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Enache M, Negrila C, Lazarescu V. Surface states mediated charge transfer in redox behavior of hemin at GaAs(100) electrodes. RSC Adv 2020; 10:12318-12325. [PMID: 35497622 PMCID: PMC9050633 DOI: 10.1039/d0ra01508c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 03/20/2020] [Indexed: 11/24/2022] Open
Abstract
EIS and XPS investigations on the interaction of hemin with p- and n-doped GaAs(100) electrodes in PBS solution revealed significant differences concerning both the adsorbed species and the mechanism of the redox process caused by dopant nature. XPS data show that hemin is adsorbed on p-GaAs(100) by its carboxyl groups and adopts a vertical position favorable to a polymeric film formation whereas on n-GaAs(100), the adsorbed hemin is monomeric and has a rather planar configuration involving mainly the OH groups of the organic molecule. Hemin gives rise to a reversible redox process at the p-GaAs(100) electrode whereas at n-GaAs(100), there is only one reduction wave of a considerably lower current density appearing at a more negative potential. The effects of the applied potential on the phase angle measured at p-GaAs(100) point out major changes not only in the insulating properties of the adsorbed layer, as found at n-GaAs(100), but also in the electronic properties of the semiconductor triggered by the hemin redox process. Analysis of the experimental data points to a mechanism of charge transfer through surface states, the observed differences being related to the location of the surface states with respect to the formal potential of the hemin redox couple. Paper brings evidence that surface states are responsible for different redox processes of hemin, reversible at p-GaAs(100) and ireversible at n-GaAs(100).![]()
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Affiliation(s)
- Mirela Enache
- Institute of Physical Chemistry “Ilie Murgulescu”
- Bucharest
- Romania
| | - Catalin Negrila
- National Institute of Material Physics
- RO-77125 Bucharest
- Romania
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2
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Samajdar RN, Kumar C, Viswanath P, Bhattacharyya AJ. Studying Hemoglobin and a Bare Metal–Porphyrin Complex Immobilized on Functionalized Silicon Surfaces Using Synchrotron X-ray Reflectivity. J Phys Chem B 2019; 123:7492-7503. [DOI: 10.1021/acs.jpcb.9b03085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Rudra N. Samajdar
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Chandan Kumar
- Center for Nano and Soft Matter Science, Bengaluru 560013, India
| | - P. Viswanath
- Center for Nano and Soft Matter Science, Bengaluru 560013, India
| | - Aninda J. Bhattacharyya
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, India
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3
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Dillinger S, Lang J, Niedner-Schatteburg G. Cryo IR Spectroscopy of [Hemin] + Complexes in Isolation. J Phys Chem A 2017; 121:7191-7196. [PMID: 28876926 DOI: 10.1021/acs.jpca.7b08604] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We present cryo IR spectra of isolated [Hemin]+ adducts with CO, N2, and O2 ([Hemin(CO)1]+, [Hemin(CO)2]+, [Hemin(14N2)]+, [Hemin(15N2)]+, and [Hemin(O2)]+). Well resolved bands allow for the elucidation of structure and spin multiplicity in conjunction with density functional (DFT) calculations. There is a quartet spin state for the N2 and CO adducts and a sextet spin state for the O2 adduct, where the O2 retains its triplet state. The double CO adsorption induces significant changes in the vibrational patterns of the IR spectra, which we take as strong evidence for a spin quenching into a doublet. Our study characterizes [Hemin]+, which is the Fe3+ oxidation product of heme that is of ubiquitous presence in hemeproteins.
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Affiliation(s)
- Sebastian Dillinger
- Fachbereich Chemie and Forschungszentrum OPTIMAS, TU Kaiserslautern , 67663 Kaiserslautern, Germany
| | - Johannes Lang
- Fachbereich Chemie and Forschungszentrum OPTIMAS, TU Kaiserslautern , 67663 Kaiserslautern, Germany
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4
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Govind C, Karunakaran V. Ultrafast Relaxation Dynamics of Photoexcited Heme Model Compounds: Observation of Multiple Electronic Spin States and Vibrational Cooling. J Phys Chem B 2017; 121:3111-3120. [DOI: 10.1021/acs.jpcb.7b01416] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chinju Govind
- Photosciences
and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, Kerala India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi 110 001, India
| | - Venugopal Karunakaran
- Photosciences
and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, Kerala India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi 110 001, India
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5
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Zhao Z, Wang D, Wang M, Sun X, Wang L, Huang X, Ma L, Li Z. Proximal environment controlling the reactivity between inorganic sulfide and heme-peptide model. RSC Adv 2016. [DOI: 10.1039/c6ra14100e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Synthesized deuterohemin-peptide, which is lack of the distal protein structure, is used as a heme model to investigate the effects of the proximal environment on the reactivity of inorganic sulfide to heme center.
