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Condino F, Crocco MC, Pirritano D, Petrone A, Del Giudice F, Guzzi R. A Linear Predictor Based on FTIR Spectral Biomarkers Improves Disease Diagnosis Classification: An Application to Multiple Sclerosis. J Pers Med 2023; 13:1596. [PMID: 38003911 PMCID: PMC10672539 DOI: 10.3390/jpm13111596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/02/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system that can lead to long-term disability. The diagnosis of MS is not simple and requires many instrumental and clinical tests. Sampling easily collected biofluids using spectroscopic approaches is becoming of increasing interest in the medical field to integrate and improve diagnostic procedures. Here we present a statistical approach where we combine a number of spectral biomarkers derived from the ATR-FTIR spectra of blood plasma samples of healthy control subjects and MS patients, to obtain a linear predictor useful for discriminating between the two groups of individuals. This predictor provides a simple tool in which the contribution of different molecular components is summarized and, as a result, the sensitivity (80%) and specificity (93%) of the identification are significantly improved compared to those obtained with typical classification algorithms. The strategy proposed can be very helpful when applied to the diagnosis of diseases whose presence is reflected in a minimal way in the analyzed biofluids (blood and its derivatives), as it is for MS as well as for other neurological disorders.
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Affiliation(s)
- Francesca Condino
- Department of Economics, Statistics and Finance ”Giovanni Anania”, University of Calabria, 87036 Rende, Italy;
| | - Maria Caterina Crocco
- STAR Research Infrastructure, University of Calabria, 87036 Rende, Italy;
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, Italy
| | - Domenico Pirritano
- SOC Neurologia, Azienda Ospedaliero-Universitaria Renato Dulbecco, 88100 Catanzaro, Italy;
- UOC Neurologia, Azienda Ospedaliera dell’Annunziata, 87100 Cosenza, Italy; (A.P.); (F.D.G.)
| | - Alfredo Petrone
- UOC Neurologia, Azienda Ospedaliera dell’Annunziata, 87100 Cosenza, Italy; (A.P.); (F.D.G.)
| | - Francesco Del Giudice
- UOC Neurologia, Azienda Ospedaliera dell’Annunziata, 87100 Cosenza, Italy; (A.P.); (F.D.G.)
- SOC Neurologia, Ospedale Jazzolino, Azienda Ospedaliera Provinciale, 89900 Vibo Valentia, Italy
| | - Rita Guzzi
- STAR Research Infrastructure, University of Calabria, 87036 Rende, Italy;
- CNR-NANOTEC, Department of Physics, University of Calabria, 87036 Rende, Italy
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2
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Guglielmelli A, Bartucci R, Rizzuti B, Palermo G, Guzzi R, Strangi G. The interaction of tryptophan enantiomers with model membranes is modulated by polar head type and physical state of phospholipids. Colloids Surf B Biointerfaces 2023; 224:113216. [PMID: 36848783 DOI: 10.1016/j.colsurfb.2023.113216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/29/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023]
Abstract
The mutual influence of chiral bioactive molecules and supramolecular assemblies is currently being studied in many research fields, including medical-pharmaceutical applications. Model membranes of phospholipids, such as the zwitterionic dipalmitoylphosphatidylcholine (DPPC) and the anionic dipalmitoylphosphatidylglycerol (DPPG), interact with a variety of chiral compounds that include amino acids. In this work, the interaction of tryptophan enantiomers, L-Trp and D-Trp, on DPPC and DPPG bilayers was investigated by using differential scanning calorimetry, attenuated total reflectance-Fourier transform infrared and spin-label electron spin resonance spectroscopies as well as molecular docking simulations. The results show that Trp enantiomers slightly perturb the bilayer thermotropic phase transitions. For both membranes, O atoms in the carbonyl groups have a propensity to act as acceptors of a (weak) hydrogen bond. The Trp chiral forms also promote formation of hydrogen bonds and/or hydration in the PO2- moiety of the phosphate group, especially for the DPPC bilayer. In contrast, they interact more closely with the glycerol group of DPPG polar head. Only for DPPC bilayers, both enantiomers increase the packing of the first hydrocarbon chain segments for temperatures through the gel state, whereas they do not affect the lipid chain order and mobility in the fluid state. The results are consistent with a Trp association in the upper region of the bilayers without permeation in the innermost hydrophobic region. The findings suggest that neutral and anionic lipid bilayers are differently sensitive to amino acid chirality.
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Affiliation(s)
- Alexa Guglielmelli
- Department of Physics, NLHT Lab., University of Calabria, 87036 Rende, Italy; CNR NANOTEC-Institute of Nanotechnology, SS Rende (CS), 87036 Rende, Italy
| | - Rosa Bartucci
- Department of Chemistry and Chemical Technologies, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, Italy.
| | - Bruno Rizzuti
- CNR NANOTEC-Institute of Nanotechnology, SS Rende (CS), 87036 Rende, Italy; Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, University of Zaragoza, 50018 Zaragoza, Spain
| | - Giovanna Palermo
- Department of Physics, NLHT Lab., University of Calabria, 87036 Rende, Italy; CNR NANOTEC-Institute of Nanotechnology, SS Rende (CS), 87036 Rende, Italy
| | - Rita Guzzi
- CNR NANOTEC-Institute of Nanotechnology, SS Rende (CS), 87036 Rende, Italy; Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, Italy
| | - Giuseppe Strangi
- Department of Physics, NLHT Lab., University of Calabria, 87036 Rende, Italy; CNR NANOTEC-Institute of Nanotechnology, SS Rende (CS), 87036 Rende, Italy; Department of Physics, Case Western Reserve University, 2076 Adelbert Rd, Cleveland, OH 44106 USA
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3
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Rocca C, De Bartolo A, Guzzi R, Crocco MC, Rago V, Romeo N, Perrotta I, De Francesco EM, Muoio MG, Granieri MC, Pasqua T, Mazza R, Boukhzar L, Lefranc B, Leprince J, Gallo Cantafio ME, Soda T, Amodio N, Anouar Y, Angelone T. Palmitate-Induced Cardiac Lipotoxicity Is Relieved by the Redox-Active Motif of SELENOT through Improving Mitochondrial Function and Regulating Metabolic State. Cells 2023; 12:cells12071042. [PMID: 37048116 PMCID: PMC10093731 DOI: 10.3390/cells12071042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/22/2023] [Accepted: 03/27/2023] [Indexed: 04/14/2023] Open
Abstract
Cardiac lipotoxicity is an important contributor to cardiovascular complications during obesity. Given the fundamental role of the endoplasmic reticulum (ER)-resident Selenoprotein T (SELENOT) for cardiomyocyte differentiation and protection and for the regulation of glucose metabolism, we took advantage of a small peptide (PSELT), derived from the SELENOT redox-active motif, to uncover the mechanisms through which PSELT could protect cardiomyocytes against lipotoxicity. To this aim, we modeled cardiac lipotoxicity by exposing H9c2 cardiomyocytes to palmitate (PA). The results showed that PSELT counteracted PA-induced cell death, lactate dehydrogenase release, and the accumulation of intracellular lipid droplets, while an inert form of the peptide (I-PSELT) lacking selenocysteine was not active against PA-induced cardiomyocyte death. Mechanistically, PSELT counteracted PA-induced cytosolic and mitochondrial oxidative stress and rescued SELENOT expression that was downregulated by PA through FAT/CD36 (cluster of differentiation 36/fatty acid translocase), the main transporter of fatty acids in the heart. Immunofluorescence analysis indicated that PSELT also relieved the PA-dependent increase in CD36 expression, while in SELENOT-deficient cardiomyocytes, PA exacerbated cell death, which was not mitigated by exogenous PSELT. On the other hand, PSELT improved mitochondrial respiration during PA treatment and regulated mitochondrial biogenesis and dynamics, preventing the PA-provoked decrease in PGC1-α and increase in DRP-1 and OPA-1. These findings were corroborated by transmission electron microscopy (TEM), revealing that PSELT improved the cardiomyocyte and mitochondrial ultrastructures and restored the ER network. Spectroscopic characterization indicated that PSELT significantly attenuated infrared spectral-related macromolecular changes (i.e., content of lipids, proteins, nucleic acids, and carbohydrates) and also prevented the decrease in membrane fluidity induced by PA. Our findings further delineate the biological significance of SELENOT in cardiomyocytes and indicate the potential of its mimetic PSELT as a protective agent for counteracting cardiac lipotoxicity.
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Affiliation(s)
- Carmine Rocca
- Cellular and Molecular Cardiovascular Pathophysiology Laboratory, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, 87036 Rende, Italy
| | - Anna De Bartolo
- Cellular and Molecular Cardiovascular Pathophysiology Laboratory, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, 87036 Rende, Italy
- UNIROUEN, Inserm U1239, Neuroendocrine, Endocrine and Germinal Differentiation and Communication (NorDiC), Rouen Normandie University, 76000 Mont-Saint-Aignan, France
| | - Rita Guzzi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, Italy
- CNR-NANOTEC, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Maria Caterina Crocco
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, Italy
- STAR Research Infrastructure, University of Calabria, Via Tito Flavio, 87036 Rende, Italy
| | - Vittoria Rago
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy
| | - Naomi Romeo
- Cellular and Molecular Cardiovascular Pathophysiology Laboratory, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, 87036 Rende, Italy
| | - Ida Perrotta
- Centre for Microscopy and Microanalysis (CM2), Department of Biology, Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, 87036 Rende, Italy
| | - Ernestina Marianna De Francesco
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95124 Catania, Italy
| | - Maria Grazia Muoio
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95124 Catania, Italy
| | - Maria Concetta Granieri
- Cellular and Molecular Cardiovascular Pathophysiology Laboratory, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, 87036 Rende, Italy
| | - Teresa Pasqua
- Department of Health Science, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy
| | - Rosa Mazza
- Cellular and Molecular Cardiovascular Pathophysiology Laboratory, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, 87036 Rende, Italy
| | - Loubna Boukhzar
- UNIROUEN, Inserm U1239, Neuroendocrine, Endocrine and Germinal Differentiation and Communication (NorDiC), Rouen Normandie University, 76000 Mont-Saint-Aignan, France
| | - Benjamin Lefranc
- UNIROUEN, Inserm U1239, Neuroendocrine, Endocrine and Germinal Differentiation and Communication (NorDiC), Rouen Normandie University, 76000 Mont-Saint-Aignan, France
- UNIROUEN, UMS-UAR HERACLES, PRIMACEN, Cell Imaging Platform of Normandy, Institute for Research and Innovation in Biomedicine (IRIB), 76183 Rouen, France
| | - Jérôme Leprince
- UNIROUEN, Inserm U1239, Neuroendocrine, Endocrine and Germinal Differentiation and Communication (NorDiC), Rouen Normandie University, 76000 Mont-Saint-Aignan, France
- UNIROUEN, UMS-UAR HERACLES, PRIMACEN, Cell Imaging Platform of Normandy, Institute for Research and Innovation in Biomedicine (IRIB), 76183 Rouen, France
| | | | - Teresa Soda
- Department of Health Science, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy
| | - Nicola Amodio
- Department of Experimental and Clinical Medicine, Magna Graecia University, 88100 Catanzaro, Italy
| | - Youssef Anouar
- UNIROUEN, Inserm U1239, Neuroendocrine, Endocrine and Germinal Differentiation and Communication (NorDiC), Rouen Normandie University, 76000 Mont-Saint-Aignan, France
- UNIROUEN, UMS-UAR HERACLES, PRIMACEN, Cell Imaging Platform of Normandy, Institute for Research and Innovation in Biomedicine (IRIB), 76183 Rouen, France
| | - Tommaso Angelone
- Cellular and Molecular Cardiovascular Pathophysiology Laboratory, Department of Biology, Ecology and Earth Sciences (DiBEST), University of Calabria, 87036 Rende, Italy
- National Institute of Cardiovascular Research (INRC), 40126 Bologna, Italy
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4
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Crocco MC, Moyano MFH, Annesi F, Bruno R, Pirritano D, Del Giudice F, Petrone A, Condino F, Guzzi R. ATR-FTIR spectroscopy of plasma supported by multivariate analysis discriminates multiple sclerosis disease. Sci Rep 2023; 13:2565. [PMID: 36782055 PMCID: PMC9924868 DOI: 10.1038/s41598-023-29617-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/07/2023] [Indexed: 02/15/2023] Open
Abstract
Multiple sclerosis (MS) is one of the most common neurodegenerative diseases showing various symptoms both of physical and cognitive type. In this work, we used attenuated total reflection Fourier transformed infrared (ATR-FTIR) spectroscopy to analyze plasma samples for discriminating MS patients from healthy control individuals, and identifying potential spectral biomarkers helping the diagnosis through a quick non-invasive blood test. The cohort of the study consists of 85 subjects, including 45 MS patients and 40 healthy controls. The differences in the spectral features both in the fingerprint region (1800-900 cm-1) and in the high region (3050-2800 cm-1) of the infrared spectra were highlighted also with the support of different chemometric methods, to capture the most significant wavenumbers for the differentiation. The results show an increase in the lipid/protein ratio in MS patients, indicating changes in the level (metabolism) of these molecular components in the plasma. Moreover, the multivariate tools provided a promising rate of success in the diagnosis, with 78% sensitivity and 83% specificity obtained through the random forest model in the fingerprint region. The MS diagnostic tools based on biomarkers identification on blood (and blood component, like plasma or serum) are very challenging and the specificity and sensitivity values obtained in this work are very encouraging. Overall, the results obtained suggest that ATR-FTIR spectroscopy on plasma samples, requiring minimal or no manipulation, coupled with statistical multivariate approaches, is a promising analytical tool to support MS diagnosis through the identification of spectral biomarkers.
