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Nam D, Bacik JP, Khade RL, Aguilera MC, Wei Y, Villada JD, Neidig ML, Zhang Y, Ando N, Fasan R. Mechanistic manifold in a hemoprotein-catalyzed cyclopropanation reaction with diazoketone. Nat Commun 2023; 14:7985. [PMID: 38042860 PMCID: PMC10693563 DOI: 10.1038/s41467-023-43559-7] [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: 03/21/2023] [Accepted: 11/14/2023] [Indexed: 12/04/2023] Open
Abstract
Hemoproteins have recently emerged as promising biocatalysts for new-to-nature carbene transfer reactions. However, mechanistic understanding of the interplay between productive and unproductive pathways in these processes is limited. Using spectroscopic, structural, and computational methods, we investigate the mechanism of a myoglobin-catalyzed cyclopropanation reaction with diazoketones. These studies shed light on the nature and kinetics of key catalytic steps in this reaction, including the formation of an early heme-bound diazo complex intermediate, the rate-determining nature of carbene formation, and the cyclopropanation mechanism. Our analyses further reveal the existence of a complex mechanistic manifold for this reaction that includes a competing pathway resulting in the formation of an N-bound carbene adduct of the heme cofactor, which was isolated and characterized by X-ray crystallography, UV-Vis, and Mössbauer spectroscopy. This species can regenerate the active biocatalyst, constituting a non-productive, yet non-destructive detour from the main catalytic cycle. These findings offer a valuable framework for both mechanistic analysis and design of hemoprotein-catalyzed carbene transfer reactions.
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Affiliation(s)
- Donggeon Nam
- Department of Chemistry, University of Rochester, Rochester, NY, 14627, USA
| | - John-Paul Bacik
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | | | - Yang Wei
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - Juan D Villada
- Department of Chemistry, University of Rochester, Rochester, NY, 14627, USA
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Michael L Neidig
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK.
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
| | - Nozomi Ando
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA.
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, Rochester, NY, 14627, USA.
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, 75080, USA.
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2
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Palermo JC, Colombo MC, Scocozza MF, Murgida DH, Estrin DA, Bari SE. Reduction of metmyoglobin by inorganic disulfide species. J Inorg Biochem 2023; 245:112256. [PMID: 37244768 DOI: 10.1016/j.jinorgbio.2023.112256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/03/2023] [Accepted: 05/11/2023] [Indexed: 05/29/2023]
Abstract
The mechanism of the metal centered reduction of metmyoglobin (MbFeIII) by inorganic disulfide species has been studied by combined spectroscopic and kinetic analyses, under argon atmosphere. The process is kinetically characterized by biexponential time traces, for variable ratios of excess disulfide to protein, in the pH interval 6.6-8.0. Using UV-vis and resonance Raman spectroscopies, we observed that MbFeIII is converted into a low spin hexacoordinated ferric complex, tentatively assigned as MbFeIII(HSS-)/MbFeIII(SS2-), in an initial fast step. The complex is slowly converted into a pentacoordinated ferrous form, assigned as MbFeII according to the resonance Raman records. The reduction is a pH-dependent process, but independent of the initial disulfide concentration, suggesting the unimolecular decomposition of the intermediate complex following a reductive homolysis. We estimated the rate of the fast formation of the complex at pH 7.4 (kon = 3.7 × 103 M-1 s-1), and a pKa2 = 7.5 for the equilibrium MbFeIII(HSS-)/MbFeIII(SS2-). Also, we estimated the rate for the slow reduction at the same pH (kred = 10-2 s-1). A reaction mechanism compliant with the experimental results is proposed. This mechanistic study provides a differential kinetic signature for the reactions of disulfide compared to sulfide species on metmyoglobin, which may be considered in other hemeprotein systems.
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Affiliation(s)
- Juan Cruz Palermo
- CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina
| | - Melisa Carllinni Colombo
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires, Argentina
| | - Magalí F Scocozza
- CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires, Argentina
| | - Daniel H Murgida
- CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires, Argentina
| | - Darío A Estrin
- CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires, Argentina
| | - Sara E Bari
- CONICET-Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Buenos Aires, Argentina.
