophospholipids and bile acids. Liver FABP is also able to bind to anionic phospholipid vesicles under conditions of low ionic strength, and membrane binding results in the release of bound ligand. However, the molecular interactions involved in binding to the phospholipid interface and the mechanism of ligand release are not known. Ligand release could be due to a significant conformational change in the protein at the interface or interaction of a phospholipid molecule with the ligand-binding cavity of the protein resulting in ligand displacement. Two portal mutant proteins of liver FABP, L28W and M74W, have now been used to investigate the binding of liver FABP to anionic phospholipid vesicles, monitoring changes in fluorescence and also fluorescence quenching in the presence of brominated lipids. There is a large increase in fluorescence intensity when the L28W mutant protein binds to vesicles prepared from DOPG (dioleoyl-sn-phosphatidylglycerol), but a large decrease in fluorescence intensity when the M74W mutant binds to these vesicles. The Br(4)-phospholipid prepared by bromination of DOPG dramatically quenches both L28W and M74W, consistent with the close proximity of a fatty acyl chain to the tryptophan residues. The binding of liver FABP to DOPG vesicles is accompanied by only a minimal change in the CD spectrum. Overall, the results are consistent with a molecule of anionic phospholipid interacting with the central cavity of the liver FABP, possibly involving the phospholipid molecule in an extended conformation.
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42
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Jiang J, Huang Z, Zhao Q, Feng W, Belikova NA, Kagan VE. Interplay between bax, reactive oxygen species production, and cardiolipin oxidation during apoptosis. Biochem Biophys Res Commun 2008; 368:145-50. [PMID: 18211809 DOI: 10.1016/j.bbrc.2008.01.055] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Accepted: 01/15/2008] [Indexed: 11/16/2022]
Abstract
Bax/Bak activation and cardiolipin peroxidation are essential for cytochrome c release during apoptosis, yet, the link between them remains elusive. We report that sequence of events after exposure of mouse embryonic fibroblast (MEF) cells to actinomycin D followed the order: Bax translocation-->superoxide production-->cardiolipin peroxidation. Genetic ablation of Bax/Bak inhibited actinomycin D induced superoxide production and cardiolipin peroxidation. Rotenone caused robust superoxide generation but did not trigger cardiolipin peroxidation in Bax/Bak double knockout MEF cells. This suggests that, in addition to participating in ROS generation, Bax/Bak play another specific role in cardiolipin oxidation. In isolated mitochondria, recombinant Bax enhanced succinate induced cardiolipin oxidation and cytochrome c release. Mitochondrial peroxidase activity, likely involved in cardiolipin peroxidation, was enhanced upon incubation with recombinant Bax. Thus, cardiolipin peroxidation may be causatively and time-dependently related to Bax/Bak effects on ROS generation and peroxidase activation of cytochrome c.
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Affiliation(s)
- Jianfei Jiang
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh, Bridgeside Point, 100 Technology Drive, Suite 350, Pittsburgh, PA 15219, USA
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43
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Kalanxhi E, Wallace C. Cytochrome c impaled: investigation of the extended lipid anchorage of a soluble protein to mitochondrial membrane models. Biochem J 2008; 407:179-87. [PMID: 17614790 PMCID: PMC2049027 DOI: 10.1042/bj20070459] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cyt c (cytochrome c) has been traditionally envisioned as rapidly diffusing in two dimensions at the surface of the mitochondrial inner membrane when not engaged in redox reactions with physiological partners. However, the discovery of the extended lipid anchorage (insertion of an acyl chain of a bilayer phospholipid into the protein interior) suggests that this may not be exclusively the case. The physical and structural factors underlying the conformational changes that occur upon interaction of ferrous cyt c with phospholipid membrane models have been investigated by monitoring the extent of the spin state change that result from this interaction. Once transiently linked by electrostatic forces between basic side chains and phosphate groups, the acyl chain entry may occur between two parallel hydrophobic polypeptide stretches that are surrounded by positively charged residues. Alteration of these charges, as in the case of non-trimethylated (TML72K) yeast cyt c and Arg91Nle horse cyt c (where Nle is norleucine), led to a decline in the binding affinity for the phospholipid liposomes. The electrostatic association was sensitive to ionic strength, polyanions and pH, whereas the hydrophobic interactions were enhanced by conformational changes that contributed to the loosening of the tertiary structure of cyt c. In addition to proposing a mechanistic model for the extended lipid anchorage of cyt c, we consider what, if any, might be the physiological relevance of the phenomenon.