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Affiliation(s)
- Zijian Zhao
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- PR China
| | - Dandan Wang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- PR China
| | - Mingyang Wang
- National Engineering Laboratory for AIDS Vaccine
- Jilin University
- Changchun 130012
- PR China
| | - Xiaoli Sun
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- PR China
| | - Liping Wang
- National Engineering Laboratory for AIDS Vaccine
- Jilin University
- Changchun 130012
- PR China
| | - Xuri Huang
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- PR China
| | - Li Ma
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- PR China
| | - Zhengqiang Li
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- PR China
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6
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7
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Preda L, Negrila C, Lazarescu MF, Anastasescu M, Dobrescu G, Santos E, Lazarescu V. Hemin interaction with bare and 4,4′-thio-bis-benzene-thiolate covered n-GaAs (110) electrodes. Phys Chem Chem Phys 2011; 13:17104-14. [DOI: 10.1039/c1cp21652j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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8
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Song HY, Liu JZ, Weng LP, Ji LN. Activity, stability, and unfolding of reconstituted horseradish peroxidase with modified heme. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.molcatb.2008.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Aziz EF, Ottosson N, Bonhommeau S, Bergmann N, Eberhardt W, Chergui M. Probing the electronic structure of the hemoglobin active center in physiological solutions. PHYSICAL REVIEW LETTERS 2009; 102:068103. [PMID: 19257637 DOI: 10.1103/physrevlett.102.068103] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Indexed: 05/27/2023]
Abstract
Soft-x-ray absorption spectroscopy at the L_{2,3} edge of the iron center in bovine hemoglobin and hemin under physiological conditions is reported for the first time. Spectra of the same compounds in solid form are presented for comparison. Striking differences in the electronic structure of the metalloporphyrin are observed between the liquid and solid compounds. We unambiguously show that hemoglobin and hemin are in a high-spin ferric state in solution, and that the 2p spin-orbit coupling decreases for hemin compared to the hemoglobin, while this is not the case in solids. The spectra were simulated using ligand field multiplet theory, in good agreement with the experiment, allowing quantification of the amount of charge transfer between the porphyrin and Fe3+ ion in hemoglobin and in hemin.
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Affiliation(s)
- Emad F Aziz
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
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10
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11
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Vashi PR, Marques HM. The coordination of imidazole and substituted pyridines by the hemeoctapeptide N-acetyl-ferromicroperoxidase-8 (FeIINAcMP8). J Inorg Biochem 2005; 98:1471-82. [PMID: 15337599 DOI: 10.1016/j.jinorgbio.2004.05.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2004] [Revised: 05/11/2004] [Accepted: 05/18/2004] [Indexed: 11/23/2022]
Abstract
The N-terminus acetylated ferric hemeoctapeptide from cytochrome c, N-acetylmicroperoxidase-8 (Fe(III)-NAcMP8) can be reduced by dithionite in aqueous solution to produce Fe(II)-NAcMP8. The UV-Vis spectrum has a broad Soret band and relatively poorly defined Q bands which is consistent with a mixture of a five-coordinate high spin species with His as the axial ligand and a six-coordinate, predominantly high spin species with His/H(2)O as axial ligands. There are two spectroscopically observable pK(a)s at 8.7+/-0.1 and 10.9+/-0.2 which are attributed to ionization of a heme propionic acid group and coordinated H(2)O, respectively; a pK(a) > or = 14 is due to ionization of the proximal His ligand. Equilibrium constants were determined by UV-Vis spectrophotometry at 25.0+/-0.2 degrees C and 0.5 M ionic strength (NaClO(4)) for the coordination of imidazole and a number of substituted pyridines, and complement available data for the ferric hemepeptide, allowing a comparison to be made of the affinity of an iron porphyrin with Fe in the +2 and +3 oxidation states towards these ligands. Imidazole is coordinated more strongly by the ferric porphyrin (log K=4.08) than by the ferrous porphyrin (log K=3.40). The equilibrium constants for coordination of pyridines by the ferric and ferrous porphyrins increase and decrease, respectively, with increasing ligand basicity. Values determined by cyclic voltammetry show the same dependence on the identity of the ligand. In the ferric porphyrin, the stability of the complex increases with the basicity of the ligand and hence its ability to donate electron density onto the metal. In the case of the more electron rich ferrous porphyrin, greater stability occurs with pyridine ligands that have an electron withdrawing group and hence can accept electron density from the metal. This is consistent with the midpoint reduction potentials E(1/2) of the pyridine complexes determined by cyclic voltammetry; E(1/2) is linearly dependent on, and becomes more negative with an increase in, ligand basicity. Log K for coordination of pyridines by the ferrous hemepeptide correlates well with the energy of the ligand frontier orbital with pi symmetry, suggesting that pi-bonding effects are significant in determining the strength of binding of pyridines by a ferrous porphyrin.
