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Sedlák E, Žár T, Varhač R, Musatov A, Tomášková N. Anion-Specific Effects on the Alkaline State of Cytochrome c. BIOCHEMISTRY (MOSCOW) 2021; 86:59-73. [PMID: 33705282 DOI: 10.1134/s0006297921010065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Specific effects of anions on the structure, thermal stability, and peroxidase activity of native (state III) and alkaline (state IV) cytochrome c (cyt c) have been studied by the UV-VIS absorbance spectroscopy, intrinsic tryptophan fluorescence, and circular dichroism. Thermal and isothermal denaturation monitored by the tryptophan fluorescence and circular dichroism, respectively, implied lower stability of cyt c state IV in comparison with the state III. The pKa value of alkaline isomerization of cyt c depended on the present salts, i.e., kosmotropic anions increased and chaotropic anions decreased pKa (Hofmeister effect on protein stability). The peroxidase activity of cyt c in the state III, measured by oxidation of guaiacol, showed clear dependence on the salt position in the Hofmeister series, while cyt c in the alkaline state lacked the peroxidase activity regardless of the type of anions present in the solution. The alkaline isomerization of cyt c in the presence of 8 M urea, measured by Trp59 fluorescence, implied an existence of a high-affinity non-native ligand for the heme iron even in a partially denatured protein conformation. The conformation of the cyt c alkaline state in 8 M urea was considerably modulated by the specific effect of anions. Based on the Trp59 fluorescence quenching upon titration to alkaline pH in 8 M urea and molecular dynamics simulation, we hypothesize that the Lys79 conformer is most likely the predominant alkaline conformer of cyt c. The high affinity of the sixth ligand for the heme iron is likely a reason of the lack of peroxidase activity of cyt c in the alkaline state.
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Affiliation(s)
- Erik Sedlák
- Department of Biochemistry, Faculty of Science, P. J. Šafárik University in Košice, Košice, 04154, Slovakia. .,Centre for Interdisciplinary Biosciences, P. J. Šafárik University in Košice, Košice, 04154, Slovakia
| | - Tibor Žár
- Centre for Interdisciplinary Biosciences, P. J. Šafárik University in Košice, Košice, 04154, Slovakia.
| | - Rastislav Varhač
- Department of Biochemistry, Faculty of Science, P. J. Šafárik University in Košice, Košice, 04154, Slovakia.
| | - Andrej Musatov
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Košice, 040 01, Slovakia.
| | - Nataša Tomášková
- Department of Biochemistry, Faculty of Science, P. J. Šafárik University in Košice, Košice, 04154, Slovakia.
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2
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Sun SC, Huang HW, Lo YT, Chuang MC, Hsu YHH. Unraveling cardiolipin-induced conformational change of cytochrome c through H/D exchange mass spectrometry and quartz crystal microbalance. Sci Rep 2021; 11:1090. [PMID: 33441668 PMCID: PMC7806790 DOI: 10.1038/s41598-020-79905-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/04/2020] [Indexed: 11/21/2022] Open
Abstract
Cardiolipin (CL), a crucial component in inner mitochondrial membranes, interacts with cytochrome c (cyt c) to form a peroxidase complex for the catalysis of CL oxidation. Such interaction is pivotal to the mitochondrial regulation of apoptosis and is affected by the redox state of cyt c. In the present study, the redox-dependent interaction of cyt c with CL was investigated through amide hydrogen/deuterium exchange coupled with mass spectrometry (HDXMS) and quartz crystal microbalance with dissipation monitoring (QCM-D). Ferrous cyt c exhibited a more compact conformation compared with its ferric form, which was supported by the lower number of deuterons accumulated and the greater amplitude reduction on dissipation. Upon association with CL, ferrous cyt c resulted in a moderate increase in deuteration, whereas the ferric form caused a drastic increase of deuteration, which indicated that CL-bound ferric cyt c formed an extended conformation. These results were consistent with those of the frequency (f) − dissipation (D) experiments, which revealed that ferric cyt c yielded greater values of |ΔD/Δf| within the first minute. Further fragmentation analysis based on HDXMS indicated that the effect of CL binding was considerably different on ferric and ferrous cyt c in the C-helix and the Loop 9–24. In ferric cyt c, CL binding affected Met80 and destabilized His18 interaction with heme, which was not observed with ferrous cyt c. An interaction model was proposed to explain the aforementioned results.
