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Famulari A, Correddu D, Di Nardo G, Gilardi G, Mitrikas G, Chiesa M, García-Rubio I. Heme Spin Distribution in the Substrate-Free and Inhibited Novel CYP116B5hd: A Multifrequency Hyperfine Sublevel Correlation (HYSCORE) Study. Molecules 2024; 29:518. [PMID: 38276601 PMCID: PMC10819608 DOI: 10.3390/molecules29020518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/29/2023] [Accepted: 01/16/2024] [Indexed: 01/27/2024] Open
Abstract
The cytochrome P450 family consists of ubiquitous monooxygenases with the potential to perform a wide variety of catalytic applications. Among the members of this family, CYP116B5hd shows a very prominent resistance to peracid damage, a property that makes it a promising tool for fine chemical synthesis using the peroxide shunt. In this meticulous study, we use hyperfine spectroscopy with a multifrequency approach (X- and Q-band) to characterize in detail the electronic structure of the heme iron of CYP116B5hd in the resting state, which provides structural details about its active site. The hyperfine dipole-dipole interaction between the electron and proton nuclear spins allows for the locating of two different protons from the coordinated water and a beta proton from the cysteine axial ligand of heme iron with respect to the magnetic axes centered on the iron. Additionally, since new anti-cancer therapies target the inhibition of P450s, here we use the CYP116B5hd system-imidazole as a model for studying cytochrome P450 inhibition by an azo compound. The effects of the inhibition of protein by imidazole in the active-site geometry and electron spin distribution are presented. The binding of imidazole to CYP116B5hd results in an imidazole-nitrogen axial coordination and a low-spin heme FeIII. HYSCORE experiments were used to detect the hyperfine interactions. The combined interpretation of the gyromagnetic tensor and the hyperfine and quadrupole tensors of magnetic nuclei coupled to the iron electron spin allowed us to obtain a precise picture of the active-site geometry, including the orientation of the semi-occupied orbitals and magnetic axes, which coincide with the porphyrin N-Fe-N axes. The electronic structure of the iron does not seem to be affected by imidazole binding. Two different possible coordination geometries of the axial imidazole were observed. The angles between gx (coinciding with one of the N-Fe-N axes) and the projection of the imidazole plane on the heme were determined to be -60° and -25° for each of the two possibilities via measurement of the hyperfine structure of the axially coordinated 14N.
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Affiliation(s)
- Antonino Famulari
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain;
- Department of Chemistry, University of Turin, Via Giuria 9, 10125 Torino, Italy;
| | - Danilo Correddu
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy (G.D.N.); (G.G.)
| | - Giovanna Di Nardo
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy (G.D.N.); (G.G.)
| | - Gianfranco Gilardi
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Torino, Italy (G.D.N.); (G.G.)
| | - George Mitrikas
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15341 Athens, Greece;
| | - Mario Chiesa
- Department of Chemistry, University of Turin, Via Giuria 9, 10125 Torino, Italy;
| | - Inés García-Rubio
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain;
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
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2
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EPR characterization of the heme domain of a self-sufficient cytochrome P450 (CYP116B5). J Inorg Biochem 2022; 231:111785. [DOI: 10.1016/j.jinorgbio.2022.111785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 02/25/2022] [Accepted: 02/26/2022] [Indexed: 11/19/2022]
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3
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Van Doorslaer S. Understanding heme proteins with hyperfine spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:79-88. [PMID: 28579104 DOI: 10.1016/j.jmr.2017.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 06/07/2023]
Abstract
Heme proteins are versatile proteins that are involved in a large number of biological processes. Many spectroscopic methods are used to gain insight into the different mechanistic processes governing heme-protein functions. Since many (intermediate) states of heme proteins are paramagnetic, electron paramagnetic resonance (EPR) methods, such as hyperfine spectroscopy, offer unique tools for these investigations. This perspective gives an overview of the use of state-of-the-art hyperfine spectroscopy in heme research, focusing on the advantages, limits and challenges of the different techniques.
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Affiliation(s)
- Sabine Van Doorslaer
- BIMEF Laboratory, Department of Physics, University of Antwerp, B-2610 Antwerp, Belgium.