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Affiliation(s)
- Preeti R Vashi
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg 2050, South Africa
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12
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Di Teodoro C, Aschi M, Amadei A, Roccatano D, Malatesta F, Ottaviano L. Conformational and Electronic Properties of a Microperoxidase in Aqueous Solution: A Computational Study. Chemphyschem 2005; 6:681-9. [PMID: 15881584 DOI: 10.1002/cphc.200400493] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A theoretical study of the conformational properties of a small heme peptide in aqueous solution is carried out by classical, long-timescale molecular dynamics simulations. The electronic properties of this species, that is, the relative energies of its excited electronic states and the redox potential, are reproduced and related to the conformational behavior using the perturbed matrix method and basic statistical mechanics. Our results show an interesting coupling between the conformational transitions and the electronic properties. These investigations, beyond the biophysically relevant results addressing the long-standing question of the actual role of the enzyme structure on the enzyme activity, are also of some methodological interest since they offer a further computational perspective for including the electronic degrees of freedom into the modeling of rather complex molecular systems.
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Affiliation(s)
- Carla Di Teodoro
- Dipartimento di Chimica, Ingegneria Chimica e Materiali Università dell'Aquila, 67010 l'Aquila (Italy)
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13
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Sánchez-Sandoval A, Ramírez-Rosales D, Zamorano-Ulloa R, Alvarez-Toledano C, Moya-Cabrera M, Reyes-Ortega Y. New pinch-porphyrin complexes with quantum mixed spin ground state S=, of iron (III) and their catalytic activity as peroxidase. Biophys Chem 2003; 106:253-65. [PMID: 14556897 DOI: 10.1016/s0301-4622(03)00186-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
New complexes of the pinch-porphyrin family were obtained from the dimethylester of (proto-, meso-, and deutero-porphyrinato)iron(III) with the ligand [N,N'-bis-pyridin-2-ylmethyl-propane-1,3-diamine] 1-3 and with the ligand [N-pyridin-2-ylmethyl-N'-[3-[(pyridin-2-ylmethyl)-amino]-propyl]-propane-1,3-diamine] 4-6. The UV/VIS studies of 1-6 indicate an increase in the distortion of the ligand field excited state. The 1H NMR spectra of 1-6 at RT and over the range 223-328 K show iron(III)-complexes with quantum mixed spin state (qms) S=5/2, S=3/2. The chemical shifts of the meso protons are consistent with qms state S=3/2, S=5/2, where the S=3/2 spin state is lowest in energy. For methyl-heme the chemical shifts are also consistent with a qms state but now the S=5/2 ground state is lowest in energy. ESR spectra of 1-6 show two different species, B and C, of iron(III) with qms, S=5/2, S=3/2 consistent with the 1H NMR results. Species B with 70% of S=5/2 and species C with 72.5% of S=3/2. The catalytic activity as peroxidase of 1-6 was quantified by guaiacol test; their theoretical maximum rate constants were k(cat) approximately 10(2)-10(3) M(-1) s(-1). A quantitative empirical correlation is found: the higher the 32 spin contribution to the qms state and the higher proportion of this species into the samples, the higher the peroxidase activity. Such a correlation was also obtained for pinch-porphyrins already reported.