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Affiliation(s)
- Maria Caterina Crocco
- Molecular Biophysics Laboratory, Department of Physics, University of Calabria, 87036, Rende, Italy
- STAR Research Infrastructure, University of Calabria, 87036, Rende, CS, Italy
| | | | | | - Rosalinda Bruno
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Rende, CS, Italy
| | - Domenico Pirritano
- Neurological and Stroke Unit, Multiple Sclerosis Clinic, Annunziata Hospital, 87100, Cosenza, Italy
- SOC Neurologia-Azienda Ospedaliera Pugliese-Ciaccio, 88100, Catanzaro, Italy
| | - Francesco Del Giudice
- Neurological and Stroke Unit, Multiple Sclerosis Clinic, Annunziata Hospital, 87100, Cosenza, Italy
- SOC Neurologia-Ospedale Jazzolino, Azienda Ospedaliera Provinciale, 89900, Vibo Valentia, Italy
| | - Alfredo Petrone
- Neurological and Stroke Unit, Multiple Sclerosis Clinic, Annunziata Hospital, 87100, Cosenza, Italy
| | - Francesca Condino
- Department of Economics, Statistics and Finance "Giovanni Anania", University of Calabria, Arcavacata di Rende, CS, Italy
| | - Rita Guzzi
- Molecular Biophysics Laboratory, Department of Physics, University of Calabria, 87036, Rende, Italy.
- CNR-Nanotec Rende, Via P. Bucci, 87036, Rende, Italy.
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5
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Candreva A, Parisi F, Bartucci R, Guzzi R, Di Maio G, Scarpelli F, Aiello I, Godbert N, La Deda M. Synthesis and Characterization of Hyper‐Branched Nanoparticles with Magnetic and Plasmonic Properties. ChemistrySelect 2022. [DOI: 10.1002/slct.202201375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Angela Candreva
- Department of Chemistry and Chemical Technologies University of Calabria 87036 Rende CS Italy
- CNR-NANOTEC Istituto di Nanotecnologia U.O.S Cosenza (CS) 87036 Rende Italy
| | - Francesco Parisi
- Department of Chemistry and Chemical Technologies University of Calabria 87036 Rende CS Italy
| | - Rosa Bartucci
- Department of Chemistry and Chemical Technologies University of Calabria 87036 Rende CS Italy
- Department of Physics Molecular Biophysics Laboratory University of Calabria 87036 Rende CS Italy
| | - Rita Guzzi
- CNR-NANOTEC Istituto di Nanotecnologia U.O.S Cosenza (CS) 87036 Rende Italy
- Department of Physics Molecular Biophysics Laboratory University of Calabria 87036 Rende CS Italy
| | - Giuseppe Di Maio
- Department of Chemistry and Chemical Technologies University of Calabria 87036 Rende CS Italy
| | - Francesca Scarpelli
- Department of Chemistry and Chemical Technologies University of Calabria 87036 Rende CS Italy
| | - Iolinda Aiello
- Department of Chemistry and Chemical Technologies University of Calabria 87036 Rende CS Italy
- CNR-NANOTEC Istituto di Nanotecnologia U.O.S Cosenza (CS) 87036 Rende Italy
| | - Nicolas Godbert
- Department of Chemistry and Chemical Technologies University of Calabria 87036 Rende CS Italy
| | - Massimo La Deda
- Department of Chemistry and Chemical Technologies University of Calabria 87036 Rende CS Italy
- CNR-NANOTEC Istituto di Nanotecnologia U.O.S Cosenza (CS) 87036 Rende Italy
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6
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Guzzi R, Bartucci R. Interactive multiple binding of oleic acid, warfarin and ibuprofen with human serum albumin revealed by thermal and fluorescence studies. Eur Biophys J 2022; 51:41-49. [PMID: 35048131 DOI: 10.1007/s00249-021-01582-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/23/2021] [Accepted: 12/04/2021] [Indexed: 06/14/2023]
Abstract
Human serum albumin binds a wide variety of drugs with different structure and affinity to two main binding sites, drug site 1 (DS1) and drug site 2 (DS2), which partially or totally overlap with fatty acid (FA) sites. Although multiple binding sites are available for endogenous compounds, FAs are the primary physiological ligands of albumin and their competition in the occupancy of DS1 and DS2 affects the binding of exogenous molecules, with a possible impact on drug delivery. In this work, we have investigated the simultaneous binding of oleic acid, warfarin and ibuprofen to albumin using differential scanning calorimetry and fluorescence to evaluate the impact on the conformational stability of the protein. The two drugs are widely used for their anticoagulant (warfarin) and anti-inflammatory (ibuprofen) properties, and can be also considered as site markers to probe DS1 and DS2, respectively. Oleic acid is one of the most important fatty acids from a physiological point of view for its role as a source of energy for cells, and also it binds albumin with the highest association constant. When complexed with oleic acid the calorimetric profile of albumin shows a biphasic trend whose line shape depends on the ligand concentration. The binding capacity of either warfarin or ibuprofen to albumin is modulated by oleate molecules in a concentration-dependent mode being synergic cooperative (warfarin) or competitive-like (ibuprofen). The overall results provide insights on the dynamics of albumin/ligands complex, which in turn may have important pharmacokinetic and pharmacodynamic implications.
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Affiliation(s)
- Rita Guzzi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036, Rende, Italy.
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036, Rende, Italy.
| | - Rosa Bartucci
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036, Rende, Italy
- Department of Chemistry and Chemical Technologies, University of Calabria, 87036, Rende, Italy
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7
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Pacheco-Garcia JL, Loginov D, Rizzuti B, Vankova P, Neira JL, Kavan D, Mesa-Torres N, Guzzi R, Man P, Pey AL. A single evolutionarily divergent mutation determines the different FAD-binding affinities of human and rat NQO1 due to site-specific phosphorylation. FEBS Lett 2021; 596:29-41. [PMID: 34817874 DOI: 10.1002/1873-3468.14238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 12/13/2022]
Abstract
The phosphomimetic mutation S82D in the cancer-associated, FAD-dependent human NADP(H):quinone oxidoreductase 1 (hNQO1) causes a decrease in flavin-adenine dinucleotide-binding affinity and intracellular stability. We test in this work whether the evolutionarily recent neutral mutation R80H in the vicinity of S82 may alter the strong functional effects of S82 phosphorylation through electrostatic interactions. We show using biophysical and bioinformatic analyses that the reverse mutation H80R prevents the effects of S82D phosphorylation on hNQO1 by modulating the local stability. Consistently, in rat NQO1 (rNQO1) which contains R80, the effects of phosphorylation were milder, resembling the behaviour found in hNQO1 when this residue was humanized in rNQO1 (by the R80H mutation). Thus, apparently neutral and evolutionarily divergent mutations may determine the functional response of mammalian orthologues towards phosphorylation.
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Affiliation(s)
| | - Dmitry Loginov
- Institute of Microbiology of the Czech Academy of Sciences, BioCeV, Praha, Czech Republic
| | - Bruno Rizzuti
- CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, Rende, Italy.,Instituto de Biocomputación y Física de los Sistemas Complejos (BIFI), Zaragoza, Spain
| | - Pavla Vankova
- Institute of Biotechnology of the Czech Academy of Sciences, BioCeV, Vestec, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jose L Neira
- Instituto de Biocomputación y Física de los Sistemas Complejos (BIFI), Zaragoza, Spain.,Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche, Spain
| | - Daniel Kavan
- Institute of Microbiology of the Czech Academy of Sciences, BioCeV, Praha, Czech Republic
| | - Noel Mesa-Torres
- Departamento de Química Física, Facultad de Ciencias, Universidad de Granada, Spain
| | - Rita Guzzi
- CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, Rende, Italy.,Molecular Biophysics Laboratory, Department of Physics, University of Calabria, Rende, Italy
| | - Petr Man
- Institute of Microbiology of the Czech Academy of Sciences, BioCeV, Praha, Czech Republic
| | - Angel L Pey
- Departamento de Química Física, Unidad de Excelencia de Química aplicada a Biomedicina y Medioambiente e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, Spain
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8
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Cirillo F, Pellegrino M, Talia M, Perrotta ID, Rigiracciolo DC, Spinelli A, Scordamaglia D, Muglia L, Guzzi R, Miglietta AM, De Francesco EM, Belfiore A, Maggiolini M, Lappano R. Estrogen receptor variant ERα46 and insulin receptor drive in primary breast cancer cells growth effects and interleukin 11 induction prompting the motility of cancer-associated fibroblasts. Clin Transl Med 2021; 11:e516. [PMID: 34841688 PMCID: PMC8567034 DOI: 10.1002/ctm2.516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/21/2021] [Accepted: 07/20/2021] [Indexed: 02/06/2023] Open
Abstract
Among the prognostic and predictive biomarkers of breast cancer (BC), the role of estrogen receptor (ER)α wild-type has been acknowledged, although the action of certain ERα splice variants has not been elucidated. Insulin/insulin receptor (IR) axis has also been involved in the progression and metastasis of BC. For instance, hyperinsulinemia, which is often associated with obesity and type 2 diabetes, may be a risk factor for BC. Similarly, an aberrant expression of IR or its hyperactivation may correlate with aggressive BC phenotypes. In the present study, we have shown that a novel naturally immortalized BC cell line (named BCAHC-1) is characterized by a unique expression of 46 kDa ERα splice variant (ERα46) along with IR. Moreover, we have shown that a multifaceted crosstalk between ERα46 and IR occurs in BCAHC-1 cells upon estrogen and insulin exposure for growth and pulmonary metastasis. Through high-throughput RNA sequencing analysis, we have also found that the cytokine interleukin-11 (IL11) is the main factor linking BCAHC-1 cells to breast cancer-associated fibroblasts (CAFs). In particular, we have found that IL11 induced by estrogens and insulin in BCAHC-1 cells regulates pro-tumorigenic genes of the "extracellular matrix organization" signaling pathway, such as ICAM-1 and ITGA5, and promotes both migratory and invasive features in breast CAFs. Overall, our results may open a new scientific avenue to identify additional prognostic and therapeutic targets in BC.