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Affiliation(s)
- Erta Kalanxhi
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada B3H1X5
| | - Carmichael J. A. Wallace
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada B3H1X5
- To whom correspondence should be addressed (email )
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44
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Marković D, Pröll S, Bubenzer C, Scheer H. Myoglobin with chlorophyllous chromophores: influence on protein stability. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:897-904. [PMID: 17490605 DOI: 10.1016/j.bbabio.2007.03.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 03/15/2007] [Accepted: 03/19/2007] [Indexed: 11/24/2022]
Abstract
The stabilities of myoglobin, apo-myoglobin, and of two myoglobins with chlorophyllous chromophores (Zn-pheophorbide a and Zn-bacteriopheophorbide a), have been studied by thermal and chemical denaturation. With guanidinium chloride, the stability order is myoglobin>Zn-pheophorbide-myoglobin>Zn-bacteriopheophorbide-myoglobin approximately apo-myoglobin. The thermal behavior is more complex. The transition temperature of thermal unfolding of the apoprotein (62.4 degrees C) is increased by Zn-pheophorbide a (83.9 degrees C) and Zn-bacteriopheophorbide a (82.6 degrees C) to a similar degree as by the native chromophore, heme (83.5 degrees C). The recovery with Zn-pheophorbide (92-98%) is even higher than with heme (74-76%), while with Zn-bacteriopheophorbide (40%) it is as low as with the apoprotein (42%). Recovery also depends on the rates of heating, and in particular the time spent at high temperatures. It is concluded that irreversibility of unfolding is related to loss of the chromophores, which are required for proper re-folding.
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Affiliation(s)
- Dejan Marković
- Department of Biologie I, Botanik, Menzinger Str. 67, D-80638 München, Germany
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45
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Buratta M, Piccotti L, Giannini S, Gresele P, Roberti R, Corazzi L. Selective Cytochrome c Displacement by Phosphate and Ca2+ in Brain Mitochondria. J Membr Biol 2007; 212:199-210. [PMID: 17334837 DOI: 10.1007/s00232-006-0015-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 06/11/2006] [Indexed: 10/23/2022]
Abstract
In brain mitochondria, phosphate- and Ca(2+)-dependent cytocrome c (cyt c) release reveals pools that interact differently with the inner membrane. Detachment of the phosphate-dependent pool did not influence the pool released by Ca(2+). Cyt c pools were also detected in a system of cyt c reconstituted in cardiolipin (CL) liposomes. Gradual binding of cyt c (1 nmol) to CL/2-[12-(7-nitrobenz- 2-oxa-1,3-diazol-4-yl)amino]dodecanoyl-1-hexadecan oyl-sn-glycero-3-phosphocholine (NBDC(12)-HPC) liposomes (10 nmol) produced NBD fluorescence quenching up to 0.4 nmol of added protein. Additional bound cyt c did not produce quenching, suggesting that cyt c-CL interactions originate distinct cyt c pools. Cyt c was removed from CL/NBDC(12)-HPC liposomes by either phosphate or Ca(2+), but only Ca(2+) produced fluorescence dequenching and leakage of encapsulated 8-aminonaphthalene-1,3,6-trisulfonic acid/p-xylene-bis-pyridinium bromide. In mitochondria, complex IV activity and mitochondrial membrane potential (Deltapsi(m)) were not affected by the release of the phosphate-dependent cyt c pool. Conversely, removal of cyt c by Ca(2+) caused inhibition of complex IV activity and impairment of Deltapsi(m). In a reconstituted system of mitochondria, nuclei and supernatant, cyt c detached from the inner membrane was released outside mitochondria and triggered events leading to DNA fragmentation. These events were prevented by enriching mitochondria with exogenous CL or by sequestering released cyt c with anti-cyt c antibody.