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Affiliation(s)
- Amparo Sánchez-Sandoval
- Centro de Química, Instituto de Ciencias, Universidad Autónoma de Puebla. 14 Sur 6301. Col. San Manuel, Puebla, Pue 72570, Mexico
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14
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Monzani E, Curto M, Galliano M, Minchiotti L, Aime S, Baroni S, Fasano M, Amoresano A, Salzano AM, Pucci P, Casella L. Binding and relaxometric properties of heme complexes with cyanogen bromide fragments of human serum albumin. Biophys J 2002; 83:2248-58. [PMID: 12324442 PMCID: PMC1302313 DOI: 10.1016/s0006-3495(02)73985-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The spectroscopic and reactivity properties of hemin complexes formed with cyanogen bromide fragments B (residues 1-123), C (124-298), A (299-585), and D (1-298) of human serum albumin (HSA) have been investigated. The complex hemin-D exhibits binding, spectral, circular dichroism, and reactivity characteristics very similar to those of hemin-HSA, indicating that fragment D contains the entire HSA domain involved in heme binding. The characteristics of the other hemin complexes are different, and a detailed investigation of the properties of hemin-C has been carried out because this fragment contains the HSA binding region of several important drugs. Hemin-C contains a low-spin Fe(III) center, with two imidazole ligands, but the complex undergoes a reversible structural transition at basic pH leading to a high-spin, five-coordinated Fe(III) species. This change determines a marked increase in the relaxation rate of water protons. Limited proteolysis experiments and mass spectral analysis carried out on fragment C and hemin-C show that the region encompassing residues Glu-208 to Trp-214 is protected from activity of proteases in the complex and, therefore, is involved in the interaction with hemin. A structural model of fragment C enables us to propose that His-242 and His-288 are the axial ligands for the Fe(III) center.
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Affiliation(s)
- Enrico Monzani
- Dipartimento di Chimica Generale, Università di Pavia, Italy
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15
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Veeger C. Does P450-type catalysis proceed through a peroxo-iron intermediate? A review of studies with microperoxidase. J Inorg Biochem 2002; 91:35-45. [PMID: 12121760 DOI: 10.1016/s0162-0134(02)00393-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Recent stopped-flow kinetics demonstrated the existence of an intermediate before the occurrence of the final product of the reaction of both iron-containing microperoxidase-8 (Fe(III)MP-8) and manganese-containing microperoxidase-8 (Mn(III)MP-8) with H(2)O(2). The intermediate was assigned to be (hydro)peroxo-iron. With both mini-catalysts the final state obtained after 30-40 ms showed a resemblance to PorM(IV)MP-8[double bond]O(R(+)*); (R(+)*) is a radical located at the peptide. Quantum mechanical calculations indicate that hydroperoxo-iron is inactive as a catalytic intermediate in cytochrome P450 (P450)-type catalysis. Instead, the calculations suggest that peroxo-iron acts as the catalytic intermediate in P450-type catalysis. In addition, the calculations demonstrate that, although less likely, the possibility that oxenoid-iron acts as a catalytic intermediate in P450 catalysis cannot be fully excluded. An interesting aspect of the reactions catalysed by MP-8 is the possibility that, in view of the reversibility of the reactions between (hydro)peroxo-iron and oxenoid-iron, H(2)O plays a decisive role, at least in some cytochromes P450, in the removal of halogens, avoiding the production of compounds hazardous to the organism.
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Affiliation(s)
- Cees Veeger
- Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands.
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16
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Fakhari A, Shamsipur M, Ghanbari K. Zn(II)-selective membrane electrode based on tetra(2-aminophenyl) porphyrin. Anal Chim Acta 2002. [DOI: 10.1016/s0003-2670(02)00200-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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17
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Monzani E, Bonafè B, Fallarini A, Redaelli C, Casella L, Minchiotti L, Galliano M. Enzymatic properties of human hemalbumin. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1547:302-12. [PMID: 11410286 DOI: 10.1016/s0167-4838(01)00192-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The binding of hemin to the primary site of human serum albumin (HSA) has been reinvestigated using UV-Vis, CD and NMR techniques. The major fraction of bound hemin contains a five-coordinated high-spin iron(III) center, but a minor fraction of the metal appears to be in a six-coordinated, low-spin state, where a 'distal' residue, possibly a second histidine residue, completes the coordination sphere. The reduced, iron(II) form of the adduct contains six-coordinated low-spin heme. The distal residue hinders the access to the iron(III) center of hemin-HSA to small anionic ligands like azide and cyanide and destabilizes the binding of neutral diatomics like dioxygen and carbon monoxide to the iron(II) form. In spite of these limitations, the hemin-HSA complex promotes hydrogen peroxide activation processes that bear the characteristics of enzymatic reactions and may have biological relevance. The complex is in fact capable of catalyzing peroxidative reactions on phenolic compounds related to tyrosine and hydrogen peroxide dismutation. Kinetic and mechanistic studies confirm that the low efficiency with which peroxidative processes occur depends on the limited rate of the reaction between hydrogen peroxide and the iron(III) center, to form the active species, and by the competitive peroxide degradation reaction.