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4
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Ascenzi P, di Masi A, Leboffe L, Fiocchetti M, Nuzzo MT, Brunori M, Marino M. Neuroglobin: From structure to function in health and disease. Mol Aspects Med 2016; 52:1-48. [DOI: 10.1016/j.mam.2016.10.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 10/27/2016] [Accepted: 10/27/2016] [Indexed: 01/01/2023]
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5
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Trashin S, de Jong M, Luyckx E, Dewilde S, De Wael K. Electrochemical Evidence for Neuroglobin Activity on NO at Physiological Concentrations. J Biol Chem 2016; 291:18959-66. [PMID: 27402851 DOI: 10.1074/jbc.m116.730176] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Indexed: 11/06/2022] Open
Abstract
The true function of neuroglobin (Ngb) and, particularly, human Ngb (NGB) has been under debate since its discovery 15 years ago. It has been expected to play a role in oxygen binding/supply, but a variety of other functions have been put forward, including NO dioxygenase activity. However, in vitro studies that could unravel these potential roles have been hampered by the lack of an Ngb-specific reductase. In this work, we used electrochemical measurements to investigate the role of an intermittent internal disulfide bridge in determining NO oxidation kinetics at physiological NO concentrations. The use of a polarized electrode to efficiently interconvert the ferric (Fe(3+)) and ferrous (Fe(2+)) forms of an immobilized NGB showed that the disulfide bridge both defines the kinetics of NO dioxygenase activity and regulates appearance of the free ferrous deoxy-NGB, which is the redox active form of the protein in contrast to oxy-NGB. Our studies further identified a role for the distal histidine, interacting with the hexacoordinated iron atom of the heme, in oxidation kinetics. These findings may be relevant in vivo, for example, in blocking apoptosis by reduction of ferric cytochrome c, and gentle tuning of NO concentration in the tissues.
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Affiliation(s)
| | | | - Evi Luyckx
- Biomedical Sciences, University of Antwerp, 2010 Antwerp, Belgium
| | - Sylvia Dewilde
- Biomedical Sciences, University of Antwerp, 2010 Antwerp, Belgium
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6
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Ezhevskaya M, Bordignon E, Polyhach Y, Moens L, Dewilde S, Jeschke G, Van Doorslaer S. Distance determination between low-spin ferric haem and nitroxide spin label using DEER: the neuroglobin case. Mol Phys 2013. [DOI: 10.1080/00268976.2013.813592] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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7
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An N-myristoylated globin with a redox-sensing function that regulates the defecation cycle in Caenorhabditis elegans. PLoS One 2012; 7:e48768. [PMID: 23251335 PMCID: PMC3520999 DOI: 10.1371/journal.pone.0048768] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 10/04/2012] [Indexed: 01/17/2023] Open
Abstract
Globins occur in all kingdoms of life where they fulfill a wide variety of functions. In the past they used to be primarily characterized as oxygen transport/storage proteins, but since the discovery of new members of the globin family like neuroglobin and cytoglobin, more diverse and complex functions have been assigned to this heterogeneous family. Here we propose a function for a membrane-bound globin of C. elegans, GLB-26. This globin was predicted to be myristoylated at its N-terminus, a post-translational modification only recently described in the globin family. In vivo, this globin is found in the membrane of the head mesodermal cell and in the tail stomato-intestinal and anal depressor muscle cells. Since GLB-26 is almost directly oxidized when exposed to oxygen, we postulate a possible function as electron transfer protein. Phenotypical studies show that GLB-26 takes part in regulating the length of the defecation cycle in C. elegans under oxidative stress conditions.