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3
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Palermo JC, Carllinni Colombo M, Semelak JA, Scocozza MF, Boubeta FM, Murgida DH, Estrin DA, Bari SE. Autocatalytic Mechanism in the Anaerobic Reduction of Metmyoglobin by Sulfide Species. Inorg Chem 2023; 62:11304-11317. [PMID: 37439562 DOI: 10.1021/acs.inorgchem.3c00593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
The mechanism of the metal centered reduction of metmyoglobin (MbFeIII) by sulfide species (H2S/HS-) under an argon atmosphere has been studied by a combination of spectroscopic, kinetic, and computational methods. Asymmetric S-shaped time-traces for the formation of MbFeII at varying ratios of excess sulfide were observed at pH 5.3 < pH < 8.0 and 25 °C, suggesting an autocatalytic reaction mechanism. An increased rate at more alkaline pHs points to HS- as relevant reactive species for the reduction. The formation of the sulfanyl radical (HS•) in the slow initial phase was assessed using the spin-trap phenyl N-tert-butyl nitrone. This radical initiates the formation of S-S reactive species as disulfanuidyl/ disulfanudi-idyl radical anions and disulfide (HSSH•-/HSS•2- and HSS-, respectively). The autocatalysis has been ascribed to HSS-, formed after HSSH•-/HSS•2- disproportionation, which behaves as a fast reductant toward the intermediate complex MbFeIII(HS-). We propose a reaction mechanism for the sulfide-mediated reduction of metmyoglobin where only ferric heme iron initiates the oxidation of sulfide species. Beside the chemical interest, this insight into the MbFeIII/sulfide reaction under an argon atmosphere is relevant for the interpretation of biochemical aspects of ectopic myoglobins found on hypoxic tissues toward reactive sulfur species.
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Affiliation(s)
- Juan Cruz Palermo
- Instituto de Química Física de Los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Melisa Carllinni Colombo
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Jonathan A Semelak
- Instituto de Química Física de Los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Magalí F Scocozza
- Instituto de Química Física de Los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Fernando M Boubeta
- Instituto de Química Física de Los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Daniel H Murgida
- Instituto de Química Física de Los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Darío A Estrin
- Instituto de Química Física de Los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
| | - Sara E Bari
- Instituto de Química Física de Los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
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4
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Powell SM, Prather KY, Nguyen N, Thomas LM, Richter-Addo GB. Interactions of metronidazole and chloramphenicol with myoglobin: Crystal structure of a Mb-acetamide product. J PORPHYR PHTHALOCYA 2023; 27:1142-1147. [PMID: 37868702 PMCID: PMC10588810 DOI: 10.1142/s1088424623500700] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Nitroorganics present a general concern for a safe environment due to their health hazards. However, some nitroorganics such as metronidazole (Mtz) and chloramphenicol (CAM) also possess medicinal value. Mtz and CAM can undergo reductive bioactivation presumably via their nitroso derivatives. We show, using UV-vis spectroscopy, that sperm whale myoglobin (swMb) and its distal pocket mutants retaining H-bonding capacity react with Mtz in the presence of dithionite to generate products with spectra suggestive of the Fe-bound nitroso (Fe-RNO; λmax ~420 nm) forms. We have crystallized and solved the X-ray crystal structure of an H64Q swMb-acetamide compound to 1.76 Å resolution; formation of this compound results from the serendipitous crystallographic trapping, by the heme center, of acetamide from the reductive decomposition of Mtz. Only one of the swMb proteins, namely H64Q swMb with a relatively flexible Gln64 residue, reacted with CAM presumably due to the bulky nature of CAM that generally may restrict its access to the heme site.
