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Cytochrome c: An extreme multifunctional protein with a key role in cell fate. Int J Biol Macromol 2019; 136:1237-1246. [DOI: 10.1016/j.ijbiomac.2019.06.180] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/24/2019] [Accepted: 06/24/2019] [Indexed: 01/25/2023]
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2
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Placido T, Tognaccini L, Howes BD, Montrone A, Laquintana V, Comparelli R, Curri ML, Smulevich G, Agostiano A. Surface Engineering of Gold Nanorods for Cytochrome c Bioconjugation: An Effective Strategy To Preserve the Protein Structure. ACS OMEGA 2018; 3:4959-4967. [PMID: 30221229 PMCID: PMC6130780 DOI: 10.1021/acsomega.8b00719] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 04/26/2018] [Indexed: 06/08/2023]
Abstract
The surface of gold nanorods (Au NRs) has been appropriately engineered to achieve a suitable interface for bioconjugation with horse heart cytochrome c (HCc). HCc, an extensively studied and well-characterized protein, represents an ideal model for nanoparticle (NP)-protein conjugation studies because of its small size, high stability, and commercial availability. Here, the native state of the protein has been demonstrated for the first time, by means of Raman spectroscopy, to be retained upon conjugation with the anisotropic Au nanostructures, thus validating the proposed protocol as specifically suited to mostly preserve the plasmonic properties of the NRs and to retain the structure of the protein. The successful creation of such bioconjugates with the retention of the protein structure and function along with the preservation of the NP properties represents a challenging but essential task, as it provides the only way to access functional hybrid systems with potential applications in biotechnology, medicine, and catalysis. In this perspective, the organic capping surrounding the Au NRs plays a key role, as it represents the functional interface for the conjugation step. Cetyltrimethylammonium bromide-coated Au NRs, prepared by using a seed-mediated synthetic route, have been wrapped with polyacrylic acid (PAA) by means of electrostatic interactions following a layer-by-layer approach. The resulting water-dispersible negatively charged AuNRs@PAA NPs have then been electrostatically bound to the positively charged HCc. The bioconjugation procedure has been thoroughly monitored by the combined analysis of UV-vis absorption, resonance Raman and Fourier transform infrared spectroscopies, transmission electron microscopy microscopy, and ζ-potential, which verified the successful conjugation of the protein to the nanorods.
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Affiliation(s)
- Tiziana Placido
- CNR-IPCF
Istituto per I Processi Chimico-Fisici, S.S. Bari, c/o Dip. Chimica, Via Orabona 4, 70126 Bari, Italy
| | - Lorenzo Tognaccini
- Dipartimento
di Chimica “Ugo Schiff”, Università
di Firenze, Via della
Lastruccia 3-13, Sesto Fiorentino, 50019 Florence, Italy
| | - Barry D. Howes
- Dipartimento
di Chimica “Ugo Schiff”, Università
di Firenze, Via della
Lastruccia 3-13, Sesto Fiorentino, 50019 Florence, Italy
| | - Alessandro Montrone
- Università
degli Studi di Bari—Dip. di Chimica, Via Orabona 4, 70126 Bari, Italy
| | - Valentino Laquintana
- Dipartimento
di Farmacia—Scienze del Farmaco, Università degli Studi di Bari, Via Orabona 4, 70126 Bari, Italy
| | - Roberto Comparelli
- CNR-IPCF
Istituto per I Processi Chimico-Fisici, S.S. Bari, c/o Dip. Chimica, Via Orabona 4, 70126 Bari, Italy
| | - M. Lucia Curri
- CNR-IPCF
Istituto per I Processi Chimico-Fisici, S.S. Bari, c/o Dip. Chimica, Via Orabona 4, 70126 Bari, Italy
| | - Giulietta Smulevich
- Dipartimento
di Chimica “Ugo Schiff”, Università
di Firenze, Via della
Lastruccia 3-13, Sesto Fiorentino, 50019 Florence, Italy
| | - Angela Agostiano
- CNR-IPCF
Istituto per I Processi Chimico-Fisici, S.S. Bari, c/o Dip. Chimica, Via Orabona 4, 70126 Bari, Italy
- Università
degli Studi di Bari—Dip. di Chimica, Via Orabona 4, 70126 Bari, Italy
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3