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8
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Rapatskiy L, Cox N, Savitsky A, Ames WM, Sander J, Nowaczyk MM, Rögner M, Boussac A, Neese F, Messinger J, Lubitz W. Detection of the Water-Binding Sites of the Oxygen-Evolving Complex of Photosystem II Using W-Band 17O Electron–Electron Double Resonance-Detected NMR Spectroscopy. J Am Chem Soc 2012; 134:16619-34. [DOI: 10.1021/ja3053267] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Leonid Rapatskiy
- Max-Planck-Institut für
Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Nicholas Cox
- Max-Planck-Institut für
Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Anton Savitsky
- Max-Planck-Institut für
Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - William M. Ames
- Max-Planck-Institut für
Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Julia Sander
- Plant
Biochemistry, Ruhr University Bochum, Universitätsstrasse
150, D-44780 Bochum, Germany
| | - Marc. M. Nowaczyk
- Plant
Biochemistry, Ruhr University Bochum, Universitätsstrasse
150, D-44780 Bochum, Germany
| | - Matthias Rögner
- Plant
Biochemistry, Ruhr University Bochum, Universitätsstrasse
150, D-44780 Bochum, Germany
| | - Alain Boussac
- iBiTec-S, URA UMR 8221, CEA Saclay,
91191 Gif-sur-Yvette, France
| | - Frank Neese
- Max-Planck-Institut für
Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
| | - Johannes Messinger
- Department of Chemistry, Chemical
Biological Centre (KBC), Umeå University, S-90187 Umeå, Sweden
| | - Wolfgang Lubitz
- Max-Planck-Institut für
Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim
an der Ruhr, Germany
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9
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Van Doorslaer S, Tilleman L, Verrept B, Desmet F, Maurelli S, Trandafir F, Moens L, Dewilde S. Marked difference in the electronic structure of cyanide-ligated ferric protoglobins and myoglobin due to heme ruffling. Inorg Chem 2012; 51:8834-41. [PMID: 22877248 DOI: 10.1021/ic3007074] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Electron paramagnetic resonance experiments reveal a significant difference between the principal g values (and hence ligand-field parameters) of the ferric cyanide-ligated form of different variants of the protoglobin of Methanosarcina acetivorans (MaPgb) and of horse heart myoglobin (hhMb). The largest principal g value of the ferric cyanide-ligated MaPgb variants is found to be significantly lower than for any of the other globins reported so far. This is at least partially caused by the strong heme distortions as proven by the determination of the hyperfine interaction of the heme nitrogens and mesoprotons. Furthermore, the experiments confirm recent theoretical predictions [Forti, F.; Boechi, L., Bikiel, D., Martí, M.A.; Nardini, M.; Bolognesi, M.; Viappiani, C.; Estrin, D.; Luque, F. J. J. Phys. Chem. B 2011, 115, 13771-13780] that Phe(G8)145 plays a crucial role in the ligand modulation in MaPgb. Finally, the influence of the N-terminal 20 amino-acid chain on the heme pocket in these protoglobins is also proven.
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10
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EPR investigation of the role of B10 phenylalanine in neuroglobin — Evidence that B10Phe mediates structural changes in the heme region upon disulfide-bridge formation. J Inorg Biochem 2011; 105:1131-7. [DOI: 10.1016/j.jinorgbio.2011.05.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 05/31/2011] [Accepted: 05/31/2011] [Indexed: 11/18/2022]
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11
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Maurelli S, Chiesa M, Giamello E, Di Nardo G, V. Ferrero VE, Gilardi G, Van Doorslaer S. Direct spectroscopic evidence for binding of anastrozole to the iron heme of human aromatase. Peering into the mechanism of aromatase inhibition. Chem Commun (Camb) 2011; 47:10737-9. [DOI: 10.1039/c1cc13872c] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Ioanitescu AI, Doorslaer SV, Dewilde S, Endeward B, Moens L. Probing the heme-pocket structure of the paramagnetic forms of cytoglobin and a distal histidine mutant using electron paramagnetic resonance. Mol Phys 2010. [DOI: 10.1080/00268970701616030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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13
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Structure and reactivity of hexacoordinate hemoglobins. Biophys Chem 2010; 152:1-14. [PMID: 20933319 DOI: 10.1016/j.bpc.2010.08.008] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/20/2010] [Accepted: 08/21/2010] [Indexed: 01/07/2023]
Abstract
The heme prosthetic group in hemoglobins is most often attached to the globin through coordination of either one or two histidine side chains. Those proteins with one histidine coordinating the heme iron are called "pentacoordinate" hemoglobins, a group represented by red blood cell hemoglobin and most other oxygen transporters. Those with two histidines are called "hexacoordinate hemoglobins", which have broad representation among eukaryotes. Coordination of the second histidine in hexacoordinate Hbs is reversible, allowing for binding of exogenous ligands like oxygen, carbon monoxide, and nitric oxide. Research over the past several years has produced a fairly detailed picture of the structure and biochemistry of hexacoordinate hemoglobins from several species including neuroglobin and cytoglobin in animals, and the nonsymbiotic hemoglobins in plants. However, a clear understanding of the physiological functions of these proteins remains an elusive goal.