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Affiliation(s)
- Sin-Cih Sun
- Department of Chemistry, Tunghai University, Taichung, Taiwan
| | - Hung-Wei Huang
- Department of Chemistry, Tunghai University, Taichung, Taiwan
| | - Yi-Ting Lo
- Department of Chemistry, Tunghai University, Taichung, Taiwan
| | - Min-Chieh Chuang
- Department of Chemistry, Tunghai University, Taichung, Taiwan. .,Department of Environmental Science and Engineering, Taichung, Taiwan.
| | - Yuan-Hao Howard Hsu
- Department of Chemistry, Tunghai University, Taichung, Taiwan. .,Biological Science Center, Tunghai University, Taichung, Taiwan.
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3
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Garajová K, Sedláková D, Berta M, Gazova Z, Sedlák E. Destabilization effect of imidazolium cation-Hofmeister anion salts on cytochrome c. Int J Biol Macromol 2020; 164:3808-3813. [DOI: 10.1016/j.ijbiomac.2020.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/24/2020] [Accepted: 09/02/2020] [Indexed: 01/15/2023]
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4
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Chea EE, Deredge DJ, Jones LM. Insights on the Conformational Ensemble of Cyt C Reveal a Compact State during Peroxidase Activity. Biophys J 2019; 118:128-137. [PMID: 31810655 DOI: 10.1016/j.bpj.2019.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/29/2019] [Accepted: 11/11/2019] [Indexed: 12/19/2022] Open
Abstract
Cytochrome c (cyt c) is known for its role in the electron transport chain but transitions to a peroxidase-active state upon exposure to oxidative species. The peroxidase activity ultimately results in the release of cyt c into the cytosol for the engagement of apoptosis. The accumulation of oxidative modifications that accompany the onset of the peroxidase function are well-characterized. However, the concurrent structural and conformational transitions of cyt c remain undercharacterized. Fast photochemical oxidation of proteins (FPOP) coupled with mass spectrometry is a protein footprinting technique used to structurally characterize proteins. FPOP coupled with native ion mobility separation shows that exposure to H2O2 results in the accumulation of a compact state of cyt c. Subsequent top-down fragmentation to localize FPOP modifications reveals changes in heme coordination between conformers. A time-resolved functional assay suggests that this compact conformer is peroxidase active. Altogether, combining FPOP, ion mobility separation, and top-down and bottom-up mass spectrometry allows us to discern individual conformations in solution and obtain a better understanding of the conformational ensemble and structural transitions of cyt c as it transitions from a respiratory role to a proapoptotic role.
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Affiliation(s)
- Emily E Chea
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland
| | - Daniel J Deredge
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland
| | - Lisa M Jones
- Department of Pharmaceutical Sciences, University of Maryland Baltimore, Baltimore, Maryland.