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Affiliation(s)
- Francesca Cirillo
- Department of PhysicsUniversity of CalabriaRendeItaly
- Department of Pharmacy, Health and Nutritional SciencesUniversity of CalabriaRendeItaly
| | - Michele Pellegrino
- Department of Pharmacy, Health and Nutritional SciencesUniversity of CalabriaRendeItaly
| | - Marianna Talia
- Department of Pharmacy, Health and Nutritional SciencesUniversity of CalabriaRendeItaly
| | - Ida Daniela Perrotta
- Centre for Microscopy and Microanalysis, Transmission Electron Microscopy Laboratory, and Department of Biology, Ecology and Earth SciencesUniversity of CalabriaRendeItaly
| | | | - Asia Spinelli
- Department of Pharmacy, Health and Nutritional SciencesUniversity of CalabriaRendeItaly
| | - Domenica Scordamaglia
- Department of Pharmacy, Health and Nutritional SciencesUniversity of CalabriaRendeItaly
| | - Lucia Muglia
- Department of Pharmacy, Health and Nutritional SciencesUniversity of CalabriaRendeItaly
| | - Rita Guzzi
- Department of PhysicsUniversity of CalabriaRendeItaly
| | | | | | - Antonino Belfiore
- Department of Clinical and Experimental Medicine, University of CataniaGaribaldi‐Nesima HospitalCataniaItaly
| | - Marcello Maggiolini
- Department of Pharmacy, Health and Nutritional SciencesUniversity of CalabriaRendeItaly
| | - Rosamaria Lappano
- Department of Pharmacy, Health and Nutritional SciencesUniversity of CalabriaRendeItaly
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9
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Annesi F, Hermoso-Durán S, Rizzuti B, Bruno R, Pirritano D, Petrone A, Del Giudice F, Ojeda J, Vega S, Sanchez-Gracia O, Velazquez-Campoy A, Abian O, Guzzi R. Thermal Liquid Biopsy (TLB) of Blood Plasma as a Potential Tool to Help in the Early Diagnosis of Multiple Sclerosis. J Pers Med 2021; 11:jpm11040295. [PMID: 33924346 PMCID: PMC8069382 DOI: 10.3390/jpm11040295] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/31/2021] [Accepted: 04/09/2021] [Indexed: 12/21/2022] Open
Abstract
Background: Multiple sclerosis (MS) is frequently characterized by a variety of clinical signs, often exhibiting little specificity. The diagnosis requires a combination of medical observations and instrumental tests, and any support for its objective assessment is helpful. Objective: Herein, we describe the application of thermal liquid biopsy (TLB) of blood plasma samples, a methodology for predicting the occurrence of MS with a noninvasive, quick blood test. Methods: TLB allows one to define an index (TLB score), which provides information about overall real-time alterations in plasma proteome that may be indicative of MS. Results: This pilot study, based on 85 subjects (45 MS patients and 40 controls), showed good performance indexes (sensitivity and specificity both around 70%). The diagnostic methods better discriminate between early stage and low-burden MS patients, and it is not influenced by gender, age, or assumption of therapeutic drugs. TLB is more accurate for patients having low disability level (≤ 3.0, measured by the expanded disability status scale, EDSS) and a relapsing–remitting diagnosis. Conclusion: Our results suggest that TLB can be applied to MS, especially in an initial phase of the disease when diagnosis is difficult and yet more important (in such cases, accuracy of prediction is close to 80%), as well as in personalized patient periodic monitoring. The next step will be determining its utility in differentiating between MS and other disorders, in particular in inflammatory diseases.
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Affiliation(s)
- Ferdinanda Annesi
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy; (F.A.); (B.R.)
| | - Sonia Hermoso-Durán
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (S.H.-D.); (S.V.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy; (F.A.); (B.R.)
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (S.H.-D.); (S.V.); (A.V.-C.)
| | - Rosalinda Bruno
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy;
| | - Domenico Pirritano
- Neurological and Stroke Unit, Multiple Sclerosis Clinic, Annunziata Hospital, 87100 Cosenza, Italy; (D.P.); (A.P.); (F.D.G.)
| | - Alfredo Petrone
- Neurological and Stroke Unit, Multiple Sclerosis Clinic, Annunziata Hospital, 87100 Cosenza, Italy; (D.P.); (A.P.); (F.D.G.)
| | - Francesco Del Giudice
- Neurological and Stroke Unit, Multiple Sclerosis Clinic, Annunziata Hospital, 87100 Cosenza, Italy; (D.P.); (A.P.); (F.D.G.)
| | - Jorge Ojeda
- Department of Statistical Methods, Universidad de Zaragoza, 50009 Zaragoza, Spain;
| | - Sonia Vega
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (S.H.-D.); (S.V.); (A.V.-C.)
| | | | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (S.H.-D.); (S.V.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Fundación ARAID, Gobierno de Aragón, 50009 Zaragoza, Spain
| | - Olga Abian
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (S.H.-D.); (S.V.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain
- Correspondence: (O.A.); (R.G.); Tel.: +34-876-555417 (O.A.); +39-0984-406077 (R.G.)
| | - Rita Guzzi
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy; (F.A.); (B.R.)
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, Italy
- Correspondence: (O.A.); (R.G.); Tel.: +34-876-555417 (O.A.); +39-0984-406077 (R.G.)
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10
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Aloi E, Rizzuti B, Guzzi R, Bartucci R. Binding of warfarin differently affects the thermal behavior and chain packing of anionic, zwitterionic and cationic lipid membranes. Arch Biochem Biophys 2020; 694:108599. [PMID: 32979389 DOI: 10.1016/j.abb.2020.108599] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 09/06/2020] [Accepted: 09/22/2020] [Indexed: 11/16/2022]
Abstract
Warfarin is a coumarin derivative drug widely used for its anticoagulant properties. The interaction of warfarin with fully hydrated lipid bilayers has been studied by combining differential scanning calorimetry, spectrophotometry, electron spin resonance of chain-labelled lipids and molecular docking. Bilayers formed by lipids with different chemico-physical properties were considered, namely dimyristoyl-phosphatidylcholine (DMPC), dimyristoyl-phosphatidylglycerol (DMPG), and dioleoyltrimethyl-ammoniumpropane (DOTAP). We observed in all cases the binding of warfarin in proximity of the surface of the bilayers, leading to a variety of distinct effects on key molecular properties of the membranes. The drug associates with the lipid bilayers in the deprotonated open chain form, with an association constant similar for DMPC and DMPG (1.27·104 and 2.82·104 M-1, respectively) and lower for DOTAP (0.46·104 M-1). In DMPC bilayers, which are zwitterionic and with saturated symmetrical chains, warfarin at 10 mol% suppresses the pre-transition, slightly stabilizes the fluid state and reduces the cooperativity of the main transition. Moreover, it alters the lateral packing density of the chain segments close to the polar/apolar interface at any temperature through the gel phase. In anionic DMPG bilayers, the drug slightly perturbs the thermotropic phase behavior, and at 10 mol% markedly loosens the compact gel phase packing of the first chain segments. In cationic DOTAP bilayers, possessing unsaturated acyl chains, the drug induces a slightly higher degree of order and motional restriction in the outer hydrocarbon region in the frozen state. In all cases, as a surface adsorbed molecule, warfarin does not affect the segmental chain order and dynamics for temperatures in the fluid phase. The overall results provide an outline of the action of warfarin on membranes formed by lipids of different types.
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Affiliation(s)
- Erika Aloi
- Department of Physics and Molecular Biophysics Laboratory, University of Calabria, 87036, Rende, Italy
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Rende, 87036, Italy
| | - Rita Guzzi
- Department of Physics and Molecular Biophysics Laboratory, University of Calabria, 87036, Rende, Italy; CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Rende, 87036, Italy
| | - Rosa Bartucci
- Department of Chemistry and Chemical Technologies and Molecular Biophysics Laboratory, University of Calabria, 87036, Rende, Italy.
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11
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Lappano R, Talia M, Cirillo F, Rigiracciolo DC, Scordamaglia D, Guzzi R, Miglietta AM, De Francesco EM, Belfiore A, Sims AH, Maggiolini M. The IL1β-IL1R signaling is involved in the stimulatory effects triggered by hypoxia in breast cancer cells and cancer-associated fibroblasts (CAFs). J Exp Clin Cancer Res 2020; 39:153. [PMID: 32778144 PMCID: PMC7418191 DOI: 10.1186/s13046-020-01667-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 08/04/2020] [Indexed: 12/11/2022]
Abstract
Background Hypoxia plays a relevant role in tumor-related inflammation toward the metastatic spread and cancer aggressiveness. The pro-inflammatory cytokine interleukin-1β (IL-β) and its cognate receptor IL1R1 contribute to the initiation and progression of breast cancer determining pro-tumorigenic inflammatory responses. The transcriptional target of the hypoxia inducible factor-1α (HIF-1α) namely the G protein estrogen receptor (GPER) mediates a feedforward loop coupling IL-1β induction by breast cancer-associated fibroblasts (CAFs) to IL1R1 expression by breast cancer cells toward the regulation of target genes and relevant biological responses. Methods In order to ascertain the correlation of IL-β with HIF-1α and further hypoxia-related genes in triple-negative breast cancer (TNBC) patients, a bioinformatics analysis was performed using the information provided by The Invasive Breast Cancer Cohort of The Cancer Genome Atlas (TCGA) project and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets. Gene expression correlation, statistical analysis and gene set enrichment analysis (GSEA) were carried out with R studio packages. Pathway enrichment analysis was evaluated with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. TNBC cells and primary CAFs were used as model system. The molecular mechanisms implicated in the regulation of IL-1β by hypoxia toward a metastatic gene expression profile and invasive properties were assessed performing gene and protein expression studies, PCR arrays, gene silencing and immunofluorescence analysis, co-immunoprecipitation and ChiP assays, ELISA, cell spreading, invasion and spheroid formation. Results We first determined that IL-1β expression correlates with the levels of HIF-1α as well as with a hypoxia-related gene signature in TNBC patients. Next, we demonstrated that hypoxia triggers a functional liaison among HIF-1α, GPER and the IL-1β/IL1R1 signaling toward a metastatic gene signature and a feed-forward loop of IL-1β that leads to proliferative and invasive responses in TNBC cells. Furthermore, we found that the IL-1β released in the conditioned medium of TNBC cells exposed to hypoxic conditions promotes an invasive phenotype of CAFs. Conclusions Our data shed new light on the role of hypoxia in the activation of the IL-1β/IL1R1 signaling, which in turn triggers aggressive features in both TNBC cells and CAFs. Hence, our findings provide novel evidence regarding the mechanisms through which the hypoxic tumor microenvironment may contribute to breast cancer progression and suggest further targets useful in more comprehensive therapeutic strategies.
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Affiliation(s)
- Rosamaria Lappano
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Rende, Italy.
| | - Marianna Talia
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Rende, Italy
| | - Francesca Cirillo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Rende, Italy
| | | | - Domenica Scordamaglia
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Rende, Italy
| | - Rita Guzzi
- Department of Physics, University of Calabria, 87036, Rende, Italy
| | | | - Ernestina Marianna De Francesco
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95122, Catania, Italy
| | - Antonino Belfiore
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95122, Catania, Italy
| | - Andrew H Sims
- MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, EH4 2XR, UK
| | - Marcello Maggiolini
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Rende, Italy.
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12
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Grande F, Occhiuzzi MA, Lappano R, Cirillo F, Guzzi R, Garofalo A, Jacquot Y, Maggiolini M, Rizzuti B. Computational Approaches for the Discovery of GPER Targeting Compounds. Front Endocrinol (Lausanne) 2020; 11:517. [PMID: 32849301 PMCID: PMC7417359 DOI: 10.3389/fendo.2020.00517] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/26/2020] [Indexed: 12/12/2022] Open
Abstract
Estrogens exert a panel of biological activities mainly through the estrogen receptors α and β, which belong to the nuclear receptor superfamily. Diverse studies have shown that the G protein-coupled estrogen receptor 1 (GPER, previously known as GPR30) also mediates the multifaceted effects of estrogens in numerous pathophysiological events, including neurodegenerative, immune, metabolic, and cardiovascular disorders and the progression of different types of cancer. In particular, GPER is implicated in hormone-sensitive tumors, albeit diverse issues remain to be deeply investigated. As such, this receptor may represent an appealing target for therapeutics in different diseases. The yet unavailable complete GPER crystallographic structure, and its relatively low sequence similarity with the other members of the G protein-coupled receptor (GPCR) family, hamper the possibility to discover compounds able to modulate GPER activity. Consequently, a reliable molecular model of this receptor is required for the design of suitable ligands. To date, convergent approaches involving structure-based drug design and virtual ligand screening have led to the identification of several GPER selective ligands, thus providing important information regarding its mode of action and function. In this survey, we summarize results obtained through computer-aided techniques devoted to the assessment of GPER ligands toward their usefulness in innovative treatments of different diseases.
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Affiliation(s)
- Fedora Grande
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Maria A. Occhiuzzi
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Rosamaria Lappano
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Francesca Cirillo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
- Department of Physics, University of Calabria, Rende, Italy
| | - Rita Guzzi
- Department of Physics, University of Calabria, Rende, Italy
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Rende, Italy
| | - Antonio Garofalo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Yves Jacquot
- Cibles Thérapeutiques et Conception de Médicaments (CiTCoM), CNRS UMR 8038, INSERM U1268, Faculté de Pharmacie de Paris, Université de Paris, Paris, France
| | - Marcello Maggiolini
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Rende, Italy
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13
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Liguori PF, Ghedini M, La Deda M, Godbert N, Parisi F, Guzzi R, Ionescu A, Aiello I. Electrochromic behaviour of Ir(iii) bis-cyclometalated 1,2-dioxolene tetra-halo complexes: fully reversible catecholate/semiquinone redox switches. Dalton Trans 2020; 49:2628-2635. [PMID: 32039433 DOI: 10.1039/c9dt04848k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neutral cyclometalated Ir(iii) complexes of general formula [Ir(ppy)2(O^O)squi], where ppy = 2-phenylpyridine and (O^O)squi = TBC (tetrabromocatechol) or TCC (tetrachlorocatechol) in their semiquinone (squi) monoanionic redox state, were synthesized by chemically oxidizing the anionic parent complexes NBu4[Ir(ppy)2(O^O)cat], in which (O^O)cat represents the corresponding ancillary dioxolene ligand in its dianionic catecholate (cat) redox state. This chemical oxidation leads to the modification of both the photophysical and the magnetic properties of the complexes. While the NBu4[Ir(ppy)2(O^O)cat] complexes are diamagnetic (D) and yellow-orange solids, the corresponding oxidized complexes [Ir(ppy)2(O^O)squi] display paramagnetic (P) properties and are characterized by a dark-green color. The conversion between the two forms (squi vs. cat) is electrochemically and chemically fully reversible. Indeed, the anionic NBu4[Ir(ppy)2(O^O)cat] complexes are quantitatively restored by chemical reduction of the neutral [Ir(ppy)2(O^O)squi] parents. These complexes therefore represent interesting redox based switches between multi-parameter states since they allow switching from a neutral paramagnetic to an anionic diamagnetic form together with a significant change in chromicity. Taking advantage of the significant color difference between the oxidized and the reduced form, an electrochromic cell was prepared with [Ir(ppy)2(TBC)squi] and its spectroelectrochemical properties are reported.