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Singh UK, Patel R. Dynamics of Ionic Liquid-Assisted Refolding of Denatured Cytochrome c: A Study of Preferential Interactions toward Renaturation. Mol Pharm 2018; 15:2684-2697. [PMID: 29767978 DOI: 10.1021/acs.molpharmaceut.8b00212] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In vitro refolding of denatured protein and the influence of the alkyl chain on the refolding of a protein were tested using long chain imidazolium chloride salts, 1-methyl-3-octylimidazolium chloride [C8mim][Cl], and 1-decyl-3-methylimidazolium chloride [C10mim][Cl]. The horse heart cytochrome c (h-cyt c) was denatured by urea and guanidinium hydrochloride (GdnHCl), as well as by base-induced denaturation at pH 13, to provide a broad overview of the overall refolding behavior. The variation in the alkyl chain of the ionic liquids (ILs) showed a profound effect on the refolding of denatured h-cyt c. The ligand-induced refolding was correlated to understand the mechanism of the conformational stability of proteins in aqueous solutions of ILs. The results showed that the long chain ILs having the [C8mim]+ and [C10mim]+ cations promote the refolding of alkali-denatured h-cyt c. The IL having the [C10mim]+ cation efficiently refolded the alkali-denatured h-cyt c with the formation of the MG state, whereas the IL having the [C8mim]+ cation, which is known to be compatible for protein stability, shows slight refolding and forms a different transition state. The lifetime results show successful refolding of alkaline-denatured h-cyt c by both of the ILs, however, more refolding was observed in the case of [C10mim][Cl], and this was correlated with the fast and medium lifetimes (τ1 and τ2) obtained, which show an increase accompanied by an increase in secondary structure. The hydrophobic interactions plays an important role in the refolding of chemically and alkali-denatured h-cyt c by long chain imidazolium ILs. The formation of the MG state by [C10mim][Cl] was also confirmed, as some regular structure exists far below the CMC of IL. The overall results suggested that the [C10mim]+ cation bound to the unfolded h-cyt c triggers its refolding by electrostatic and hydrophobic interactions that stabilize the MG state.
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Affiliation(s)
- Upendra Kumar Singh
- Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia (A Central University) , New Delhi 110025 , India
| | - Rajan Patel
- Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia (A Central University) , New Delhi 110025 , India
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Alvarez-Paggi D, Hannibal L, Castro MA, Oviedo-Rouco S, Demicheli V, Tórtora V, Tomasina F, Radi R, Murgida DH. Multifunctional Cytochrome c: Learning New Tricks from an Old Dog. Chem Rev 2017; 117:13382-13460. [DOI: 10.1021/acs.chemrev.7b00257] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Damián Alvarez-Paggi
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Luciana Hannibal
- Department
of Pediatrics, Universitätsklinikum Freiburg, Mathildenstrasse 1, Freiburg 79106, Germany
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - María A. Castro
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Santiago Oviedo-Rouco
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Veronica Demicheli
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Veronica Tórtora
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Florencia Tomasina
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Rafael Radi
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Daniel H. Murgida
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
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Arianna C, Eliana C, Flavio A, Marco R, Giacomo D, Manuel S, Elena B, Alessandra G. Rapid Rapamycin-Only Induced Osteogenic Differentiation of Blood-Derived Stem Cells and Their Adhesion to Natural and Artificial Scaffolds. Stem Cells Int 2017; 2017:2976541. [PMID: 28814956 PMCID: PMC5549509 DOI: 10.1155/2017/2976541] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 06/11/2017] [Indexed: 02/08/2023] Open
Abstract
Stem cells are a centerpiece of regenerative medicine research, and the recent development of adult stem cell-based therapy systems has vigorously expanded the scope and depth of this scientific field. The regeneration of damaged and/or degraded bone tissue in orthopedic, dental, or maxillofacial surgery is one of the main areas where stem cells and their regenerative potential could be used successfully, requiring tissue engineering solutions incorporating an ideal stem cell type paired with the correct mechanical support. Our contribution to this ongoing research provides a new model of in vitro osteogenic differentiation using blood-derived stem cells (BDSCs) and rapamycin, visibly expressing typical osteogenic markers within ten days of treatment. In depth imaging studies allowed us to observe the adhesion, proliferation, and differentiation of BDSCs to both titanium and bone scaffolds. We demonstrate that BDSCs can differentiate towards the osteogenic lineage rapidly, while readily adhering to the scaffolds we exposed them to. Our results show that our model can be a valid tool to study the molecular mechanisms of osteogenesis while tailoring tissue engineering solutions to these new insights.