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5
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Lei H, Nold SM, Motta LJ, Bowler BE. Effect of V83G and I81A Substitutions to Human Cytochrome c on Acid Unfolding and Peroxidase Activity below a Neutral pH. Biochemistry 2019; 58:2921-2933. [DOI: 10.1021/acs.biochem.9b00295] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Haotian Lei
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812, United States
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812, United States
| | - Shiloh M. Nold
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812, United States
| | - Luis Jung Motta
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812, United States
| | - Bruce E. Bowler
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812, United States
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812, United States
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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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Tomášková N, Varhač R, Lysáková V, Musatov A, Sedlák E. Peroxidase activity of cytochrome c in its compact state depends on dynamics of the heme region. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:1073-1083. [DOI: 10.1016/j.bbapap.2018.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/06/2018] [Accepted: 09/10/2018] [Indexed: 10/28/2022]
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8
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Elmer-Dixon MM, Bowler BE. Electrostatic Constituents of the Interaction of Cardiolipin with Site A of Cytochrome c. Biochemistry 2018; 57:5683-5695. [DOI: 10.1021/acs.biochem.8b00704] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Margaret M. Elmer-Dixon
- Department of Chemistry and Biochemistry, Center for Bimolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812, United States
| | - Bruce E. Bowler
- Department of Chemistry and Biochemistry, Center for Bimolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812, United States
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Nold SM, Lei H, Mou TC, Bowler BE. Effect of a K72A Mutation on the Structure, Stability, Dynamics, and Peroxidase Activity of Human Cytochrome c. Biochemistry 2017; 56:3358-3368. [PMID: 28598148 PMCID: PMC5564420 DOI: 10.1021/acs.biochem.7b00342] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We test the hypothesis that Lys72 suppresses the intrinsic peroxidase activity of human cytochrome c, as observed previously for yeast iso-1-cytochrome c [McClelland, L. J., et al. (2014) Proc. Natl. Acad. Sci. U. S. A. 111, 6648-6653]. A 1.25 Å X-ray structure of K72A human cytochrome c shows that the mutation minimally affects structure. Guanidine hydrochloride denaturation demonstrates that the K72A mutation increases global stability by 0.5 kcal/mol. The K72A mutation also increases the apparent pKa of the alkaline transition, a measure of the stability of the heme crevice, by 0.5 unit. Consistent with the increase in the apparent pKa, the rate of formation of the dominant alkaline conformer decreases, and this conformer is no longer stabilized by proline isomerization. Peroxidase activity measurements show that the K72A mutation increases kcat by 1.6-4-fold at pH 7-10, an effect larger than that seen for the yeast protein. X-ray structures of wild type and K72A human cytochrome c indicate that direct interactions of Lys72 with the far side of Ω-loop D, which are seen in X-ray structures of horse and yeast cytochrome c and could suppress peroxidase activity, are lacking. Instead, we propose that the stronger effect of the K72A mutation on the peroxidase activity of human versus yeast cytochrome c results from relief of steric interactions between the side chains at positions 72 and 81 (Ile in human vs Ala in yeast), which suppress the dynamics of Ω-loop D necessary for the intrinsic peroxidase activity of cytochrome c.
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Affiliation(s)
- Shiloh M. Nold
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812
- Center for Bimolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812
| | - Haotian Lei
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812
- Center for Bimolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812
| | - Tung-Chung Mou
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812
- Center for Bimolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812
| | - Bruce E. Bowler
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812
- Center for Bimolecular Structure and Dynamics, University of Montana, Missoula, Montana 59812
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Malyshka D, Schweitzer-Stenner R. Ferrocyanide-Mediated Photoreduction of Ferricytochrome C Utilized to Selectively Probe Non-native Conformations Induced by Binding to Cardiolipin-Containing Liposomes. Chemistry 2016; 23:1151-1156. [PMID: 27859757 DOI: 10.1002/chem.201604992] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Indexed: 01/29/2023]
Abstract
Ferricytochrome c binding to cardiolipin-containing liposomes produces a heterogeneous distribution of conformations comprising native-like and non-native misfolded proteins. We utilized the photoreduction of native ferricytochrome c in the presence of potassium ferrocyanide and resonance Raman spectroscopy to probe the population of native and misfolded cytochrome c on liposomes with 20 % tetraoleylcardiolipin (TOCL)/80 % dioleylphosphocholine (DOPC) and with 100 % TOCL as a function of TOCL concentration. Our data provided strong support for an earlier model, which predicts that the equilibrium between native and non-native conformations is shifted to the latter with decreasing protein occupation of liposomes.