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Affiliation(s)
- Paola Francesca Liguori
- MAT_InLAB and LASCAMM - CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy.
| | - Mauro Ghedini
- MAT_InLAB and LASCAMM - CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy. and CNR-NANOTEC, Istituto di Nanotecnologia U.O.S. Cosenza, 87036 Arcavacata di Rende (CS), Italy
| | - Massimo La Deda
- MAT_InLAB and LASCAMM - CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy. and CNR-NANOTEC, Istituto di Nanotecnologia U.O.S. Cosenza, 87036 Arcavacata di Rende (CS), Italy
| | - Nicolas Godbert
- MAT_InLAB and LASCAMM - CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy. and CNR-NANOTEC, Istituto di Nanotecnologia U.O.S. Cosenza, 87036 Arcavacata di Rende (CS), Italy
| | - Francesco Parisi
- MAT_InLAB and LASCAMM - CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy.
| | - Rita Guzzi
- CNR-NANOTEC, Istituto di Nanotecnologia U.O.S. Cosenza, 87036 Arcavacata di Rende (CS), Italy and Dipartimento di Fisica, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy
| | - Andreea Ionescu
- MAT_InLAB and LASCAMM - CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy.
| | - Iolinda Aiello
- MAT_InLAB and LASCAMM - CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy. and CNR-NANOTEC, Istituto di Nanotecnologia U.O.S. Cosenza, 87036 Arcavacata di Rende (CS), Italy
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Ricciardi L, Guzzi R, Rizzuti B, Ionescu A, Aiello I, Ghedini M, La Deda M. Anionic versus neutral Pt (II) complexes: The relevance of the charge for human serum albumin binding. J Inorg Biochem 2020; 206:111024. [PMID: 32070915 DOI: 10.1016/j.jinorgbio.2020.111024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/30/2020] [Accepted: 02/09/2020] [Indexed: 10/25/2022]
Abstract
The focus of this work is pointing out the different behavior of two structurally related Pt(II) complexes, the anionic cyclometalated NBu4[(Bzq)Pt(Thio)], 1 and the neutral [(Phen)Pt(Thio)], 2, (Bzq = benzo[h]quinoline, Phen = 1,10-phenantroline, Thio = 1,2-benzenedithiolate), on the interaction with human serum albumin (HSA), a key drug-delivery protein in the bloodstream. Being very limited the number of anionic Pt(II) complexes reported to date, this is a pioneering example of report on a protein-ligand interaction involving a negatively charged platinum compound. The study was carried out by using fluorescence spectroscopy, differential scanning calorimetry and molecular docking simulations. The results revealed a strong binding affinity between the anionic compound and the protein, whereas a weak/moderate binding interaction was highlighted for the neutral one. Comparative studies with site specific ligands (warfarin and ibuprofen), allowed us to identify the protein binding sites of the two compounds. The work aims to shed light on the relevance of the charge in designing new drugs with a favorable binding affinity for HSA, which strongly contributes to influence their pharmacological and toxicological profile.
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Affiliation(s)
- Loredana Ricciardi
- CNR NANOTEC - Institute of Nanotechnology, UOS Cosenza, 87036 Arcavacata di Rende, CS, Italy.
| | - Rita Guzzi
- CNR NANOTEC - Institute of Nanotechnology, UOS Cosenza, 87036 Arcavacata di Rende, CS, Italy; Department of Physics, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Bruno Rizzuti
- CNR NANOTEC - Institute of Nanotechnology, UOS Cosenza, 87036 Arcavacata di Rende, CS, Italy
| | - Andreea Ionescu
- MAT_InLAB, Department of Chemistry and Chemical Technology, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Iolinda Aiello
- CNR NANOTEC - Institute of Nanotechnology, UOS Cosenza, 87036 Arcavacata di Rende, CS, Italy; MAT_InLAB, Department of Chemistry and Chemical Technology, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Mauro Ghedini
- CNR NANOTEC - Institute of Nanotechnology, UOS Cosenza, 87036 Arcavacata di Rende, CS, Italy; MAT_InLAB, Department of Chemistry and Chemical Technology, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Massimo La Deda
- CNR NANOTEC - Institute of Nanotechnology, UOS Cosenza, 87036 Arcavacata di Rende, CS, Italy; MAT_InLAB, Department of Chemistry and Chemical Technology, University of Calabria, 87036 Arcavacata di Rende, CS, Italy.
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Rizzuti B, Bartucci R, Guzzi R. Effects of Polar Head Nature and Tail Length of Single-Chain Lipids on the Conformational Stability of β-Lactoglobulin. J Phys Chem B 2020; 124:944-952. [PMID: 31968169 DOI: 10.1021/acs.jpcb.9b09925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Interaction between β-lactoglobulin and single-chain lipids, differing for either the length of the aliphatic chain or the molecular properties of the headgroup, was investigated at neutral and acidic pH to determine the impact on the thermal stability of the protein. Differential scanning calorimetry results with different fatty acids (from C10:0 to C18:0) show a correlation of both melting temperature and unfolding enthalpy of the protein with the ligand binding affinity, and the maximum effect was found for palmitic acid (PLM). The influence of the lipid polar head was investigated by comparing PLM with lyso-palmitoylphosphatidylcholine (LPC), which possesses the same aliphatic chain. At neutral pH, the stabilizing effect of LPC is less favorable compared to PLM. However, fluorescence results revealed that LPC can bind into the protein calyx even at acidic pH, at variance with fatty acids. Molecular dynamics simulations indicated that this difference is due to the ability of the polar head of LPC to interact with the protein loop that regulates the shift (Tanford transition) between open and closed state of the binding site of β-lactoglobulin. The results provide a rationale for how a ligand has the ability to access the protein active site at acidic conditions by overcoming the Tanford transition, and they demonstrate that β-lactoglobulin can deliver ligands with tailored properties of the polar head in a wide pH range.
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Affiliation(s)
- Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics , University of Calabria , 87036 Rende , Italy
| | - Rosa Bartucci
- Department of Chemistry and Chemical Technologies and Molecular Biophysics Laboratory , University of Calabria , 87036 Rende , Italy
| | - Rita Guzzi
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics , University of Calabria , 87036 Rende , Italy.,Department of Physics, Molecular Biophysics Laboratory , University of Calabria , 87036 Rende , Italy
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16
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Aloi E, Guzzi R, Bartucci R. Unsaturated lipid bilayers at cryogenic temperature: librational dynamics of chain-labeled lipids from pulsed and CW-EPR. Phys Chem Chem Phys 2019; 21:18699-18705. [PMID: 31423504 DOI: 10.1039/c9cp03318a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fully hydrated bilayers of monounsaturated palmitoyloleoylphosphatidylcholine (POPC) and diunsaturated dioleoylphosphatidylcholine (DOPC) lipids have low main phase transition temperatures (271 K for POPC and 253 K for DOPC). Two-pulse echo detected spectra, combined with continuous wave electron paramagnetic resonance spectroscopy, are employed to study the low-temperature lamellar phases of the POPC and DOPC unsaturated bilayers that are usually studied in the fluid state. Phosphatidylcholine spin-labeled at C-5 and C-16 carbon atom positions along the acyl chain were used and the temperature varied over the range 77-270 K. Segmental chain librational oscillations of small amplitude and with correlation time in the subnanosecond to nanosecond range are found in both membranes. The mean-square angular amplitude, α2, of librations increases with temperature, is larger close to the bilayer midplane than close to the first acyl chain segments, and is larger in diunsaturated than in monounsaturated bilayers. In the inner hydrocarbon region of both lipid matrices, α2 increases first slowly and linearly with temperature and then more rapidly, and a dynamical transition is detected in the range 190-210 K. Compared to dipalmitoylphosphatidylcholine bilayers of fully saturated symmetric chain lipids, the presence of double bonds in the acyl chain enhances the intensity of librational motion which is characterized by larger angular variations at the terminal methyl ends. These findings highlight biophysical properties of unsaturated bilayers in the frozen state, including a detailed characterization of segmental chain dynamics and the evidence of a dynamical transition that appears to be a generic feature in hydrated macromolecular systems. These results can also be relevant in regulating membrane physical properties and function at higher physiological temperatures.
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Affiliation(s)
- Erika Aloi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria, 87036 Rende, Italy
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Cirillo F, Lappano R, Bruno L, Rizzuti B, Grande F, Guzzi R, Briguori S, Miglietta AM, Nakajima M, Di Martino MT, Maggiolini M. AHR and GPER mediate the stimulatory effects induced by 3-methylcholanthrene in breast cancer cells and cancer-associated fibroblasts (CAFs). J Exp Clin Cancer Res 2019; 38:335. [PMID: 31370872 PMCID: PMC6676524 DOI: 10.1186/s13046-019-1337-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/23/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND The chemical carcinogen 3-methylcholanthrene (3MC) binds to the aryl hydrocarbon receptor (AHR) that regulates the expression of cytochrome P450 (CYP) enzymes as CYP1B1, which is involved in the oncogenic activation of environmental pollutants as well as in the estrogen biosynthesis and metabolism. 3MC was shown to induce estrogenic responses binding to the estrogen receptor (ER) α and stimulating a functional interaction between AHR and ERα. Recently, the G protein estrogen receptor (GPER) has been reported to mediate certain biological responses induced by endogenous estrogens and environmental compounds eliciting an estrogen-like activity. METHODS Molecular dynamics and docking simulations were performed to evaluate the potential of 3MC to interact with GPER. SkBr3 breast cancer cells and cancer-associated fibroblasts (CAFs) derived from breast tumor patients were used as model system. Real-time PCR and western blotting analysis were performed in order to evaluate the activation of transduction mediators as well as the mRNA and protein levels of CYP1B1 and cyclin D1. Co-immunoprecipitation studies were performed in order to explore the potential of 3MC to trigger the association of GPER with AHR and EGFR. Luciferase assays were carried out to determine the activity of CYP1B1 promoter deletion constructs upon 3MC exposure, while the nuclear shuttle of AHR induced by 3MC was assessed through confocal microscopy. Cell proliferation stimulated by 3MC was determined as biological counterpart of the aforementioned experimental assays. The statistical analysis was performed by ANOVA. RESULTS We first ascertained by docking simulations the ability of 3MC to interact with GPER. Thereafter, we established that 3MC activates the EGFR/ERK/c-Fos transduction signaling through both AHR and GPER in SkBr3 cells and CAFs. Then, we found that these receptors are involved in the up-regulation of CYP1B1 and cyclin D1 as well as in the stimulation of growth responses induced by 3MC. CONCLUSIONS In the present study we have provided novel insights regarding the molecular mechanisms by which 3MC may trigger a physical and functional interaction between AHR and GPER, leading to the stimulation of both SkBr3 breast cancer cells and CAFs. Altogether, our results indicate that 3MC may engage both GPER and AHR transduction pathways toward breast cancer progression.
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Affiliation(s)
- Francesca Cirillo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Cosenza, Rende, Italy
| | - Rosamaria Lappano
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Cosenza, Rende, Italy
| | - Leonardo Bruno
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036, Rende, Italy
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF. Cal and Department of Physics, University of Calabria, 87036, Rende, Italy
| | - Fedora Grande
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Cosenza, Rende, Italy
| | - Rita Guzzi
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF. Cal and Department of Physics, University of Calabria, 87036, Rende, Italy.,Molecular Biophysics Laboratory, Department of Physics, University of Calabria, 87036, Rende, Italy
| | - Sara Briguori
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Cosenza, Rende, Italy
| | | | - Miki Nakajima
- Drug Metabolism and Toxicology, WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
| | - Maria Teresa Di Martino
- Department of Experimental and Clinical Medicine, Magna Graecia University, 88100, Catanzaro, Italy.
| | - Marcello Maggiolini
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036, Cosenza, Rende, Italy.