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Affiliation(s)
- Carpentieri Arianna
- Biochemistry Laboratory, Department of Experimental Medicine and Surgery, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Cozzoli Eliana
- Biochemistry Laboratory, Department of Experimental Medicine and Surgery, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Acri Flavio
- Baxter Healthcare Ltd, Caxton Way, Thetford, UK
| | - Ranalli Marco
- Biochemistry Laboratory, Department of Experimental Medicine and Surgery, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Diedenhofen Giacomo
- Biochemistry Laboratory, Department of Experimental Medicine and Surgery, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Scimeca Manuel
- Biochemistry Laboratory, Department of Experimental Medicine and Surgery, University of Rome “Tor Vergata”, 00133 Rome, Italy
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy
- OrchideaLab S.r.l., Via del Grecale 6, Morlupo, Rome, Italy
| | - Bonanno Elena
- Biochemistry Laboratory, Department of Experimental Medicine and Surgery, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Gambacurta Alessandra
- Biochemistry Laboratory, Department of Experimental Medicine and Surgery, University of Rome “Tor Vergata”, 00133 Rome, Italy
- NAST Centre for Nanoscience, University of Rome “Tor Vergata”, 00133 Rome, Italy
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6
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Ciaccio C, Tognaccini L, Battista T, Cervelli M, Howes BD, Santucci R, Coletta M, Mariottini P, Smulevich G, Fiorucci L. The Met80Ala and Tyr67His/Met80Ala mutants of human cytochrome c shed light on the reciprocal role of Met80 and Tyr67 in regulating ligand access into the heme pocket. J Inorg Biochem 2017; 169:86-96. [DOI: 10.1016/j.jinorgbio.2017.01.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 01/13/2017] [Accepted: 01/20/2017] [Indexed: 10/20/2022]
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7
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Milazzo L, Tognaccini L, Howes BD, Sinibaldi F, Piro MC, Fittipaldi M, Baratto MC, Pogni R, Santucci R, Smulevich G. Unravelling the Non-Native Low-Spin State of the Cytochrome c–Cardiolipin Complex: Evidence of the Formation of a His-Ligated Species Only. Biochemistry 2017; 56:1887-1898. [DOI: 10.1021/acs.biochem.6b01281] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lisa Milazzo
- Dipartimento
di Chimica “Ugo Schiff”, Università di Firenze, Via della
Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Lorenzo Tognaccini
- Dipartimento
di Chimica “Ugo Schiff”, Università di Firenze, Via della
Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Barry D. Howes
- Dipartimento
di Chimica “Ugo Schiff”, Università di Firenze, Via della
Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Federica Sinibaldi
- Dipartimento
di Medicina Sperimentale e Chirurgia, Università di Roma “Tor Vergata”, Via
Montpellier 1, 00133 Rome, Italy
| | - Maria C. Piro
- Dipartimento
di Medicina Sperimentale e Chirurgia, Università di Roma “Tor Vergata”, Via
Montpellier 1, 00133 Rome, Italy
| | - Maria Fittipaldi
- Dipartimento
di Fisica ed Astronomia, Università di Firenze, Via Sansone
1, 50019 Sesto Fiorentino
(FI), Italy
| | - Maria C. Baratto
- Dipartimento
di Biotecnologie, Chimica e Farmacia, Università di Siena, Via Aldo Moro