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Affiliation(s)
- Dmitry Malyshka
- Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104, USA
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11
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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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12
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Goldes ME, Jeakins-Cooley ME, McClelland LJ, Mou TC, Bowler BE. Disruption of a hydrogen bond network in human versus spider monkey cytochrome c affects heme crevice stability. J Inorg Biochem 2015; 158:62-69. [PMID: 26775610 DOI: 10.1016/j.jinorgbio.2015.12.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 12/03/2015] [Accepted: 12/28/2015] [Indexed: 11/30/2022]
Abstract
The hypothesis that the recent rapid evolution of primate cytochromes c, which primarily involves residues in the least stable Ω-loop (Ω-loop C, residues 40-57), stabilizes the heme crevice of cytochrome c relative to other mammals, is tested. To accomplish this goal, we have compared the properties of human and spider monkey cytochrome c and a set of four variants produced in the process of converting human cytochrome c into spider monkey cytochrome c. The global stability of all variants has been measured by guanidine hydrochloride denaturation. The stability of the heme crevice has been assessed with the alkaline conformational transition. Structural insight into the effects of the five amino acid substitutions needed to convert human cytochrome c into spider monkey cytochrome c is provided by a 1.15Å resolution structure of spider monkey cytochrome c. The global stability for all variants is near 9.0kcal/mol at 25°C and pH7, which is higher than that observed for other mammalian cytochromes c. The heme crevice stability is more sensitive to the substitutions required to produce spider monkey cytochrome c with decreases of up to 0.5 units in the apparent pKa of the alkaline conformational transition relative to human cytochrome c. The structure of spider monkey cytochrome c indicates that the Y46F substitution destabilizes the heme crevice by disrupting an extensive hydrogen bond network that connects three surface loops including Ω-loop D (residues 70-85), which contains the Met80 heme ligand.
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Affiliation(s)
- Matthew E Goldes
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT 59812, United States
| | | | - Levi J McClelland
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT 59812, United States; Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, United States
| | - Tung-Chung Mou
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, United States; Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, United States
| | - Bruce E Bowler
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT 59812, United States; Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, United States.
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Pandiscia LA, Schweitzer-Stenner R. Coexistence of Native-Like and Non-Native Cytochrome c on Anionic Liposomes with Different Cardiolipin Content. J Phys Chem B 2015; 119:12846-59. [PMID: 26369421 DOI: 10.1021/acs.jpcb.5b07328] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We employed a combination of fluorescence, visible circular dichroism, and absorption spectroscopy to study the conformational changes of ferricytochrome c upon its binding to cardiolipin-containing small unilamellar vesicles. The measurements were performed as a function of the cardiolipin concentration, the cardiolipin content of the liposomes, and the NaCl concentration of the solvent. The data were analyzed with a novel model that combines a single binding step with a conformational equilibrium between native-like and non-native-like proteins bound to the membrane surface. The equilibrium between the two conformations, which themselves are comprised of structurally slightly different subconformations, shifts to the more non-native-like conformation with increasing cardiolipin concentration. For the binding isotherms described in this paper, we explicitly considered the enthalpic and entropic contributions of molecular crowding to protein binding at low lipid concentrations and high occupancy of the liposome surface. Increasing the CL content of liposomes increases the overall binding affinity but makes the conformational distribution much more susceptible to the influence of sodium and chloride ions, which shifts the equilibrium toward the more native-like state and directly inhibits binding, particularly to liposomes with 100% cardiolipin content. Spectroscopic evidence further suggests that a fraction of the non-native conformers adopts a pentacoordinated state similar to those obtained in class C peroxidases. On the basis of our results, we propose a hypothesis that describes the balance between facilitating and impeding forces controlling the peroxidase activity of cytochrome c in the inner membrane space of mitochondria.