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Medina-Carmona E, Rizzuti B, Martín-Escolano R, Pacheco-García JL, Mesa-Torres N, Neira JL, Guzzi R, Pey AL. Phosphorylation compromises FAD binding and intracellular stability of wild-type and cancer-associated NQO1: Insights into flavo-proteome stability. Int J Biol Macromol 2018; 125:1275-1288. [PMID: 30243998 DOI: 10.1016/j.ijbiomac.2018.09.108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/30/2018] [Accepted: 09/18/2018] [Indexed: 02/07/2023]
Abstract
Over a quarter million of protein phosphorylation sites have been identified so far, although the effects of site-specific phosphorylation on protein function and stability, as well as their possible impact in the phenotypic manifestation in genetic diseases are vastly unknown. We investigated here the effects of phosphorylating S82 in human NADP(H):quinone oxidoreductase 1, a representative example of disease-associated flavoprotein in which protein stability is coupled to the intracellular flavin levels. Additionally, the cancer-associated P187S polymorphism causes inactivation and destabilization of the enzyme. By using extensive in vitro and in silico characterization of phosphomimetic S82D mutations, we showed that S82D locally affected the flavin binding site of the wild-type (WT) and P187S proteins thus altering flavin binding affinity, conformational stability and aggregation propensity. Consequently, the phosphomimetic S82D may destabilize the WT protein intracellularly by promoting the formation of the degradation-prone apo-protein. Noteworthy, WT and P187S proteins respond differently to the phosphomimetic mutation in terms of intracellular stability, further supporting differences in molecular recognition of these two variants by the proteasomal degradation pathway. We propose that phosphorylation could have critical consequences on stability and function of human flavoproteins, important for our understanding of genotype-phenotype relationships in their related genetic diseases.
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Affiliation(s)
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Rubén Martín-Escolano
- Department of Parasitology, Instituto de Investigación Biosanitaria (ibs.Granada), Hospitales Universitarios De Granada/University of Granada, 18071 Granada, Spain
| | | | - Noel Mesa-Torres
- Department of Physical Chemistry, University of Granada, 18071 Granada, Spain
| | - José L Neira
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche, Alicante, Spain; Instituto de Biocomputación y Física de los Sistemas Complejos (BIFI), 50009 Zaragoza, Spain
| | - Rita Guzzi
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy; Molecular Biophysics Laboratory, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Angel L Pey
- Department of Physical Chemistry, University of Granada, 18071 Granada, Spain.
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Grande F, Rizzuti B, Occhiuzzi MA, Ioele G, Casacchia T, Gelmini F, Guzzi R, Garofalo A, Statti G. Identification by Molecular Docking ofHomoisoflavones from Leopoldia comosa as Ligands of Estrogen Receptors. Molecules 2018; 23:molecules23040894. [PMID: 29649162 PMCID: PMC6017050 DOI: 10.3390/molecules23040894] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 02/07/2023] Open
Abstract
The physiological responses to estrogen hormones are mediated within specific tissues by at least two distinct receptors, ERα and ERβ. Several natural and synthetic molecules show activity by interacting with these proteins. In particular, a number of vegetal compounds known as phytoestrogens shows estrogenic or anti-estrogenic activity. The majority of these compounds belongs to the isoflavones family and the most representative one, genistein, shows anti-proliferative effects on various hormone-sensitive cancer cells, including breast, ovarian and prostate cancer. In this work we describe the identification of structurally related homoisoflavones isolated from Leopoldia comosa (L.) Parl. (L. comosa), a perennial bulbous plant, potentially useful as hormonal substitutes or complements in cancer treatments. Two of these compounds have been selected as potential ligands of estrogen receptors (ERs) and the interaction with both isoforms of estrogen receptors have been investigated through molecular docking on their crystallographic structures. The results provide evidence of the binding of these compounds to the target receptors and their interactions with key residues of the active sites of the two proteins, and thus they could represent suitable leads for the development of novel tools for the dissection of ER signaling and the development of new pharmacological treatments in hormone-sensitive cancers.
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Affiliation(s)
- Fedora Grande
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Ampl. Polifunzionale, Via P. Bucci, 87036 Rende (CS), Italy.
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Via P. Bucci, 87036 Rende (CS), Italy.
| | - Maria A Occhiuzzi
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Ampl. Polifunzionale, Via P. Bucci, 87036 Rende (CS), Italy.
| | - Giuseppina Ioele
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Ampl. Polifunzionale, Via P. Bucci, 87036 Rende (CS), Italy.
| | - Teresa Casacchia
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Ampl. Polifunzionale, Via P. Bucci, 87036 Rende (CS), Italy.
| | - Fabrizio Gelmini
- Department of Environmental Science and Policy-ESP, University of Milan, Via Celoria 2, 20133 Milan, Italy.
| | - Rita Guzzi
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Via P. Bucci, 87036 Rende (CS), Italy.
- Department of Physics, University of Calabria, Via P. Bucci, 87036 Rende (CS), Italy.
| | - Antonio Garofalo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Ampl. Polifunzionale, Via P. Bucci, 87036 Rende (CS), Italy.
| | - Giancarlo Statti
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Ampl. Polifunzionale, Via P. Bucci, 87036 Rende (CS), Italy.
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Evoli S, Mobley DL, Guzzi R, Rizzuti B. Multiple binding modes of ibuprofen in human serum albumin identified by absolute binding free energy calculations. Phys Chem Chem Phys 2018; 18:32358-32368. [PMID: 27854368 DOI: 10.1039/c6cp05680f] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Human serum albumin possesses multiple binding sites and transports a wide range of ligands that include the anti-inflammatory drug ibuprofen. A complete map of the binding sites of ibuprofen in albumin is difficult to obtain in traditional experiments, because of the structural adaptability of this protein in accommodating small ligands. In this work, we provide a set of predictions covering the geometry, affinity of binding and protonation state for the pharmaceutically most active form (S-isomer) of ibuprofen to albumin, by using absolute binding free energy calculations in combination with classical molecular dynamics (MD) simulations and molecular docking. The most favorable binding modes correctly reproduce several experimentally identified binding locations, which include the two Sudlow's drug sites (DS2 and DS1) and the fatty acid binding sites 6 and 2 (FA6 and FA2). Previously unknown details of the binding conformations were revealed for some of them, and formerly undetected binding modes were found in other protein sites. The calculated binding affinities exhibit trends which seem to agree with the available experimental data, and drastically degrade when the ligand is modeled in a protonated (neutral) state, indicating that ibuprofen associates with albumin preferentially in its charged form. These findings provide a detailed description of the binding of ibuprofen, help to explain a wide range of results reported in the literature in the last decades, and demonstrate the possibility of using simulation methods to predict ligand binding to albumin.
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Affiliation(s)
- Stefania Evoli
- Department of Physics, University of Calabria, 87036 Rende, Italy
| | - David L Mobley
- Departments of Pharmaceutical Sciences and Chemistry, University of California, Irvine, USA
| | - Rita Guzzi
- Department of Physics, University of Calabria, 87036 Rende, Italy and CNISM Unit, University of Calabria, 87036 Rende, Italy
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy.
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Guglielmelli A, Rizzuti B, Guzzi R. Stereoselective and domain-specific effects of ibuprofen on the thermal stability of human serum albumin. Eur J Pharm Sci 2017; 112:122-131. [PMID: 29158196 DOI: 10.1016/j.ejps.2017.11.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 10/31/2017] [Accepted: 11/16/2017] [Indexed: 12/20/2022]
Abstract
Ibuprofen is one of the most used anti-inflammatory drugs, and it is transported in the blood by human serum albumin, a major plasmatic protein with a peculiar adaptability in the binding of several different ligands. We have characterized the interaction between albumin and ibuprofen, either in racemic mixture, or in the S(+) and R(-) enantiomeric forms, by using differential scanning calorimetry, attenuated total reflectance Fourier transform infrared spectroscopy, and molecular dynamics simulation. The results show that increasing concentrations of ibuprofen (up to sixfold drug/protein molar ratio) improve the protein resistance to thermal unfolding without altering the secondary structure. Deconvolution of the calorimetric thermal profiles at different albumin/ibuprofen molar ratios demonstrates a selective stability of the protein domains where the binding sites of the drug are localized. At the highest ibuprofen concentration, the melting temperature increased by about 10°C with respect to the drug-free protein, whereas the unfolding enthalpy maintains an almost constant value. Furthermore, the degree of protein stabilization depends upon the chirality of the drug, and the R(-) enantiomer is more effective compared to the S(+) form. The stability is supported by molecular dynamics simulations, showing that ibuprofen maintains a stable coordination in the most favorable binding sites, leading to a more compact protein structure at high temperature. The overall results attest that the binding of ibuprofen determines on albumin a stereoselective and domain-specific stabilization with a predominantly entropic character, contributing to clarify significant aspects of the molecular mechanism of protein/drug interaction.
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Affiliation(s)
- Alexa Guglielmelli
- Molecular Biophysics Laboratory, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Rita Guzzi
- Molecular Biophysics Laboratory, Department of Physics, University of Calabria, 87036 Rende, Italy.
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Aloi E, Oranges M, Guzzi R, Bartucci R. Low-Temperature Dynamics of Chain-Labeled Lipids in Ester- and Ether-Linked Phosphatidylcholine Membranes. J Phys Chem B 2017; 121:9239-9246. [PMID: 28892381 DOI: 10.1021/acs.jpcb.7b07386] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Continuous wave electron paramagnetic resonance spectroscopy and two-pulse echo detected spectra of chain-labeled lipids are used to study the dynamics of frozen lipid membranes over the temperature range 77-260 K. Bilayers of ester-linked dihexadecanoylphosphatidylcholine (DPPC) with noninterdigitated chains and ether-linked dihexadecyl phosphatidylcholine (DHPC) with interdigitated chains are considered. Rapid stochastic librations of small angular amplitude are found in both lipid matrices. In noninterdigitated DPPC bilayers, the mean-square angular amplitude, [Formula: see text], of the motion increases with temperature and it is larger close to the chain termini than close to the polar/apolar interface. In contrast, in interdigitated DHPC lamellae, [Formula: see text] is small and temperature and label-position independent at low temperature and increases steeply at high temperature. The rotational correlation time, τc, of librations lies in the subnanosecond range for DPPC and in the nanosecond range for DHPC. In all membrane samples, the temperature dependence of [Formula: see text] resembles that of the mean-square atomic displacement revealed by neutron scattering and a dynamical transition is detected in the range 210-240 K. The results highlight the librational oscillations and the glass-like behavior in bilayer and interdigitated lipid membranes.
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Affiliation(s)
- Erika Aloi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria , 87036 Rende (CS), Italy
| | - Maria Oranges
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria , 87036 Rende (CS), Italy
| | - Rita Guzzi
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria , 87036 Rende (CS), Italy
| | - Rosa Bartucci
- Department of Physics, Molecular Biophysics Laboratory, University of Calabria , 87036 Rende (CS), Italy
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Patil NJ, Rishikesan S, Nikogeorgos N, Guzzi R, Lee S, Zappone B. Complexation and synergistic boundary lubrication of porcine gastric mucin and branched poly(ethyleneimine) in neutral aqueous solution. Soft Matter 2017; 13:590-599. [PMID: 27976775 DOI: 10.1039/c6sm01801g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Lubrication of soft polydimethylsiloxane (PDMS) elastomer interfaces was studied in aqueous mixtures of porcine gastric mucin (PGM) and branched polyethyleneimine (b-PEI) at neutral pH and various ionic strengths (0.1-1.0 M). While neither PGM nor b-PEI improved lubrication compared to polymer-free buffer solution, their mixtures produced a synergistic lubricating effect by reducing friction coefficients by nearly two orders of magnitude, especially at slow sliding speed in the boundary lubrication regime. An array of spectroscopic studies revealed that small cationic b-PEI molecules were able to strongly bind and penetrate into large anionic PGM molecules, producing an overall contraction of the randomly coiled PGM conformation. The interaction also affected the structure of the folded PGM protein terminals, decreased the surface potential and increased light absorbance in PGM:b-PEI mixtures. Adding an electrolyte (NaCl) weakened the aggregation between PGM and b-PEI, and degraded the lubrication synergy, indicating that electrostatic interactions drive PGM:b-PEI complexation.
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Affiliation(s)
- Navinkumar J Patil
- Dipartimento di Fisica, Università della Calabria, Cubo 31/C, Rende, CS 87036, Italy
| | | | - Nikolaos Nikogeorgos
- Department of Mechanical Engineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
| | - Rita Guzzi
- Dipartimento di Fisica, Università della Calabria, Cubo 31/C, Rende, CS 87036, Italy
| | - Seunghwan Lee
- Department of Mechanical Engineering, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
| | - Bruno Zappone
- Consiglio Nazionale delle Ricerche - Istituto di Nanotecnologia (CNR-Nanotec), SS Cosenza - LICRYL, c/o Dipartimento di Fisica, Università della Calabria, Cubo 33/B, Rende, CS 87036, Italy.