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Affiliation(s)
- Morena Buratta
- Laboratory of Biochemistry, Department of Internal Medicine, University of Perugia, Via del Giochetto, 06122, Perugia, Italy
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46
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La Penna G, Furlan S, Banci L. Molecular statistics of cytochrome c: structural plasticity and molecular environment. J Biol Inorg Chem 2006; 12:180-93. [PMID: 17053911 DOI: 10.1007/s00775-006-0178-6] [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: 06/22/2006] [Accepted: 09/19/2006] [Indexed: 10/24/2022]
Abstract
Nuclear magnetic resonance experiments performed on yeast mitochondrial cytochrome c (Cytc), a paradigmatic electron transfer protein, reveal that the two oxidation states have similar structures, but different mobility: despite the few structural differences compared with the reduced form, the oxidized form displays a larger unfolding propensity. Molecular dynamics simulations performed on both NMR reduced and NMR oxidized forms show that the reduced form has a larger solvent-accessible surface area (SASA). Starting from this observation, a molecular statistical approach was then applied in order to correlate the molecular surface to molecular mobility. Simulations started from biased initial conditions corresponding to different molecular sizes were combined with the maximal constrained entropy method. The NMR structure of oxidized Cytc is more suited to expose a smaller SASA than the NMR structure of the reduced form, but the accessible conformational landscape at 300 K around the NMR oxidized structure is flatter than for the NMR reduced structure. Protein configurations of smaller SASA and size display larger plasticity when they resemble the NMR oxidized structure, whereas they are more rigid when they resemble the NMR reduced structure. Implications of the results for the protein properties during its functional process are discussed.
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Affiliation(s)
- Giovanni La Penna
- Institute for Macromolecular Studies, National Research Council, Via De Marini 6, 16149, Genoa, Italy.
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47
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Gogvadze V, Orrenius S. Mitochondrial regulation of apoptotic cell death. Chem Biol Interact 2006; 163:4-14. [PMID: 16730343 DOI: 10.1016/j.cbi.2006.04.010] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 04/03/2006] [Accepted: 04/06/2006] [Indexed: 01/17/2023]
Abstract
Mitochondria play a decisive role in the regulation of both apoptotic and necrotic cell death. Permeabilization of the outer mitochondrial membrane and subsequent release of intermembrane space proteins are important features of both models of cell death. The mechanisms by which these proteins are released depend presumably on cell type and the nature of stimuli. Of the mechanisms involved, mitochondrial permeability transition appears to be associated mainly with necrosis, whereas the release of caspase activating proteins during early apoptosis is regulated primarily by the Bcl-2 family of proteins. However, there is increasing evidence for interaction and co-operation between these two mechanisms. The multiple mechanisms of mitochondrial permeabilization may explain diversities in the response of mitochondria to numerous apoptotic stimuli in different types of cells.
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Affiliation(s)
- Vladimir Gogvadze
- Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden
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48
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Liang L, Yao P, Jiang M. Reversibility of Structural Transition of Cytochrome c on Interacting with and Releasing from Alternating Copolymers of Maleic Acid and Alkene. Biomacromolecules 2006; 7:1829-35. [PMID: 16768404 DOI: 10.1021/bm060150n] [Citation(s) in RCA: 10] [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
The interaction of cytochrome c (cyt c) with poly(isobutylene-alt-maleic acid) (PIMA) and poly(1-tetradecene-alt-maleic acid) (PTMA) was studied using circular dichroism, absorption spectroscopy, and atomic force microscopy to investigate the electrostatic and hydrophobic influence of the copolymers on the structure of cyt c. At pH 7.4, the interaction of PIMA with cyt c can only partly disturb the integrity of the heme pocket, while PTMA has very intensive influence on the structure of cyt c. After adding 0.15 M NaCl, PIMA-cyt c complexes dissociate, and the released cyt c recovers its native structure, whereas NaCl has no significant influence on PTMA-cyt c complexes. GuHCl (0.5 M) destroys PTMA-cyt c complexes, forming GuHCl-PTMA precipitates; the cyt c released from the complexes regenerates its native structure. In comparison with electrostatic interaction, hydrophobic interaction leads to more stable polymer-cyt c complexes and more intensive influence on cyt c structure, but cyt c can recover its native state after release.