2, 53100 Siena, Italy
| | - Rebecca Pogni
- Dipartimento
di Biotecnologie, Chimica e Farmacia, Università di Siena, Via Aldo Moro
2, 53100 Siena, Italy
| | - Roberto Santucci
- Dipartimento
di Scienze Cliniche e Medicina Traslazionale, Università di Roma “Tor Vergata”, Via
Montpellier 1, 00133 Rome, Italy
| | - Giulietta Smulevich
- Dipartimento
di Chimica “Ugo Schiff”, Università di Firenze, Via della
Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
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8
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Tognaccini L, Ciaccio C, D'Oria V, Cervelli M, Howes BD, Coletta M, Mariottini P, Smulevich G, Fiorucci L. Structure-function relationships in human cytochrome c: The role of tyrosine 67. J Inorg Biochem 2015; 155:56-66. [PMID: 26610191 DOI: 10.1016/j.jinorgbio.2015.11.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 11/03/2015] [Accepted: 11/10/2015] [Indexed: 11/20/2022]
Abstract
Spectroscopic and functional properties of human cytochrome c and its Tyr67 residue mutants (i.e., Tyr67His and Tyr67Arg) have been investigated. In the case of the Tyr67His mutant, we have observed only a very limited structural alteration of the heme pocket and of the Ω-loop involving, among others, the residue Met80 and its bond with the heme iron. Conversely, in the Tyr67Arg mutant the Fe-Met80 bond is cleaved; consequently, a much more extensive structural alteration of the Ω-loop can be envisaged. The structural, and thus the functional modifications, of the Tyr67Arg mutant are present in both the ferric [Fe(III)] and the ferrous [Fe(II)] forms, indicating that the structural changes are independent of the heme iron oxidation state, depending instead on the type of substituting residue. Furthermore, a significant peroxidase activity is evident for the Tyr67Arg mutant, highlighting the role of Arg as a basic, positively charged residue at pH7.0, located in the heme distal pocket, which may act as an acid to cleave the O-O bond in H2O2. As a whole, our results indicate that a delicate equilibrium is associated with the spatial arrangement of the Ω-loop. Clearly, Arg, but not His, is able to stabilize and polarize the negative charge on the Fe(III)-OOH complex during the formation of Compound I, with important consequences on cytochrome peroxidation activity and its role in the apoptotic process, which is somewhat different in yeast and mammals.
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Affiliation(s)
- Lorenzo Tognaccini
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, FI, Italy
| | - Chiara Ciaccio
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy; Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems (CIRCMSB), Bari, Italy
| | - Valentina D'Oria
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy
| | | | - Barry D Howes
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, FI, Italy
| | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy; Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems (CIRCMSB), Bari, Italy
| | | | - Giulietta Smulevich
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino, FI, Italy; Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems (CIRCMSB), Bari, Italy.
| | - Laura Fiorucci
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, Rome, Italy.