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Affiliation(s)
- E Monzani
- Dipartimento di Chimica Generale, Università di Pavia, Italy
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18
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Monzani E, Alzuet G, Casella L, Redaelli C, Bassani C, Sanangelantoni AM, Gullotti M, de Gioia L, Santagostini L, Chillemi F. Properties and reactivity of myoglobin reconstituted with chemically modified protohemin complexes. Biochemistry 2000; 39:9571-82. [PMID: 10924154 DOI: 10.1021/bi000784t] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthetic complexes protohemin-6(7)-L-arginyl-L-alanine (HM-RA) and protohemin-6(7)-L-histidine methyl ester (HM-H) were prepared by condensation of suitably protected Arg-Ala or His residues with protohemin IX. HM-RA and HM-H were used for reconstitution of apomyoglobin from horse heart, yielding the Mb-RA and Mb-H derivatives, respectively, of the protein. The spectral, binding and catalytic properties of Mb-RA and Mb-H are significantly different from those of Mb. As shown by MM and MD calculations, these differences are determined by some local structural changes around the heme which are generated by increased mobility of a key peptide segment (Phe43-Lys47), containing the residue (Lys45) that in native Mb interacts with one of the porphyrin carboxylate groups. In the reconstituted Mbs this carboxylate group is bound to the Arg-Ala or His residue and is no longer available for electrostatic interaction with Lys45. The mobility of the peptide segment near the active site allows the distal histidine to come to a closer contact with the heme, and in fact Mb-RA and Mb-H exist as an equilibrium between a high-spin form and a major low-spin, six-coordinated form containing a bis-imidazole ligated heme. The two forms are clearly distinguishable in the NMR spectra, that also show that each of them consists of a mixture of the two most stable isomers resulting from cofactor reconstitution, as also anticipated by MM and MD calculations. Exogenous ligands such as cyanide, azide, or hydrogen peroxide can displace the bound distal histidine, but their affinity is reduced. On the other hand, mobilization of the peptide chain around the heme in the reconstituted Mbs increases the accessibility of large donor molecules at the heme periphery, with respect to native Mb, where a rigid backbone limits access to the distal pocket. The increased active site accessibility of Mb-RA and Mb-H facilitates the binding and electron transfer of phenolic substrates in peroxidase-type oxidations catalyzed by the reconstituted proteins in the presence of hydrogen peroxide.
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Affiliation(s)
- E Monzani
- Dipartimento di Chimica Generale, Università di Pavia, Italy
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19
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20
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Rich AM, Ellis PJ, Tennant L, Wright PE, Armstrong RS, Lay PA. Determination of Fe-ligand bond lengths and the Fe-N-O bond angles in soybean ferrous and ferric nitrosylleghemoglobin a using multiple-scattering XAFS analyses. Biochemistry 1999; 38:16491-9. [PMID: 10600110 DOI: 10.1021/bi990730n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The NO adducts of leghemoglobin (Lb) are implicated in biological processes, but only the adduct with ferrous Lb (Lb(II)NO) has been characterized previously. We report the first characterization of ferric nitrosylleghemoglobin (Lb(III)NO) and XAS experiments performed on frozen aqueous solutions of Lb(II)NO and Lb(III)NO at 10 K. The XANES and electronic spectra of the NO adducts are similar in shape and energies to the myoglobin (Mb) analogues. The environment of the Fe atom has been refined using multiple-scattering (MS) analyses of the XAFS data. For Lb(II)NO, the MS analysis resulted in an averaged Fe-N(p)(pyrrole) distance of 2.02 A, an Fe-N(epsilon)(imidazole) distance of 1.98 A, an Fe-N(NO) distance of 1.77 A, and an Fe-N-O angle of 147 degrees. The Fe-N(NO) distance and Fe-N-O angle obtained from the analysis of Lb(II)NO are in good agreement with those determined crystallographically for [Fe(TPP)(NO)] (TPP, tetraphenylporphyrinato), with and without 1-methylimidazole (1-MeIm) as the sixth ligand, and the MS XAFS structures reported previously for the myoglobin (Mb(II)NO) analogue and [Fe(TPP)(NO)]. The MS analysis of Lb(III)NO yielded an average Fe-N(p) distance of 2.00 A, an Fe-N(epsilon) distance of 1.89 A, an Fe-N(NO) distance of 1.68 A, and an Fe-N-O angle of 173 degrees. These bond lengths and angles are consistent with those determined previously for the myoglobin analogue (Mb(III)NO) and the crystal structures of the model complexes, [Fe(III)(TPP)(NO)(OH(2))](+) and [Fe(OEP)(NO)](+) (OEP, octaethylporphyrinato). The final XAFS R values were 16.1 and 18.2% for Lb(II)NO and Lb(III)NO, respectively.