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Longo E, Ciuchi F, Guzzi R, Rizzuti B, Bartucci R. Resveratrol induces chain interdigitation in DPPC cell membrane model systems. Colloids Surf B Biointerfaces 2016; 148:615-621. [DOI: 10.1016/j.colsurfb.2016.09.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 09/23/2016] [Accepted: 09/26/2016] [Indexed: 12/26/2022]
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Stirpe A, Pantusa M, Rizzuti B, De Santo MP, Sportelli L, Bartucci R, Guzzi R. Resveratrol induces thermal stabilization of human serum albumin and modulates the early aggregation stage. Int J Biol Macromol 2016; 92:1049-1056. [DOI: 10.1016/j.ijbiomac.2016.08.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 08/03/2016] [Accepted: 08/06/2016] [Indexed: 10/21/2022]
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Guzzi R, Bartucci R. Electron spin resonance of spin-labeled lipid assemblies and proteins. Arch Biochem Biophys 2015; 580:102-11. [PMID: 26116378 DOI: 10.1016/j.abb.2015.06.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 06/18/2015] [Accepted: 06/22/2015] [Indexed: 01/29/2023]
Abstract
Spin-label electron spin resonance (ESR) spectroscopy is a valuable means to study molecular mobility and interactions in biological systems. This paper deals with conventional, continuous wave ESR of nitroxide spin-labels at 9-GHz providing an introduction to the basic principles of the technique and applications to self-assembled lipid aggregates and proteins. Emphasis is given to segmental lipid chain order and rotational dynamics of lipid structures, environmental polarity of membranes and proteins, structure and conformational dynamics of proteins.
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Affiliation(s)
- Rita Guzzi
- Department of Physics, University of Calabria, 87036 Rende (CS), Italy
| | - Rosa Bartucci
- Department of Physics, University of Calabria, 87036 Rende (CS), Italy.
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Guzzi R, Bartucci R, Esmann M, Marsh D. Lipid Librations at the Interface with the Na,K-ATPase. Biophys J 2015; 108:2825-32. [PMID: 26083922 DOI: 10.1016/j.bpj.2015.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/22/2015] [Accepted: 05/06/2015] [Indexed: 10/23/2022] Open
Abstract
Transitions between conformational substates of membrane proteins can be driven by torsional librations in the protein that may be coupled to librational fluctuations of the lipid chains. Here, librational motion of spin-labeled lipid chains in membranous Na,K-ATPase is investigated by spin-echo electron paramagnetic resonance. Lipids at the protein interface are targeted by using negatively charged spin-labeled fatty acids that display selectivity of interaction with the Na,K-ATPase. Echo-detected electron paramagnetic resonance spectra from native membranes are corrected for the contribution from the bilayer regions of the membrane by using spectra from dispersions of the extracted membrane lipids. Lipid librations at the protein interface have a flat profile with chain position, whereas librational fluctuations of the bilayer lipids increase pronouncedly from C-9 onward, then flatten off toward the terminal methyl end of the chains. This difference is accounted for by increased torsional amplitude at the chain ends in bilayers, while the amplitude remains restricted throughout the chain at the protein interface with a limited lengthening in correlation time. The temperature dependence of chain librations at the protein interface strongly resembles that of the spin-labeled protein side chains, suggesting solvent-mediated transitions in the protein are driven by fluctuations in the lipid environment.
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Affiliation(s)
- Rita Guzzi
- Department of Physics, Molecular Biophysics Laboratory and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Material Unit, University of Calabria, Ponte P. Bucci, Rende, Italy
| | - Rosa Bartucci
- Department of Physics, Molecular Biophysics Laboratory and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Material Unit, University of Calabria, Ponte P. Bucci, Rende, Italy
| | - Mikael Esmann
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Derek Marsh
- Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.
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Rizzuti B, Bartucci R, Sportelli L, Guzzi R. Fatty acid binding into the highest affinity site of human serum albumin observed in molecular dynamics simulation. Arch Biochem Biophys 2015; 579:18-25. [PMID: 26048999 DOI: 10.1016/j.abb.2015.05.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 11/24/2022]
Abstract
Multiple molecular dynamics simulations were performed to investigate the association of stearic acid into the highest affinity binding site of human serum albumin. All binding events ended with a rapid (<10 ps) lock-in of the fatty acid due to formation of a hydrogen bond with Tyr401. The kinetics and energetics of the penetration process both depended linearly on the positional shift of the fatty acid, with an average insertion time and free energy reduction of, respectively, 32 ± 20 ps and 0.70 ± 0.15 kcal/mol per methylene group absorbed. Binding events of longer duration (tbind>1 ns) were characterized by a slow exploration of the pocket entry and, frequently, of a nearby protein crevice corresponding to a metastable state along the route to the binding site. Taken all together, these findings reconstruct the following pathway for the binding process of stearic acid: (i) contact with the protein surface, possibly facilitated by the presence of an intermediate location, (ii) probing of the site entry, (iii) insertion into the protein, and (iv) lock-in at the final position. This general description may also apply to other long-chain fatty acids binding into any of the high-affinity sites of albumin, or to specific sites of other lipid-binding proteins.
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Affiliation(s)
- Bruno Rizzuti
- Licryl Laboratory, CNR-NANOTEC and CEMIF.Cal, University of Calabria, 87036 Rende, Italy.
| | - Rosa Bartucci
- Molecular Biophysics Laboratory and CNISM Unit, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Luigi Sportelli
- Molecular Biophysics Laboratory and CNISM Unit, Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Rita Guzzi
- Molecular Biophysics Laboratory and CNISM Unit, Department of Physics, University of Calabria, 87036 Rende, Italy
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Guzzi R, Rizzuti B, Labate C, Zappone B, De Santo MP. Ferric Ions Inhibit the Amyloid Fibrillation of β-Lactoglobulin at High Temperature. Biomacromolecules 2015; 16:1794-801. [PMID: 25989053 DOI: 10.1021/acs.biomac.5b00371] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The energetics of amyloid fibrillar aggregation of β-lactoglobulin (βLG) following incubation at high temperature and acid pH was studied by differential scanning calorimetry in the presence of Cu(2+) or Fe(3+) cations, and without any metal. Cu(2+) and metal-free protein solutions showed a distinct exothermic response that disappeared almost completely when the Fe(3+) molar concentration was ten times greater than the βLG concentration. Thioflavin T fluorescence studies in solution and atomic force microscopy analysis of the deposit left on flat mica substrates by heat-incubated βLG solutions correlated the absence of exothermic response of Fe(3+)-βLG solutions with a lack of fibril production. In contrast, abundant fibril deposits were observed for Cu(2+)-βLG solutions, with a rich polymorphism of multistrand fibrillar structures. Electron paramagnetic resonance revealed that Fe(3+) permanently binds to βLG in the aggregate state whereas Cu(2+) plays a catalytic role without binding to the protein. We propose that Fe(3+) inhibits fibril production after binding to a key region of the protein sequence, possibly interfering with the nucleation step of the fibrillation process and opening a nonfibrillar aggregation pathway. These findings suggest that transition metal ions can be utilized to effectively modulate protein self-assembly into a variety of structures with distinct morphologies at the nanoscale level.
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Affiliation(s)
- Rita Guzzi
- †Department of Physics, University of Calabria, Ponte P. Bucci 31C, 87036 Rende (CS), Italy.,‡CNISM Unit, University of Calabria, Ponte P. Bucci, Cubo 31C, 87036 Rende (CS), Italy
| | - Bruno Rizzuti
- §CNR-NANOTEC, LICRYL-UOS Cosenza and CEMIF.Cal, c/o Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Cristina Labate
- †Department of Physics, University of Calabria, Ponte P. Bucci 31C, 87036 Rende (CS), Italy
| | - Bruno Zappone
- §CNR-NANOTEC, LICRYL-UOS Cosenza and CEMIF.Cal, c/o Department of Physics, University of Calabria, 87036 Rende, Italy
| | - Maria P De Santo
- †Department of Physics, University of Calabria, Ponte P. Bucci 31C, 87036 Rende (CS), Italy
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Bartucci R, Guzzi R, Esmann M, Marsh D. Water penetration profile at the protein-lipid interface in Na,K-ATPase membranes. Biophys J 2015; 107:1375-82. [PMID: 25229145 DOI: 10.1016/j.bpj.2014.07.057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/05/2014] [Accepted: 07/30/2014] [Indexed: 11/28/2022] Open
Abstract
The affinity of ionized fatty acids for the Na,K-ATPase is used to determine the transmembrane profile of water penetration at the protein-lipid interface. The standardized intensity of the electron spin echo envelope modulation (ESEEM) from (2)H-hyperfine interaction with D2O is determined for stearic acid, n-SASL, spin-labeled systematically at the C-n atoms throughout the chain. In both native Na,K-ATPase membranes from shark salt gland and bilayers of the extracted membrane lipids, the D2O-ESEEM intensities of fully charged n-SASL decrease progressively with position down the fatty acid chain toward the terminal methyl group. Whereas the D2O intensities decrease sharply at the n = 9 position in the lipid bilayers, a much broader transition region in the range n = 6 to 10 is found with Na,K-ATPase membranes. Correction for the bilayer population in the membranes yields the intrinsic D2O-intensity profile at the protein-lipid interface. For positions at either end of the chains, the D2O concentrations at the protein interface are greater than in the lipid bilayer, and the positional profile is much broader. This reveals the higher polarity, and consequently higher intramembrane water concentration, at the protein-lipid interface. In particular, there is a significant water concentration adjacent to the protein at the membrane midplane, unlike the situation in the bilayer regions of this cholesterol-rich membrane. Experiments with protonated fatty acid and phosphatidylcholine spin labels, both of which have a considerably lower affinity for the Na,K-ATPase, confirm these results.
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Affiliation(s)
- Rosa Bartucci
- Department of Physics, Molecular Biophysics Laboratory and CNISM Unit, University of Calabria, Ponte P. Bucci, Cubo 31C, 87036 Rende (CS), Italy
| | - Rita Guzzi
- Department of Physics, Molecular Biophysics Laboratory and CNISM Unit, University of Calabria, Ponte P. Bucci, Cubo 31C, 87036 Rende (CS), Italy
| | - Mikael Esmann
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Derek Marsh
- Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany.
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Stirpe A, Pantusa M, Guzzi R, Bartucci R, Sportelli L. Chain interdigitation in DPPC bilayers induced by HgCl2: Evidences from continuous wave and pulsed EPR. Chem Phys Lipids 2014; 183:176-83. [DOI: 10.1016/j.chemphyslip.2014.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 07/08/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023]
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Evoli S, Guzzi R, Rizzuti B. Molecular simulations of β-lactoglobulin complexed with fatty acids reveal the structural basis of ligand affinity to internal and possible external binding sites. Proteins 2014; 82:2609-19. [DOI: 10.1002/prot.24625] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 05/29/2014] [Accepted: 06/05/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Stefania Evoli
- Department of Physics; University of Calabria; Ponte P. Bucci, Cubo 31C 87036 Rende (CS) Italy
- CNR-IPCF UOS of Cosenza, LiCryL and CEMIF.Cal; University of Calabria; Ponte P. Bucci, Cubo 33B 87036 Rende (CS) Italy
| | - Rita Guzzi
- Department of Physics; University of Calabria; Ponte P. Bucci, Cubo 31C 87036 Rende (CS) Italy
- CNISM Unit; University of Calabria; Ponte P. Bucci, Cubo 31C 87036 Rende (CS) Italy
| | - Bruno Rizzuti
- CNR-IPCF UOS of Cosenza, LiCryL and CEMIF.Cal; University of Calabria; Ponte P. Bucci, Cubo 33B 87036 Rende (CS) Italy
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Marsh D, Bartucci R, Guzzi R, Sportelli L, Esmann M. Librational fluctuations in protein glasses. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2013; 1834:1591-5. [DOI: 10.1016/j.bbapap.2013.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/25/2013] [Accepted: 05/03/2013] [Indexed: 10/26/2022]
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Guzzi R, Rizzuti B, Bartucci R. Dynamics and binding affinity of spin-labeled stearic acids in β-lactoglobulin: evidences from EPR spectroscopy and molecular dynamics simulation. J Phys Chem B 2012; 116:11608-15. [PMID: 22950964 DOI: 10.1021/jp3074392] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
β-Lactoglobulin (β-LG) is a member of the lipocalin protein family involved in the transport of fatty acids and other small hydrophobic molecules. The main binding site is at a central cavity, referred to as "calyx", formed by the protein β-barrel sandwich. Continuous-wave and pulsed Fourier transform electron spin resonance (cw- and FT-EPR) spectroscopy and molecular dynamics (MD) simulation were combined to investigate the interaction of fatty acids with bovine β-LG. Stearic acid bearing the nitroxide label at different positions, n, along the acyl chain (n-SASL, n = 5, 7, 10, 12, 16) were used. The EPR data show that the protein affinity for SASL decreases on going from n = 5 to 16. This behavior is due to the accommodation of the SASL in the protein calyx, which is hampered by steric hindrance of the doxyl ring for n ≥ 10, as evidenced by MD data. Conformation and dynamics of 5-SASL are similar to those of the unlabeled stearate molecule. 5-SASL in the protein binding site undergoes librational motion of small amplitude on the nanosecond time scale at cryogenic temperature and rotational dynamics with correlation time of 4.2 ns at physiological temperature. The results highlight the dynamical features of fatty acids/β-LG interaction.