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9
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Sinibaldi F, Howes BD, Droghetti E, Polticelli F, Piro MC, Di Pierro D, Fiorucci L, Coletta M, Smulevich G, Santucci R. Role of lysines in cytochrome c-cardiolipin interaction. Biochemistry 2013; 52:4578-88. [PMID: 23738909 DOI: 10.1021/bi400324c] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cytochrome c undergoes structural variations during the apoptotic process; such changes have been related to modifications occurring in the protein when it forms a complex with cardiolipin, one of the phospholipids constituting the mitochondrial membrane. Although several studies have been performed to identify the site(s) of the protein involved in the cytochrome c-cardiolipin interaction, to date the location of this hosting region(s) remains unidentified and is a matter of debate. To gain deeper insight into the reaction mechanism, we investigate the role that the Lys72, Lys73, and Lys79 residues play in the cytochrome c-cardiolipin interaction, as these side chains appear to be critical for cytochrome c-cardiolipin recognition. The Lys72Asn, Lys73Asn, Lys79Asn, Lys72/73Asn, and Lys72/73/79Asn mutants of horse heart cytochrome c were produced and characterized by circular dichroism, ultraviolet-visible, and resonance Raman spectroscopies, and the effects of the mutations on the interaction of the variants with cardiolipin have been investigated. The mutants are characterized by a subpopulation with non-native axial coordination and are less stable than the wild-type protein. Furthermore, the mutants lacking Lys72 and/or Lys79 do not bind cardiolipin, and those lacking Lys73, although they form a complex with the phospholipid, do not show any peroxidase activity. These observations indicate that the Lys72, Lys73, and Lys79 residues stabilize the native axial Met80-Fe(III) coordination as well as the tertiary structure of cytochrome c. Moreover, while Lys72 and Lys79 are critical for cytochrome c-cardiolipin recognition, the simultaneous presence of Lys72, Lys73, and Lys79 is necessary for the peroxidase activity of cardiolipin-bound cytochrome c.
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Affiliation(s)
- Federica Sinibaldi
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
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10
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Sinibaldi F, Droghetti E, Polticelli F, Piro MC, Di Pierro D, Ferri T, Smulevich G, Santucci R. The effects of ATP and sodium chloride on the cytochrome c-cardiolipin interaction: the contrasting behavior of the horse heart and yeast proteins. J Inorg Biochem 2011; 105:1365-72. [PMID: 21946436 DOI: 10.1016/j.jinorgbio.2011.07.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 07/27/2011] [Accepted: 07/27/2011] [Indexed: 10/17/2022]
Abstract
In cells a portion of cytochrome c (cyt c) (15-20%) is tightly bound to cardiolipin (CL), one of the phospholipids constituting the mitochondrial membrane. The CL-bound protein, which has nonnative tertiary structure, altered heme pocket, and disrupted Fe(III)-M80 axial bond, is thought to play a role in the apoptotic process. This has attracted considerable interest in order to clarify the mechanisms governing the cyt c-CL interaction. Herein we have investigated the binding reaction of CL with the c-type cytochromes from horse heart and yeast. Although the two proteins possess a similar tertiary architecture, yeast cyt c displays lower stability and, contrary to the equine protein, it does not bind ATP and lacks pro-apoptotic activity. The study has been performed in the absence and in the presence of ATP and NaCl, two compounds that influence the (horse cyt c)-CL binding process and, thus, the pro-apoptotic activity of the protein. The two proteins behave differently: while CL interaction with horse cyt c is strongly influenced by the two effectors, no effect is observed for yeast cyt c. It is noteworthy that NaCl induces dissociation of the (horse cyt c)-CL complex but has no influence on that of yeast cyt c. The differences found for the two proteins highlight that specific structural factors, such as the different local structure conformation of the regions involved in the interactions with either CL or ATP, can significantly affect the behavior of cyt c in its reaction with liposomes and the subsequent pro-apoptotic action of the protein.