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Affiliation(s)
- A M Rich
- School of Chemistry, University of Sydney, New South Wales, Australia
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21
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Marques HM, Munro OQ, Munro T, de Wet M, Vashi PR. Coordination of N-Donor Ligands by the Monomeric Ferric Porphyrin N-Acetylmicroperoxidase-8. Inorg Chem 1999. [DOI: 10.1021/ic981293o] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Helder M. Marques
- Centre for Molecular Design, Department of Chemistry, University of the Witwatersrand, P.O. Wits, 2050 Johannesburg, South Africa
| | - Orde Q. Munro
- Centre for Molecular Design, Department of Chemistry, University of the Witwatersrand, P.O. Wits, 2050 Johannesburg, South Africa
| | - Tracey Munro
- Centre for Molecular Design, Department of Chemistry, University of the Witwatersrand, P.O. Wits, 2050 Johannesburg, South Africa
| | - Marina de Wet
- Centre for Molecular Design, Department of Chemistry, University of the Witwatersrand, P.O. Wits, 2050 Johannesburg, South Africa
| | - Preeti R. Vashi
- Centre for Molecular Design, Department of Chemistry, University of the Witwatersrand, P.O. Wits, 2050 Johannesburg, South Africa
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Angiolillo PJ, Vanderkooi JM. The photoexcited triplet state as a probe of chromophore-protein interaction in myoglobin. Biophys J 1998; 75:1491-502. [PMID: 9726951 PMCID: PMC1299824 DOI: 10.1016/s0006-3495(98)74068-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The photoexcited metastable triplet state of Mg(2+)-mesoporphyrin IX (MgMPIX) or Mg(2+)-protoporphyrin IX (MgPPIX) located in the heme pocket of horse myoglobin (Mb) was investigated by optical and electron paramagnetic resonance (EPR) spectroscopy, and its properties were compared with the model complexes, MgMPIX, MgPPIX, and Mg2+ etioporphyrin I (MgETIOI), in noncoordinating and coordinating organic glasses. Zero-field splitting parameters, line shape, and Jahn-Teller distortion in the temperature range of 3.8-110 K are discussed in terms of porphyrin-protein interactions. The triplet line shapes for MgMPIXMb and MGPPIXMb show no temperature-dependent spectral line shape changes suggestive of Jahn-Teller dynamics, and it is concluded that the energy splitting is >> 150 cm-1, suggesting symmetry breaking from the anisotropy of intermal electric fields of the protein, and consistent with previous predictions (Geissinger et al. 1995. J. Phys. Chem. 99:16527-16529). Both MgMPIXMb and MgPPIXMb demonstrate electron spin polarization at low temperature, and from the polarization pattern it can be concluded that intersystem crossing occurs predominantly into in-plane spin sublevels of the triplet state. The splitting in the Q0.0 absorption band and the temperature dependence and splitting of the photoexcited triplet state of myoglobin in which the iron was replaced by Mg2+ are interpreted in terms of effects produced by electric field asymmetry in the heme pocket.
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Affiliation(s)
- P J Angiolillo
- Department of Physics, Mathematics and Computer Science, University of the Sciences in Philadelphia, Pennsylvania 19104-4495, USA.