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14
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Chuang PY, Conley YP, Poloyac SM, Okonkwo DO, Ren D, Sherwood PR, Hravnak M, Alexander SA. Neuroglobin genetic polymorphisms and their relationship to functional outcomes after traumatic brain injury. J Neurotrauma 2010; 27:999-1006. [PMID: 20345238 PMCID: PMC2943497 DOI: 10.1089/neu.2009.1129] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neuroglobin has shown rich neuroprotective effects against cerebral hypoxia, and therefore has the potential to impact outcomes after traumatic brain injury (TBI). However, to date an association between genetic variation within the human neuroglobin (NGB) gene and recovery post-TBI has not been reported. The purpose of this study was to explore the relationship between NGB genotypes and outcomes (as assessed by the Glasgow Outcome Scale [GOS], the Disability Rating Scale [DRS], and the Neurobehavioral Rating Scale-Revised [NRS-R]) after severe TBI. Genotyping using TaqMan allele discrimination for two tagging single nucleotide polymorphisms (tSNPs) that represent the two haplotype blocks for NGB (rs3783988 and rs10133981) was completed on DNA obtained from 196 Caucasian patients recovering from severe TBI. Patients were dichotomized based on the presence of the variant allele for each tSNP. Chi-square and Fisher's exact tests were used to compare characteristics between groups. Multivariate linear regression was used to examine NGB tSNPs and recovery from severe TBI. Subjects with the TT genotype (wild-type) for rs3783988 were more likely to have better GOS and DRS scores at 3, 6, 12, and 24 months, while rs10133981 genotype was not significantly related to functional outcome. After controlling for age, gender, and Glasgow Coma Scale (GCS) score, those subjects with the rs3783988 TT genotype had more than a 2.65-times greater likelihood of better functional outcomes than individuals with genotypes harboring a variant allele. Data suggest that the haplotype block represented by rs3783988 in NGB appears to influence recovery after severe TBI. Represented within this haplotype block of NGB is the region that codes for the oxygen-binding portion of NGB.
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Affiliation(s)
- Pei-Ying Chuang
- Acute/Tertiary Care Department, Health Promotion and Development, School of Nursing, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
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15
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Xu J, Li L, Yin G, Li H, Du W. Ligand orientation of human neuroglobin obtained from solution NMR and molecular dynamics simulation as compared with X-ray crystallography. J Inorg Biochem 2009; 103:1693-701. [PMID: 19850349 DOI: 10.1016/j.jinorgbio.2009.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 09/17/2009] [Accepted: 09/21/2009] [Indexed: 10/20/2022]
Abstract
Neuroglobin, a new member of hemoprotein family, can reversibly bind oxygen and take part in many biological processes such as enzymatic reaction, signal transduction and the mitochondria function. Different from myoglobin and hemoglobin, it has a hexacoordinated heme environment, with histidyl imidazole of proximal His(96)(F8) and distal His(64)(E7) directly bound to the metal ion. In the present work, solution (1)H NMR spectroscopy was employed to investigate the electronic structure of heme center of wild-type met-human neuroglobin. The resonances of heme protons and key residues in the heme pocket were assigned. Two heme orientations resulting from a 180 degrees rotation about the alpha-gamma-meso axis with a population ratio about 2:1 were observed. Then the (1)H NMR chemical shifts of the ferriheme methyl groups were used to predict orientations of the axial ligand. The obtained axial ligand plane angle phi is consistent with that from the molecular dynamics simulation but not with those from the crystal data. Compared with mouse neuroglobin, the obtained average ligand orientation of human neuroglobin reflects the changeability of heme environment for the Ngb family.