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Affiliation(s)
- Rita Guzzi
- Department of Physics, University of Calabria, Ponte P. Bucci 31C, 87036 Rende (CS), Italy.
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Guzzi R, Sportelli L, Yanagisawa S, Li C, Kostrz D, Dennison C. The influence of active site loop mutations on the thermal stability of azurin from Pseudomonas aeruginosa. Arch Biochem Biophys 2012; 521:18-23. [PMID: 22446157 DOI: 10.1016/j.abb.2012.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 03/05/2012] [Accepted: 03/06/2012] [Indexed: 10/28/2022]
Abstract
The copper site and overall structures of azurin (AZ) variants in which the amicyanin (AMI) and plastocyanin (PC) metal binding loops have been introduced, AZAMI and AZPC, respectively, are similar to that of AZ, whereas the loop conformations resemble those in the native proteins. To assess the influence of these loop mutations on stability, the thermal unfolding of AZAMI and AZPC has been investigated by differential scanning calorimetry, absorption and fluorescence spectroscopy. The calorimetric profiles of both variants exhibit a complex shape consisting of two endothermic peaks and an exothermic peak. The temperature of the maximum heat of absorption for the single endothermic peak is 82.7°C for AZ, whereas for AZAMI and AZPC the most intense endothermic peaks are at 74.9 and 68.1°C comparable to values for AMI and PC, respectively. Denaturation investigated using the temperature dependence of the absorbance at ∼600nm and Trp emission, also demonstrates decreased stability for both loop mutants. The thermal transition between the native and the denaturated states is irreversible, scan rate dependent and consistent with the two-state irreversible model. The structure of the active-site loop has a dramatic effect on the kinetic stability and the unfolding pathway of cupredoxins.
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Affiliation(s)
- Rita Guzzi
- Molecular Biophysics Laboratory and CNISM Unit, Department of Physics, University of Calabria, Ponte P. Bucci, Cubo 31C, 87036 Rende (CS), Italy.
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Guzzi R, Babavali M, Bartucci R, Sportelli L, Esmann M, Marsh D. Spin-echo EPR of Na,K-ATPase unfolding by urea. Biochimica et Biophysica Acta (BBA) - Biomembranes 2011; 1808:1618-28. [DOI: 10.1016/j.bbamem.2010.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 11/03/2010] [Accepted: 11/03/2010] [Indexed: 11/15/2022]
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Rizzuti B, Zappone B, De Santo MP, Guzzi R. Native beta-lactoglobulin self-assembles into a hexagonal columnar phase on a solid surface. Langmuir 2010; 26:1090-1095. [PMID: 19877696 DOI: 10.1021/la902464f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Using electron scanning microscopy, we have studied the protein deposit left on silicon and mica substrates by dried droplets of aqueous solutions of bovine beta-lactoglobulin at low concentration and pH = 2-7. We have observed different self-assembled structures: homogeneous layers, hexagonal platelets and flower-shaped patterns laying flat on the surface, and rods formed by columns. Homogeneous layers covered the largest area of the droplet deposit. The other structures were found in small isolated regions, where the protein solution dried in the form of microdroplets. The presence of hexagonal platelets, flower-shaped patterns and columnar rods shows that beta-lactoglobulin self-assembles at the surface in a hexagonal columnar phase, which has never been observed in solution. A comparison with proteins showing similar aggregates suggests that beta-lactoglobulin structures grow from hexagonal germs composed of discotic nanometric building blocks, possibly possessing an octameric structure. We propose that discotic building blocks of beta-lactoglobulin may be produced by the anisotropic interaction with the solid surface.
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Affiliation(s)
- Bruno Rizzuti
- Licryl CNR-INFM and Cemif.Cal, University of Calabria, Ponte P. Bucci, Cubo 31C, 87036 Rende (CS), Italy
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Guzzi R, Bartucci R, Sportelli L, Esmann M, Marsh D. Conformational Heterogeneity and Spin-Labeled −SH Groups: Pulsed EPR of Na,K-ATPase. Biochemistry 2009; 48:8343-54. [DOI: 10.1021/bi900849z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. Guzzi
- Dipartimento di Fisica and UdR CNISM, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy
| | - R. Bartucci
- Dipartimento di Fisica and UdR CNISM, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy
| | - L. Sportelli
- Dipartimento di Fisica and UdR CNISM, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy
| | - M. Esmann
- Department of Physiology and Biophysics, Aarhus University, Aarhus, Denmark
| | - D. Marsh
- Max-Planck-Institut für biophysikalische Chemie, Abt. Spektroskopie, 37077 Göttingen, Germany
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Bartucci R, Guzzi R, Sportelli L, Marsh D. Intramembrane water associated with TOAC spin-labeled alamethicin: electron spin-echo envelope modulation by D2O. Biophys J 2009; 96:997-1007. [PMID: 19186137 DOI: 10.1016/j.bpj.2008.10.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 10/21/2008] [Indexed: 11/30/2022] Open
Abstract
Alamethicin is a 20-residue, hydrophobic, helical peptide, which forms voltage-sensitive ion channels in lipid membranes. The helicogenic, nitroxyl amino acid TOAC was substituted isosterically for Aib at residue positions 1, 8, or 16 in a F50/5 alamethicin analog to enable EPR studies. Electron spin-echo envelope modulation (ESEEM) spectroscopy was used to investigate the water exposure of TOAC-alamethicin introduced into membranes of saturated or unsaturated diacyl phosphatidylcholines that were dispersed in D2O. Echo-detected EPR spectra were used to assess the degree of assembly of the peptide in the membrane, via the instantaneous diffusion from intermolecular spin-spin interactions. The profile of residue exposure to water differs between membranes of saturated and unsaturated lipids. In monounsaturated dioleoyl phosphatidylcholine, D2O-ESEEM intensities decrease from TOAC(1) to TOAC(8) and TOAC(16) but not uniformly. This is consistent with a transmembrane orientation for the protoassembled state, in which TOAC(16) is located in the bilayer leaflet opposite to that of TOAC(1) and TOAC(8). Relative to the monomer in fluid bilayers, assembled alamethicin is disposed asymmetrically about the bilayer midplane. In saturated dimyristoyl phosphatidylcholine, the D2O-ESEEM intensity is greatest for TOAC(8), indicating a more superficial location for alamethicin, which correlates with the difference in orientation between gel- and fluid-phase membranes found by conventional EPR of TOAC-alamethicin in aligned phosphatidylcholine bilayers. Increasing alamethicin/lipid ratio in saturated phosphatidylcholine shifts the profile of water exposure toward that with unsaturated lipid, consistent with proposals of a critical concentration for switching between the two different membrane-associated states.
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Affiliation(s)
- R Bartucci
- Dipartimento di Fisica and Unità di Recerca Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia, Università della Calabria, Arcavacata di Rende, Italy
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Abstract
Molecular dynamics simulation has been carried out for the blue copper protein amicyanin from two different sources, Paracoccus denitrificans and Paraccocus versutus, to investigate the structural and dynamical properties common to the two molecules and to identify prominent features shared with proteins of the same family, the monomeric cupredoxins. The two amicyanins have almost identical secondary and tertiary structure. In the simulation, they differ for the number of hydrogen bonds in the main chain and the conformation of some beta-strands. However, they strictly maintain the arrangement of the portions of the beta-barrel that are conserved in the folding architecture of the blue copper proteins. Paracoccus versutus amicyanin equilibrates more rapidly, shows lower atomic deviation values, and is less rigid with respect to Paracoccus denitrificans amicyanin. Principal component analysis reveals that the conformational subspaces corresponding to eigenvectors with the same index for each of the two molecules are not necessarily equivalent. Nevertheless, a core scaffold with constrained dynamics exist for both amicyanins. In addition, two fairly flexible regions that are located on the opposite side with respect to the interaction sites with the partner molecules in the redox process have been evidenced in the protein structure. This description of amicyanin, with a few mobile regions remote from the active site and a rigid scaffold including most of the protein beta-barrel, has a close similarity with that of azurin and plastocyanin, two other cupredoxins previously investigated in simulation. Furthermore, similarities in the distribution of the atomic fluctuations indicate that amicyanin, azurin, and plastocyanin possess common dynamical features, in spite of differences in their structure. On the basis of these findings, we suggest that topological constraints imposed by the folding in correspondence of protein regions that are the most conserved determine the protein dynamics of the cupredoxin family. The dynamical properties of the cupredoxins might be controlled for functional advantages that include the binding mechanism with the biological partners and the collective inner motions of the protein matrix required for the electron transfer, whereas long-range conformational changes in the redox reaction should be excluded.
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Affiliation(s)
- Bruno Rizzuti
- Laboratorio Licryl CNR-INFM, Dipartimento di Fisica, Università della Calabria, Rende, Italy
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Guzzi R, Sportelli L, Sato K, Cannistraro S, Dennison C. Thermal unfolding studies of a phytocyanin. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2008; 1784:1997-2003. [DOI: 10.1016/j.bbapap.2008.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 07/03/2008] [Accepted: 07/03/2008] [Indexed: 10/21/2022]
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Manetto GD, Grasso DM, Milardi D, Pappalardo M, Guzzi R, Sportelli L, Verbeet MP, Canters GW, La Rosa C. The role played by the alpha-helix in the unfolding pathway and stability of azurin: switching between hierarchic and nonhierarchic folding. Chembiochem 2008; 8:1941-9. [PMID: 17868155 DOI: 10.1002/cbic.200700214] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The role played by the alpha-helix in determining the structure, the stability and the unfolding mechanism of azurin was addressed by studying a helix-depleted azurin variant produced by site-directed mutagenesis. The protein structure was investigated by CD, 1D (1)H NMR, fluorescence spectroscopy measurements and MD simulations, whilst EPR, UV-visible and cyclic voltammetry experiments were carried out to investigate the geometry and the properties of the Cu(II) site. The effects of the alpha-helix depletion on the thermal stability and the unfolding pathway of the protein were determined by DSC, UV/visible and fluorescence measurements at increasing temperature. The results show that, in the absence of the alpha-helix segment, the overall protein structure is maintained, and that only the Cu site is slightly modified. In contrast, the protein stability is diminished by about 60% with respect to the wild-type azurin. Moreover, the unfolding pathway of the mutant azurin involves the presence of detectable intermediates. In comparison with previous studies concerning other small beta-sheet cupredoxins, the results as a whole support the hypothesis that the presence of the alpha-helix can switch the folding of azurin from a hierarchic to a nonhierarchic mechanism in which the highly conserved beta-sheet core provides a scaffold for cooperative folding of the wild-type protein.
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Affiliation(s)
- Gaetano D Manetto
- Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, 95125 (CT), Italy
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Guzzi R, Arcangeli C, Bizzarri AR. A molecular dynamics simulation study of the solvent isotope effect on copper plastocyanin. Biophys Chem 2007; 82:9-22. [PMID: 17030337 DOI: 10.1016/s0301-4622(99)00097-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/1999] [Revised: 07/29/1999] [Accepted: 07/29/1999] [Indexed: 11/24/2022]
Abstract
The effect of heavy water on the structure and dynamics of copper plastocyanin as well as on some aspects of the solvent dynamics at the protein-solvent interfacial region have been investigated by molecular dynamics simulation. The simulated system has been analyzed in terms of the atomic root mean square deviation and fluctuations, intraprotein H-bond pattern, dynamical cross-correlation map and the results have been compared with those previously obtained for plastocyanin in H2O (Ciocchetti et al. Biophys. Chem. 69 (1997), 185-198). The simulated plastocyanin structure in the two solvents, averaging 1 ns, is very similar along the beta-structure regions, while the most significant differences are registered, analogous to the turns and the regions likely involved in the electron transfer pathway. Moreover, plastocyanin in D2O shows an increase in the number of both the intraprotein H-bonds and the residues involved in correlated motions. An analysis of the protein-solvent coupling evidenced that D2O makes the H-bond formation more difficult with the solvent molecules for positively charged and polar residues, while an opposite trend is observed for negatively charged residues. On the other hand, the frequency of exchange of the solvent molecules involved in the protein-solvent H-bond formation is significantly depressed in D2O. The results are discussed also in connection with protein functionality and briefly with some experimental results connected with the thermostability of proteins in D2O.