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Affiliation(s)
- Leah A Pandiscia
- 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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14
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Soffer JB, Schweitzer-Stenner R. Near-exact enthalpy–entropy compensation governs the thermal unfolding of protonation states of oxidized cytochrome c. J Biol Inorg Chem 2014; 19:1181-94. [DOI: 10.1007/s00775-014-1174-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 06/16/2014] [Indexed: 11/24/2022]
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15
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De March M, Demitri N, De Zorzi R, Casini A, Gabbiani C, Guerri A, Messori L, Geremia S. Nitrate as a probe of cytochrome c surface: Crystallographic identification of crucial “hot spots” for protein–protein recognition. J Inorg Biochem 2014; 135:58-67. [DOI: 10.1016/j.jinorgbio.2014.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 02/23/2014] [Accepted: 02/27/2014] [Indexed: 11/30/2022]
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16
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Soffer JB, Fradkin E, Pandiscia LA, Schweitzer-Stenner R. The (Not Completely Irreversible) Population of a Misfolded State of Cytochrome c under Folding Conditions. Biochemistry 2013; 52:1397-408. [DOI: 10.1021/bi301586e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jonathan B. Soffer
- Departments of Chemistry and
Biology, Drexel University, 3141 Chestnut
Street, Philadelphia, Pennsylvania 19104, United
States
| | - Emma Fradkin
- Departments of Chemistry and
Biology, Drexel University, 3141 Chestnut
Street, Philadelphia, Pennsylvania 19104, United
States
| | - Leah A. Pandiscia
- Departments of Chemistry and
Biology, Drexel University, 3141 Chestnut
Street, Philadelphia, Pennsylvania 19104, United
States
| | - Reinhard Schweitzer-Stenner
- Departments of Chemistry and
Biology, Drexel University, 3141 Chestnut
Street, Philadelphia, Pennsylvania 19104, United
States
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17
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Cherney MM, Junior CC, Bowler BE. Mutation of trimethyllysine 72 to alanine enhances His79-heme-mediated dynamics of iso-1-cytochrome c. Biochemistry 2013; 52:837-46. [PMID: 23311346 DOI: 10.1021/bi301599g] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Trimethyllysine 72 (Tml72) of yeast iso-1-cytochrome c lies across the surface of the heme crevice loop (Ω-loop D, residues 70-85) like a brace. Lys72 is oriented similarly in horse cytochrome c (Cytc). To determine whether this residue affects the dynamics of opening the heme crevice loop, we have studied the effect of a Tml72 to Ala substitution on the formation of the His79-heme alkaline conformer near neutral pH using a variant of iso-1-Cytc including K72A and K79H mutations. Guanidine hydrochloride denaturation shows that the Tml72 to Ala substitution within error does not affect the global stability of the protein. The effect of the Tml72 to Ala substitution on the thermodynamics of the His79-heme alkaline transition is also small. However, pH-jump kinetic studies of the His79-heme alkaline transition show that both the forward and backward rates of conformational change are increased by the Tml72 to Ala substitution. The barrier for opening the heme crevice is reduced by 0.5 kcal/mol and for closing the heme crevice by 0.3 kcal/mol. The ability of Tml72 to modulate the heme crevice dynamics may indicate a crucial role in regulating function, such as in the peroxidase activity seen in the early stages of apoptosis.
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Affiliation(s)
- Melisa M Cherney
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, United States
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Conformational substates of ferricytochrome c revealed by combined optical absorption and electronic circular dichroism spectroscopy at cryogenic temperature. Biophys Chem 2009; 147:8-12. [PMID: 20022687 DOI: 10.1016/j.bpc.2009.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 12/02/2009] [Indexed: 11/22/2022]
Abstract
We have investigated the heterogeneity of the Fe(III)-Met80 linkage of horse heart ferricytochrome c by probing the 695nm charge transfer band with absorption and electronic circular dichroism (ECD) spectroscopy. In order to verify the connection between conformational substates of the Fe(III)-Met80 linkage and the 695nm band spectral heterogeneity, we have performed experiments as a function of pH (neutral and acidic) and temperature (room and 20K). At room temperature, the ECD spectrum is blue shifted with respect to the absorption one; the shift is more pronounced at acidic pH and is compatible with the presence of sub-bands. ECD measurements at 20K highlighted the heterogeneous nature of the 695nm band and provided direct experimental evidence for the presence of sub-bands. Indeed, while the absorption spectra remained deceivingly unstructured, the ECD spectra showed well resolved peaks and shoulders. A consistent fit of the 20K absorption and ECD spectra showed that five Gaussians (each centered at the same frequency in the absorption and ECD spectrum) are able to reproduce the observed lineshapes. A careful analysis of frequency shifts and intensity ratios of these sub-bands enabled us to identify at least three distinct sub-bands arising from taxonomic conformational substates of the Fe(III)-Met80 linkage. In view of the major influence of the Fe(III)-Met80 linkage on the redox potential of ferricytochrome c, we speculate that these spectrally distinguishable substates may have different functional roles.