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Affiliation(s)
- Jia Xu
- Department of Chemistry, Renmin University of China, Beijing 100872, China
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16
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Ioanitescu AI, Van Doorslaer S, Dewilde S, Moens L. Unusual flexibility of distal and proximal histidine residues in the haem pocket of Drosophila melanogaster haemoglobin. Metallomics 2009; 1:256-64. [PMID: 21305121 DOI: 10.1039/b902059b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Several pH-dependent low-spin ferric haem forms are identified in a frozen solution of the ferric ¹²¹Cys→Ser mutant of Drosophila melanogaster haemoglobin (DmHb1*) using electron paramagnetic resonance (EPR) techniques. Different forms with EPR parameters typical of bis-histidine coordinated haem iron centers were observed. Strong pH-dependent changes in the EPR signatures were observed related to changes in the haem pocket. The pulsed EPR data indicate that both the distal and proximal histidine exhibit a large libration around the Fe-N(His) axis. The resonance Raman spectra of the CO-ligated ferrous form of Drosophila melanogaster haemoglobin are typical of an open conformation, with little stabilization of the CO ligand by the surrounding amino-acid residues. The EPR data of the cyanide-ligated ferric DmHb1* indicates a close similarity with cyanide-ligated ferric myoglobin. The structural characteristics of DmHb1* are found to clearly differ from those of other bis-histidine-coordinated globins.
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17
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García-Rubio I, Alonso PJ, Medina M, Martínez JI. Hyperfine correlation spectroscopy and electron spin echo envelope modulation spectroscopy study of the two coexisting forms of the hemeprotein cytochrome c6 from Anabaena Pcc7119. Biophys J 2009; 96:141-52. [PMID: 18835911 PMCID: PMC2710011 DOI: 10.1529/biophysj.108.133272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 09/04/2008] [Indexed: 11/18/2022] Open
Abstract
Oxidized cytochrome c(6) from Anabaena PCC 7119 was studied by electron spin echo envelope modulation spectroscopy. Hyperfine couplings of the unpaired electron with several nuclei were detected, in particular those of the nitrogens bound to the iron atom. Combining the experimental information here presented and previous continuous wave-electron paramagnetic resonance and electron nuclear double resonance results, some details on the electronic structure of the heme center in the protein are obtained. These results are discussed on the basis of a molecular model that considers one unpaired electron localized mainly in the iron d orbitals and propagation of the spin density within the heme center via spin polarization of the nitrogen sigma-orbitals. The coexistence of two heme forms at physiological pH values in this c-type cytochrome is also discussed taking into account the experimental evidence.
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Affiliation(s)
- Inés García-Rubio
- Instituto de Ciencia de Materiales de Aragón, Consejo Superior de Investigaciones Cientificas-Universidad de Zaragoza, Zaragoza, Spain
| | - Pablo J. Alonso
- Instituto de Ciencia de Materiales de Aragón, Consejo Superior de Investigaciones Cientificas-Universidad de Zaragoza, Zaragoza, Spain
| | - Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, and Institute of Biocomputation and Physics of Complex Systems, Universidad de Zaragoza, Zaragoza, Spain
| | - Jesús I. Martínez
- Instituto de Ciencia de Materiales de Aragón, Consejo Superior de Investigaciones Cientificas-Universidad de Zaragoza, Zaragoza, Spain
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18
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Advanced Pulse EPR Methods for the Characterization of Metalloproteins. HIGH RESOLUTION EPR 2009. [DOI: 10.1007/978-0-387-84856-3_2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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19
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Van Doorslaer S, Desmet F. The power of using continuous-wave and pulsed electron paramagnetic resonance methods for the structure analysis of ferric forms and nitric oxide-ligated ferrous forms of globins. Methods Enzymol 2008; 437:287-310. [PMID: 18433634 DOI: 10.1016/s0076-6879(07)37015-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Abstract
For several decades now, electron paramagnetic resonance (EPR) has been a valuable spectroscopic tool for the characterization of globin proteins. In the early years, the majority of EPR studies were performed using standard continuous-wave EPR techniques at conventional microwave frequencies. In the last years, the field of EPR has known tremendous technological developments, including the introduction of advanced pulsed EPR and high-frequency EPR techniques. After a short overview of the basics of EPR and recent advances in the field, we will illustrate how these different EPR methods can provide information about the dynamics and geometric and electronic structures of heme proteins. Although the main focus of this chapter lies on the EPR analysis of nitric oxide-ligated ferrous heme proteins and ferric heme systems, we also briefly outline the possibility of site-directed spin labeling of heme proteins. The last section highlights the future potential and challenges in using this magnetic resonance technique in globin research.