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Wesley Owens J, Perry M, Seybert DW. Adducts of nitric oxide with cobaltous tetraphenylporphyrin and phthalocyanines: potential nitric oxide sorbents. Inorganica Chim Acta 1998. [DOI: 10.1016/s0020-1693(97)05964-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Reddy KS, Angiolillo PJ, Wright WW, Laberge M, Vanderkooi JM. Spectral splitting in the alpha (Q0,0) absorption band of ferrous cytochrome c and other heme proteins. Biochemistry 1996; 35:12820-30. [PMID: 8841125 DOI: 10.1021/bi960895l] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The alpha or Q0,0 absorption band of horse iron(II) cytochrome c splits and shifts to the blue as temperature decreases over the temperature range of 290-10 K. At room temperature, its maximum is at 18 150 cm-1 and the spectral width is 273 cm-1, whereas at 10 K, the two bands of the Q0,0 transition occur at 18 364 and 18 253 cm-1 and the width of the lowest-energy band is 96 cm-1. Temperature dependent splitting also occurs for zinc cytochrome c, a derivative in which Fe has been replaced by Zn; at 10 K, the peaks in the Q0,0 band region occur at 17 106 and 16 996 cm-1. The peak positions are independent of the cryosolvent (aqueous ethylene glycol or glycerol mixtures). The splitting of the Q0,0 band seen in the protein (approximately 110 cm-1 for iron and zinc cytochrome c) is comparable to the crystal field splitting observed for metalloporphyrins in mixed crystals. In contrast, the Q0,0 band of zinc coproporphyrin III in a glassy solvent (dimethylformamide/ethylene glycol) or in poly(vinyl chloride) shows a blue shift with temperature decrease but no evidence of Q0,0 splitting. Available spectral data show that the Q0,0 band is composed of two nearly degenerate electronic transitions and the split is due to the asymmetry in the heme pocket of the protein that arises from the surrounding polypeptide chain. This asymmetry results in the stabilization of one form of the excited state over the other, according to a Jahn-Teller mechanism.
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Affiliation(s)
- K S Reddy
- Johnson Research Foundation, Department of Biochemistry & Biophysics, School of Medicine, University of Pennsylvania, Philadelphia 19104, USA
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25
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Owens JW, Robins M, O'Connor CJ. A comparison of the magnetic and crystal field properties of protoporphyrin-IX, hemeoctapeptide and heme proteins. Inorganica Chim Acta 1995. [DOI: 10.1016/0020-1693(95)04698-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Owens JW, Yang L, Adeola G, Robins M, Smith R, Robinson R, Elayan N, McMahon L. Isolation and photodynamic effects of hematoporphyrin derivative components: a chromatographic analysis of the starting materials. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1995; 669:295-309. [PMID: 7581906 DOI: 10.1016/0378-4347(95)00097-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Twenty different fractions of hematoporphyrin derivatives (HpD) and eight fractions of an HpD dimer mixture were isolated utilizing isocratic reversed-phase ion-pair high-performance liquid chromatography. These fractions were characterized by UV-visible and fluorescence spectrophotometry. Fluorescence quantum yields and photokill efficiency for each fraction in PTK2 epithelial cells were obtained. Results indicate that some part of the photoactivity exhibited by HpD may be due to impurities present in the HpD starting material, hematoporphyrin-IX dihydrochloride, depending on its source. It was also found that hematoporphyrin D, a commercial acetylated product formed during synthesis of HpD, contained a higher percentage of monomers than would be expected.
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Affiliation(s)
- J W Owens
- Health Research Center, Southern University, Baton Rouge, LA 70813, USA
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Czernuszewicz RS, Wagner WD, Ray GB, Nakamoto K. Resonance Raman and infrared spectra of azidoiron(III) and azidomanganese(III) porphyrins. J Mol Struct 1991. [DOI: 10.1016/0022-2860(91)87130-a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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30
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Gourley GR, Kreamer B, Arend R. Excremental studies in human neonates. Identification of zinc coproporphyrin as a marker for meconium. Gastroenterology 1990; 99:1705-9. [PMID: 2227283 DOI: 10.1016/0016-5085(90)90476-h] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Zinc coproporphyrin, isomers I and III (I:III ratio, approximately 8:1), was identified in human meconium using high-performance liquid chromatography, ultraviolet-visible absorbance spectroscopy, and emission fluorescence spectroscopy. The high levels of zinc coproporphyrin in the first stools of life decrease steadily as meconium is evacuated and reach a plateau at comparatively negligible levels after complete evacuation of meconium. Zinc coproporphyrin can be used as a marker for human meconium.
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Affiliation(s)
- G R Gourley
- Department of Pediatrics, University of Wisconsin School of Medicine, Madison
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