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Varhač R, Tomášková N, Fabián M, Sedlák E. Kinetics of cyanide binding as a probe of local stability/flexibility of cytochrome c. Biophys Chem 2009; 144:21-6. [DOI: 10.1016/j.bpc.2009.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Revised: 05/30/2009] [Accepted: 06/01/2009] [Indexed: 10/20/2022]
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Ying T, Zhong F, Xie J, Feng Y, Wang ZH, Huang ZX, Tan X. Evolutionary alkaline transition in human cytochrome c. J Bioenerg Biomembr 2009; 41:251-7. [PMID: 19593652 DOI: 10.1007/s10863-009-9223-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 06/07/2009] [Indexed: 12/01/2022]
Abstract
Conformational transitions in cytochrome c (cyt c) are being realized to be responsible for its multi-functions. Among a number of conformational transitions in cyt c, the alkaline transition has attracted much attention. The cDNA of human cyt c is cloned by RT-PCR and a high-effective expression system for human cyt c has been developed in this study. The equilibrium and kinetics of the alkaline transition of human cyt c have been systematically investigated for the first time, and compared with those of yeast and horse cyt c from an evolutionary perspective. The pK(a) value for the alkaline transition of human cyt c is apparently higher than that of yeast and horse. Kinetic studies suggest that it is increasingly difficult for the alkaline transition of cyt c from yeast, horse and human. Molecular modeling of human cyt c shows that the omega loop where the lysine residue is located apparently further away from heme in human cyt c than in yeast iso-1 and horse heart cyt c. These results regarding alkaline conformational transition provide valuable information for understanding the molecular basis for the biological multi-functions of cyt c.
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Affiliation(s)
- Tianlei Ying
- Department of Chemistry & Institutes of Biomedical Sciences, Fudan University, Shanghai, China
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Wiederkehr RS, Hoops GC, Aslan MM, Byard CL, Mendes SB. Investigations on the Q and CT Bands of Cytochrome c Submonolayer Adsorbed on an Alumina Surface Using Broadband Spectroscopy with Single-Mode Integrated Optical Waveguides. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2009; 113:8306-8312. [PMID: 21289870 PMCID: PMC3031143 DOI: 10.1021/jp810845e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this work, we report experimental results on the molar absorptivity of cytochrome c adsorbed at different submonolayer levels onto an aluminum oxide waveguide surface; our data show a clear dependence of the protein optical properties on its surface density. The measurements were performed using the broadband, single-mode, integrated optical waveguide spectroscopic technique, which is an extremely sensitive tool able to reach submonolayer levels of detection required for this type of studies. This investigation focuses on the molar absorptivity at the Q-band (centered at 525 nm) and, for the first time to our knowledge, the weak charge transfer (CT) band (centered at 695 nm) of surface-adsorbed cyt c. Polarized light in the spectral region from 450 to 775 nm was all-coupled into an alumina thin film, which functioned as a single-mode planar optical waveguide. The alumina thin-film waveguide used for this work had a thickness of 180 nm and was deposited on a glass substrate by the atomic layer deposition process. The protein submonolayer was formed on the alumina waveguide surface through electrostatic adsorption from an aqueous buffer solution at neutral pH. The optical properties of the surface-adsorbed cyt c were investigated for bulk protein concentrations ranging from 5 nM to 8200 nM in the aqueous buffer solution. For a protein surface density of 2.3 pmol/cm(2), the molar absorptivity measured at the charge transfer band was 335 M(-1) cm(-1), and for a surface density of 15 pmol/cm(2) was 720 M(-1) cm(-1), which is much closer to the value of cyt c dissolved in an aqueous neutral buffer (830 M(-1) cm(-1)). The modification of the protein molar absorptivity and its dependence on the surface density can most likely be attributed to conformational changes of the surface-adsorbed species.
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Affiliation(s)
| | | | | | | | - Sergio B. Mendes
- Corresponding author. Phone: +1 502 852-0908. Fax: +1 502 852-8128.
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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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Schweitzer-Stenner R, Hagarman A, Verbaro D, Soffer JB. Conformational Stability of Cytochrome c Probed by Optical Spectroscopy. Methods Enzymol 2009; 466:109-53. [DOI: 10.1016/s0076-6879(09)66006-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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