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Affiliation(s)
- R Guzzi
- Unita' INFM, Dipartimento di Fisica, Universita' della Calabria, I-87030 Rende, Italy.
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De Simone F, Guzzi R, Sportelli L, Marsh D, Bartucci R. Electron spin-echo studies of spin-labelled lipid membranes and free fatty acids interacting with human serum albumin. Biochimica et Biophysica Acta (BBA) - Biomembranes 2007; 1768:1541-9. [PMID: 17397796 DOI: 10.1016/j.bbamem.2007.02.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 01/29/2007] [Accepted: 02/12/2007] [Indexed: 11/23/2022]
Abstract
Human serum albumin (HSA) is an abundant plasma protein that transports fatty acids and also binds a wide variety of hydrophobic pharmacores. Echo-detected (ED) EPR spectra and D(2)O-electron spin echo envelope modulation (ESEEM) Fourier-transform spectra of spin-labelled free fatty acids and phospholipids were used jointly to investigate the binding of stearic acid to HSA and the adsorption of the protein on dipalmitoyl phosphatidylcholine (DPPC) membranes. In membranes, torsional librations are detected in the ED-spectra, the intensity of which depends on chain position at low temperature. Water penetration into the membrane is seen in the D(2)O-ESEEM spectra, the intensity of which decreases greatly at the middle of the membrane. Both the chain librational motion and the water penetration are only little affected by adsorption of serum albumin at the DPPC membrane surface. In contrast, both the librational motion and the accessibility of the chains to water are very different in the hydrophobic fatty acid binding sites of HSA from those in membranes. Indeed, the librational motion of bound fatty acids is suppressed at low temperature, and is similar for the different chain positions, at all temperatures. Correspondingly, all segments of the bound chains are accessible to water, to rather similar extents.
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Affiliation(s)
- Francesco De Simone
- Dipartimento di Fisica, Laboratorio di Biofisica Molecolare and UdR CNISM, Università della Calabria, I-87036 Arcavacata di Rende, CS, Italy
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Stirpe A, Sportelli L, Wijma H, Verbeet MP, Guzzi R. Thermal stability effects of removing the type-2 copper ligand His306 at the interface of nitrite reductase subunits. Eur Biophys J 2007; 36:805-13. [PMID: 17701241 DOI: 10.1007/s00249-007-0151-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 02/22/2007] [Accepted: 02/26/2007] [Indexed: 11/30/2022]
Abstract
Nitrite reductase (NiR) is a highly stable trimeric protein, which denatures via an intermediate, N(3)<--(k)-->U(3)--(k)-->F (N-native, U-unfolded and F-final). To understand the role of interfacial residues on protein stability, a type-2 copper site ligand, His306, has been mutated to an alanine. The characterization of the native state of the mutated protein highlights that this mutation prevents copper ions from binding to the type-2 site and eliminates catalytic activity. No significant alteration of the geometry of the type-1 site is observed. Study of the thermal denaturation of this His306Ala NiR variant by differential scanning calorimetry shows an endothermic irreversible profile, with maximum heat absorption at T (max) approximately equal to 85 degrees C, i.e., 15 degrees C lower than the corresponding value found for wild-type protein. The reduction of the protein thermal stability induced by the His306Ala replacement was also shown by optical spectroscopy. The denaturation pathway of the variant is compatible with the kinetic model N(3)--(k)-->F(3), where the protein irreversibly passes from the native to the final state. No evidence of subunits' dissociation has been found within the unfolding process. The results show that the type-2 copper sites, situated at the interface of two monomers, significantly contribute to both the stability and the denaturation mechanism of NiR.
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Affiliation(s)
- Andrea Stirpe
- Dipartimento di Fisica e Unità CNISM, Università della Calabria, Ponte P. Bucci, Cubo 31C, 87036 Arcavacata di Rende, Cosenza, Italy
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Rizzuti B, Sportelli L, Guzzi R. Structural, dynamical and functional aspects of the inner motions in the blue copper protein azurin. Biophys Chem 2007; 125:532-9. [PMID: 17157977 DOI: 10.1016/j.bpc.2006.11.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Revised: 11/15/2006] [Accepted: 11/16/2006] [Indexed: 11/28/2022]
Abstract
Molecular dynamics was applied to dissect out the internal motions of azurin, a copper protein performing electron transfer. Simulations of 16.5 ns were analyzed in search of coordinated displacements of amino acid residues that are important for the protein function. A region with high conformational instability was found in the 'southern' end of the molecule, far away from the copper site and the binding sites for the redox partners of azurin. By excluding the 'southern' region from the subsequent analysis, correlated motions were identified in the hydrophobic patch that surrounds the protein active site. The simulation results are in excellent agreement with recent NMR data on azurin in solution [A. V. Zhuravleva, D. M. Korzhnev, E. Kupce, A. S. Arseniev, M. Billeter, V. Y. Orekhov, Gated electron transfers and electron pathways in azurin: a NMR dynamic study at multiple fields and temperatures, J. Mol. Biol. 342 (2004) 1599-1611] and suggest a rationale for cooperative displacements of protein residues that are thought to be critical for the electron transfer process. A number of other structural and dynamic features of azurin are discussed in the context of the blue copper protein family and an explanation is proposed to account for the variability/conservation of some regions in the cupredoxins.
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Affiliation(s)
- Bruno Rizzuti
- Laboratorio Licryl CNR-INFM, Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, 87036 Rende, Italy
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Abstract
The contribution of the copper ion to the stability and to the unfolding pathway of pseudoazurin was investigated by a comparative analysis of the thermal unfolding of the Cu(II)-holo and apo form of the protein. The unfolding has been followed by calorimetry, fluorescence, optical density, and electron paramagnetic resonance (EPR) spectroscopy. The thermal transition of Cu(II)-holo pseudoazurin is irreversible and occurs between 60.0 and 67.3 degrees C, depending on the scan rate and technique used. The denaturation pathway of Cu(II)-holo pseudoazurin can be described by the Lumry-Eyring model: N --> U --> [corrected] F; the protein reversibly goes from the native (N) to the unfolded (U) state, and then irreversibly to the final (F) state. The simulation of the experimental calorimetric profiles, according to this model, allowed us to determine the thermodynamic and kinetic parameters of the two steps. The DeltaG value calculated for the Cu(II)-holo pseudoazurin is 39.2 kJ.mol(-1) at 25 degrees C. The sequence of events in the denaturation process of Cu(II)-holo pseudoazurin emergence starts with the disruption of the copper site and the hydrophobic core destabilization followed by the global protein unfolding. According to the EPR findings, the native type-1 copper ion shows type-2 copper features after the denaturation. The removal of the copper ion (apo form) significantly reduces the stability of the protein as evidenced by a DeltaG value of 16.5 kJ.mol(-1) at 25 degrees C. Moreover, the apo Paz unfolding occurs at 41.8 degrees C and is compatible with a two-state reversible process N --> [corrected] U.
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Affiliation(s)
- Andrea Stirpe
- Dipartimento di Fisica e Unità CNISM, Laboratorio di Biofisica Molecolare, Università della Calabria, Ponte P. Bucci - Cubo 30C, I-87036, Arcavacata di Rende (CS), Italy
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Bentini GG, Bianconi M, Cerutti A, Nubile A, Cerabolini P, Chiarini M, Pennestrì G, Dinicolantonio W, Guzzi R. A New Miniaturised Optical System for Chemical Species Spectroscopic Detection Based on a Scanning Integrated Mach–Zehnder Microinterferometer on LiNbO3. ORIGINS LIFE EVOL B 2006; 36:597-603. [PMID: 17136430 DOI: 10.1007/s11084-006-9052-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Absorption or emission spectroscopy is a powerful tool for detecting chemical compounds, diluted in fluid media: the sensitivity of this technique depends on the optical path of the source radiation, on the spectral window used for analysis and on the spectrometer performances. In this view, we designed and produced the first prototypes of an integrated scanning Fourier Transform Microinterferometer with Mach-Zehnder geometry, by using MEOS (Micro Electro Optical Systems) technologies. The microdevice, obtained by fabricating integrated optical waveguides on LiNbO(3) (LN) crystals, is electrically driven, without moving parts, by exploiting the electrooptical properties of the material. The microdevice operates the Fourier Transform of the input radiation spectral distribution, which can be reconstructed starting from the output signal by means of Fast Fourier Transform (FFT) techniques. The microinterferometer weights few grams, the power consumption is of a few mW and, in principle, can operate in the LN transmittance range (0.36-4.5 microm). The microinterferometer performances were preliminary tested in the (0.4-1.7 microm) spectral window. In the Visible region (0.4-0.7 mum) this microsystem demonstrated a spectral resolution suitable for detecting the characteristic lines of the solar spectrum together with the absorption bands of common gases present in Earth's atmosphere. In a further experiment we tested its performances for gas trace detection by using a calibrated NO(2) optical gas cell, showing the possibility to reveal up to 10 ppb, when suitable optical paths are used. Finally, colorimetry tests for the titration of an organic dye (E131) in alcohol solution are presented.
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Affiliation(s)
- G G Bentini
- IMM-Section of Bologna--C.N.R., Italian National Research Council, via Gobetti 101, 40129 Bologna, Italy.
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Bartucci R, Erilov DA, Guzzi R, Sportelli L, Dzuba SA, Marsh D. Time-resolved electron spin resonance studies of spin-labelled lipids in membranes. Chem Phys Lipids 2006; 141:142-57. [PMID: 16564516 DOI: 10.1016/j.chemphyslip.2006.02.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Accepted: 02/20/2006] [Indexed: 11/22/2022]
Abstract
Recently, developments in time-resolved spin-label electron spin resonance (ESR) spectroscopy have contributed considerably to the study of biomembranes. Two different applications of electron spin echo spectroscopy of spin-labelled phospholipids are reviewed here: (1) the use of partially relaxed echo-detected ESR spectra to study the librational lipid-chain motions in the low-temperature phases of phospholipid bilayers; (2) the use of electron spin echo envelope modulation spectroscopy to determine the penetration of water into phospholipid membranes. Results are described for phosphatidylcholine bilayer membranes, with and without equimolar cholesterol, that are obtained with phosphatidylcholine spin probes site-specifically labelled throughout the sn-2 chain.
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Affiliation(s)
- Rosa Bartucci
- Dipartimento di Fisica, Università della Calabria, Arcavacata di Rende (CS), Italy.
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Stirpe A, Guzzi R, Wijma H, Verbeet MP, Canters GW, Sportelli L. Calorimetric and spectroscopic investigations of the thermal denaturation of wild type nitrite reductase. Biochim Biophys Acta 2005; 1752:47-55. [PMID: 16085470 DOI: 10.1016/j.bbapap.2005.07.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Revised: 07/12/2005] [Accepted: 07/12/2005] [Indexed: 11/25/2022]
Abstract
Nitrite reductase (NiR) is a multicopper protein, with a trimeric structure containing two types of copper site: type 1 is present in each subunit whereas type 2 is localized at the subunits interface. The paper reports on the thermal behaviour of wild type NiR from Alcaligenes faecalis S-6. The temperature-induced changes of the copper centres are characterized by optical spectroscopy and electron paramagnetic resonance spectroscopy, and by establishing the thermal stability by differential scanning calorimetry. The calorimetric profile of the enzyme shows a single endothermic peak with maximum heat absorption at T(m) approximately 100 degrees C, revealing an exceptional thermal stability. The thermal transition is irreversible and the scan rate dependence of the calorimetric trace indicates that the denaturation of NiR is kinetically controlled. The divergence of the activation energy values determined by different methods is used as a criterion for the inapplicability of the one-step irreversible model. The best fit of the DSC profiles is obtained when the classical Lumry-Eyring model, N<-->U-->F, is considered. The simulation results indicate that the irreversible step prevails on the reversible one. Moreover, it is found that the conformational changes within the type-1 copper environments precede the denaturation of the whole protein. No evidence of protein dissociation within the temperature range investigated was observed.
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Affiliation(s)
- Andrea Stirpe
- Dipartimento di Fisica e Unità INFM, Laboratorio di Biofisica Molecolare, Università della Calabria, Ponte P. Bucci-Cubo 31C, I-87036, Arcavacata di Rende (CS), Italy
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