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Affiliation(s)
- Federica Sinibaldi
- Department of Experimental Medicine and Biochemical Sciences, University of Rome 'Tor Vergata', Via Montpellier 1, I-00133 Rome, Italy
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11
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Sinibaldi F, Howes BD, Piro MC, Polticelli F, Bombelli C, Ferri T, Coletta M, Smulevich G, Santucci R. Extended cardiolipin anchorage to cytochrome c: a model for protein-mitochondrial membrane binding. J Biol Inorg Chem 2010; 15:689-700. [PMID: 20238133 DOI: 10.1007/s00775-010-0636-z] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 02/14/2010] [Indexed: 11/25/2022]
Abstract
Two models have been proposed to explain the interaction of cytochrome c with cardiolipin (CL) vesicles. In one case, an acyl chain of the phospholipid accommodates into a hydrophobic channel of the protein located close the Asn52 residue, whereas the alternative model considers the insertion of the acyl chain in the region of the Met80-containing loop. In an attempt to clarify which proposal offers a more appropriate explanation of cytochrome c-CL binding, we have undertaken a spectroscopic and kinetic study of the wild type and the Asn52Ile mutant of iso-1-cytochrome c from yeast to investigate the interaction of cytochrome c with CL vesicles, considered here a model for the CL-containing mitochondrial membrane. Replacement of Asn52, an invariant residue located in a small helix segment of the protein, may provide data useful to gain novel information on which region of cytochrome c is involved in the binding reaction with CL vesicles. In agreement with our recent results revealing that two distinct transitions take place in the cytochrome c-CL binding reaction, data obtained here support a model in which two (instead of one, as considered so far) adjacent acyl chains of the liposome are inserted, one at each of the hydrophobic sites, into the same cytochrome c molecule to form the cytochrome c-CL complex.
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Affiliation(s)
- Federica Sinibaldi
- Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Università di Roma "Tor Vergata", Italy
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12
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Spectroscopic, structural, and functional characterization of the alternative low-spin state of horse heart cytochrome C. Biophys J 2008; 94:4066-77. [PMID: 18227133 DOI: 10.1529/biophysj.107.116483] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The alternative low-spin states of Fe(3+) and Fe(2+) cytochrome c induced by SDS or AOT/hexane reverse micelles exhibited the heme group in a less rhombic symmetry and were characterized by electron paramagnetic resonance, UV-visible, CD, magnetic CD, fluorescence, and Raman resonance. Consistent with the replacement of Met(80) by another strong field ligand at the sixth heme iron coordination position, Fe(3+) ALSScytc exhibited 1-nm Soret band blue shift and epsilon enhancement accompanied by disappearance of the 695-nm charge transfer band. The Raman resonance, CD, and magnetic CD spectra of Fe(3+) and Fe(2+) ALSScytc exhibited significant changes suggestive of alterations in the heme iron microenvironment and conformation and should not be assigned to unfold because the Trp(59) fluorescence remained quenched by the neighboring heme group. ALSScytc was obtained with His(33) and His(26) carboxyethoxylated horse cytochrome c and with tuna cytochrome c (His(33) replaced by Asn) pointing out Lys(79) as the probable heme iron ligand. Fe(3+) ALSScytc retained the capacity to cleave tert-butylhydroperoxide and to be reduced by dithiothreitol and diphenylacetaldehyde but not by ascorbate. Compatible with a more open heme crevice, ALSScytc exhibited a redox potential approximately 200 mV lower than the wild-type protein (+220 mV) and was more susceptible to the attack of free radicals.
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13
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Tomásková N, Varhac R, Zoldák G, Oleksáková L, Sedláková D, Sedlák E. Conformational stability and dynamics of cytochrome c affect its alkaline isomerization. J Biol Inorg Chem 2006; 12:257-66. [PMID: 17120073 DOI: 10.1007/s00775-006-0183-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2006] [Accepted: 10/06/2006] [Indexed: 11/30/2022]
Abstract
The alkaline isomerization of horse heart ferricytochrome c (cyt c) has been studied by electronic absorption spectroscopy in the presence of the Hofmeister series of anions: chloride, bromide, rhodanide and perchlorate. The anions significantly affect the apparent pK (a) value of the transition in a concentration-dependent manner according to their position in the Hofmeister series. The Soret region of the absorption spectra is not affected by the presence of the salts and shows no significant structural perturbation of the heme crevice. In the presence of perchlorate and rhodanide anions, the cyanide exchange rate between the bulk solvent and the binding site is increased. These results imply higher flexibility of the protein structure in the presence of chaotropic salts. The thermal and isothermal denaturations monitored by differential scanning calorimetry and circular dichroism, respectively, showed a decrease in the conformational stability of cyt c in the presence of the chaotropic salts. A positive correlation between the stability, DeltaG, of cyt c and the apparent pK (a) values that characterize the alkaline transition indicates the presence of a thermodynamic linkage between these conformational transitions. In addition, the rate constant of the cyanide binding and the partial molar entropies of anions negatively correlate with the pK (a) values. This indicates the important role of anion-induced solvent reorganization on the structural flexibility of cyt c in the alkaline transitions.