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Affiliation(s)
- Sabine Van Doorslaer
- University of Antwerp, Department of Physics, SIBAC Laboratory, Antwerp, Belgium
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20
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Fittipaldi M, García-Rubio I, Trandafir F, Gromov I, Schweiger A, Bouwen A, Van Doorslaer S. A multi-frequency pulse EPR and ENDOR approach to study strongly coupled nuclei in frozen solutions of high-spin ferric heme proteins. J Phys Chem B 2008; 112:3859-70. [PMID: 18321089 DOI: 10.1021/jp709854x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In spite of the tremendous progress in the field of pulse electron paramagnetic resonance (EPR) in recent years, these techniques have been scarcely used to investigate high-spin (HS) ferric heme proteins. Several technical and spin-system-specific reasons can be identified for this. Additional problems arise when no single crystals of the heme protein are available. In this work, we use the example of a frozen solution of aquometmyoglobin (metMb) to show how a multi-frequency pulse EPR approach can overcome these problems. In particular, the performance of the following pulse EPR techniques are tested: Davies electron nuclear double resonance (ENDOR), hyperfine correlated ENDOR (HYEND), electron-electron double resonance (ELDOR)-detected NMR, and several variants of hyperfine sublevel correlation (HYSCORE) spectroscopy including matched and SMART HYSCORE. The pulse EPR experiments are performed at X-, Q- and W-band microwave frequencies. The advantages and drawbacks of the different methods are discussed in relation to the nuclear interaction that they intend to reveal. The analysis of the spectra is supported by several simulation procedures, which are discussed. This work focuses on the analysis of the hyperfine and nuclear-quadrupole tensors of the strongly coupled nuclei of the first coordination sphere, namely, the directly coordinating heme and histidine nitrogens and the 17O nucleus of the distal water ligand. For the latter, 17O-isotope labeling was used. The accuracy of our results and the spectral resolution are compared in detail to an earlier single-crystal continuous-wave ENDOR study on metMb, and it will be shown how additional information can be obtained from the multi-frequency approach. The current work is therefore prone to become a template for future EPR/ENDOR investigations of HS ferric heme proteins for which no single crystals are available.
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Affiliation(s)
- M Fittipaldi
- Department of Physics, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk-Antwerp, Belgium
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21
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Van Doorslaer S, Vinck E. The strength of EPR and ENDOR techniques in revealing structure-function relationships in metalloproteins. Phys Chem Chem Phys 2007; 9:4620-38. [PMID: 17700864 DOI: 10.1039/b701568b] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent technological and methodological advances have strongly increased the potential of electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) techniques to characterize the structure and dynamics of metalloproteins. These developments include the introduction of powerful pulsed EPR/ENDOR methodologies and the development of spectrometers operating at very high microwave frequencies and high magnetic fields. This overview focuses on how valuable information about metalloprotein structure-function relations can be obtained using a combination of EPR and ENDOR techniques. After an overview of the historical development and a limited theoretical description of some of the key EPR and ENDOR techniques, their potential will be highlighted using selected examples of applications to iron-, nickel-, cobalt-, and copper-containing proteins. We will end with an outlook of future developments.
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Affiliation(s)
- Sabine Van Doorslaer
- SIBAC Laboratory, University of Antwerp, Universiteitsplein 1, B-2160, Wilrijk-Antwerp, Belgium.
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