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Affiliation(s)
- Li Liang
- The Key Laboratory of Molecular Engineering of Polymer and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
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49
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Gorbenko GP, Molotkovsky JG, Kinnunen PKJ. Cytochrome C interaction with cardiolipin/phosphatidylcholine model membranes: effect of cardiolipin protonation. Biophys J 2006; 90:4093-103. [PMID: 16565064 PMCID: PMC1459516 DOI: 10.1529/biophysj.105.080150] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Resonance energy transfer between anthrylvinyl-labeled phosphatidylcholine as a donor and heme moiety of cytochrome c (cyt c) as an acceptor has been employed to explore the protein binding to model membranes, composed of phosphatidylcholine and cardiolipin (CL). The existence of two types of protein-lipid complexes has been hypothesized where either deprotonated or partially protonated CL molecules are responsible for cyt c attachment to bilayer surface. To quantitatively describe cyt c membrane binding, the adsorption model based on scaled particle and double layer theories has been employed, with potential-dependent association constants being treated as a function of acidic phospholipid mole fraction, degree of CL protonation, ionic strength, and surface coverage. Multiple arrays of resonance energy transfer data obtained under conditions of varying pH, ionic strength, CL content, and protein/lipid molar ratio have been analyzed in terms of the model of energy transfer in two-dimensional systems combined with the adsorption model allowing for area exclusion and electrostatic effects. The set of recovered model parameters included effective protein charge, intrinsic association constants, and heme distance from the bilayer midplane for both types of protein-lipid complexes. Upon increasing CL mole fraction from 10 to 20 mol % (the value close to that characteristic of the inner mitochondrial membrane), the binding equilibrium dramatically shifted toward cyt c association with partially protonated CL species. The estimates of heme distance from bilayer center suggest shallow bilayer location of cyt c at physiological pH, whereas at pH below 6.0, the protein tends to insert into membrane core.
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Affiliation(s)
- Galyna P Gorbenko
- Department of Biological and Medical Physics, V.N. Karazin Kharkiv National University, Kharkiv, Ukraine
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50
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Xu Q, Keiderling TA. Stop-flow kinetics studies of the interaction of surfactant, sodium dodecyl sulfate, with acid-denatured cytochrome c. Proteins 2006; 63:571-80. [PMID: 16586446 DOI: 10.1002/prot.20926] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Interactions of sodium dodecyl sulfate (SDS) at submicellar and micellar concentration, with the globular protein, horse heart cytochrome c, at low pH have been shown to stabilize two molten globule-like intermediates. These dynamic studies were performed using far-UV, near-UV, and Soret-band circular dichroism (CD) as well as fluorescence methods. Stopped-flow CD and fluorescence studies of acid-denatured cytochrome c refolding with SDS were performed at both submicellar and micellar concentrations. Distinctive refolding mechanisms (from analysis of both CD and fluorescence) were found under these two conditions, and an obvious refolding intermediate was evident in the fluorescence traces. In addition, stopped-flow CD in the Soret region showed multistep kinetics, suggesting that the spectral changes in this region are not only solvent effect related but also connected with the change of secondary structure. A possible folding mechanism is proposed to rationalize the kinetics results.
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Affiliation(s)
- Qi Xu
- Department of Chemistry, University of Illinois at Chicago, 60607-7061, USA
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