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Affiliation(s)
- Natasa Tomásková
- Department of Biochemistry, Faculty of Science, UPJS, Moyzesova 11, 040 01, Kosice, Slovakia
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Sinibaldi F, Howes BD, Piro MC, Caroppi P, Mei G, Ascoli F, Smulevich G, Santucci R. Insights into the role of the histidines in the structure and stability of cytochrome c. J Biol Inorg Chem 2005; 11:52-62. [PMID: 16320010 DOI: 10.1007/s00775-005-0057-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Accepted: 10/26/2005] [Indexed: 11/26/2022]
Abstract
In this paper we investigate the role played by each histidine in the amino acid sequence of yeast iso-1-cytochrome c (with the exception of H18, the residue axially coordinated to the heme iron) in determining the protein structure and stability. To this end, we have generated and characterized the double mutants H26Y/H33Y, H26Y/H39K and H33Y/H39K obtained from the C102T variant of the protein, which retain only one histidine side chain in the amino acid sequence. In particular, the H39K mutation inserts a lysine at position 39 as in the sequence of equine cytochrome c. The H26Y/H33Y/H39K triple mutant, which lacks all three histidines, was also produced and its spectroscopic properties are compared with those of the double mutants. The data highlight the critical role played by H26 in determining protein stability. Recombinant horse cytochrome c and the corresponding H26Y mutant were also generated and characterized. Since equine cytochrome c exhibits higher stability than the yeast protein, this provides a valuable opportunity to understand the role played by the invariant H26 residue in determining structure and stability.
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Affiliation(s)
- Federica Sinibaldi
- Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Università di Roma Tor Vergata, via Montpellier 1, 00133 Rome, Italy
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Sinibaldi F, Mei G, Polticelli F, Piro MC, Howes BD, Smulevich G, Santucci R, Ascoli F, Fiorucci L. ATP specifically drives refolding of non-native conformations of cytochrome c. Protein Sci 2005; 14:1049-58. [PMID: 15741329 PMCID: PMC2253445 DOI: 10.1110/ps.041069405] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Revised: 11/19/2004] [Accepted: 01/07/2005] [Indexed: 10/25/2022]
Abstract
An increasing body of evidence ascribes to misfolded forms of cytochrome c (cyt c) a role in pathophysiological events such as apoptosis and disease. Here, we examine the conformational changes induced by lipid binding to horse heart cyt c at pH 7 and study the ability of ATP (and other nucleotides) to refold several forms of unfolded cyt c such as oleic acid-bound cyt c, nicked cyt c, and acid denatured cyt c. The CD and fluorescence spectra demonstrate that cyt c unfolded by oleic acid has an intact secondary structure, and a disrupted tertiary structure and heme environment. Furthermore, evidence from the Soret CD, electronic absorption, and resonance Raman spectra indicates the presence of an equilibrium of at least two low-spin species having distinct heme-iron(III) coordination. As a whole, the data indicate that binding of cyt c to oleic acid leads to a partially unfolded conformation of the protein, resembling that typical of the molten globule state. Interestingly, the native conformation is almost fully recovered in the presence of ATP or dATP, while other nucleotides, such as GTP, are ineffective. Molecular modeling of ATP binding to cyt c and mutagenesis experiments show the interactions of phosphate groups with Lys88 and Arg91, with adenosine ring interaction with Glu62 explaining the unfavorable binding of GTP. The finding that ATP and dATP are unique among the nucleotides in being able to turn non-native states of cyt c back to native conformation is discussed in the light of cyt c involvement in cell apoptosis.
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Affiliation(s)
- Federica Sinibaldi
- Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Università di Roma Tor Vergata, via Montpellier 1, 00133 Rome, Italy
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