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Affiliation(s)
- Samantha M. Powell
- Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, and Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, U.S.A. 73019
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Batelle Blvd, Richland, WA, U.S.A. 99352
| | - Kiana Y. Prather
- Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, and Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, U.S.A. 73019
- University of Oklahoma College of Medicine, 800 Stanton L. Young Blvd, Oklahoma City, OK 73117
| | - Nancy Nguyen
- Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, and Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, U.S.A. 73019
- University of Oklahoma College of Medicine, 800 Stanton L. Young Blvd, Oklahoma City, OK 73117
| | - Leonard M. Thomas
- Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, and Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, U.S.A. 73019
| | - George B. Richter-Addo
- Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, and Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK, U.S.A. 73019
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5
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Versatility of thiourea dioxide as redox agent in globins: case study with myoglobin. Inorganica Chim Acta 2023. [DOI: 10.1016/j.ica.2023.121474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
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6
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Nitrosylation of ferric zebrafish nitrobindin: A spectroscopic, kinetic, and thermodynamic study. J Inorg Biochem 2022; 237:111996. [PMID: 36150290 DOI: 10.1016/j.jinorgbio.2022.111996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/30/2022] [Accepted: 09/10/2022] [Indexed: 01/18/2023]
Abstract
Nitrobindins (Nbs) are all-β-barrel heme-proteins present in all the living kingdoms. Nbs inactivate reactive nitrogen species by sequestering NO, converting NO to HNO2, and isomerizing peroxynitrite to NO3- and NO2-. Here, the spectroscopic characterization of ferric Danio rerio Nb (Dr-Nb(III)) and NO scavenging through the reductive nitrosylation of the metal center are reported, both processes being relevant for the regulation of blood flow in fishes through poorly oxygenated tissues, such as retina. Both UV-Vis and resonance Raman spectroscopies indicate that Dr-Nb(III) is a mixture of a six-coordinated aquo- and a five-coordinated species, whose relative abundancies depend on pH. At pH ≤ 7.0, Dr-Nb(III) binds reversibly NO, whereas at pH ≥ 7.8 NO induces the conversion of Dr-Nb(III) to Dr-Nb(II)-NO. The conversion of Dr-Nb(III) to Dr-Nb(II)-NO is a monophasic process, suggesting that the formation of the transient Dr-Nb(III)-NO species is lost in the mixing time of the rapid-mixing stopped-flow apparatus (∼ 1.5 ms). The pseudo-first-order rate constant for the reductive nitrosylation of Dr-Nb(III) is not linearly dependent on the NO concentration but tends to level off. Values of the rate-limiting constant (i.e., klim) increase linearly with the OH- concentration, indicating that the conversion of Dr-Nb(III) to Dr-Nb(II)-NO is limited by the OH--based catalysis. From the dependence of klim on [OH-], the value of the second-order rate constant kOH- was obtained (5.2 × 103 M-1 s-1). Reductive nitrosylation of Dr-Nb(III) leads to the inactivation of two NO molecules: one being converted to HNO2, and the other being tightly bound to the heme-Fe(II) atom.
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7
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Influence of the heme distal pocket on nitrite binding orientation and reactivity in Sperm Whale myoglobin. Biochem J 2021; 478:927-942. [PMID: 33543749 PMCID: PMC7925009 DOI: 10.1042/bcj20200596] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 01/30/2021] [Accepted: 02/05/2021] [Indexed: 12/05/2022]
Abstract
Nitrite binding to recombinant wild-type Sperm Whale myoglobin (SWMb) was studied using a combination of spectroscopic methods including room-temperature magnetic circular dichroism. These revealed that the reactive species is free nitrous acid and the product of the reaction contains a nitrite ion bound to the ferric heme iron in the nitrito- (O-bound) orientation. This exists in a thermal equilibrium with a low-spin ground state and a high-spin excited state and is spectroscopically distinct from the purely low-spin nitro- (N-bound) species observed in the H64V SWMb variant. Substitution of the proximal heme ligand, histidine-93, with lysine yields a novel form of myoglobin (H93K) with enhanced reactivity towards nitrite. The nitrito-mode of binding to the ferric heme iron is retained in the H93K variant again as a thermal equilibrium of spin-states. This proximal substitution influences the heme distal pocket causing the pKa of the alkaline transition to be lowered relative to wild-type SWMb. This change in the environment of the distal pocket coupled with nitrito-binding is the most likely explanation for the 8-fold increase in the rate of nitrite reduction by H93K relative to WT SWMb.
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8
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Ascenzi P, De Simone G, Tundo GR, Coletta M. Kinetics of cyanide and carbon monoxide dissociation from ferrous human haptoglobin:hemoglobin(II) complexes. J Biol Inorg Chem 2020; 25:351-360. [DOI: 10.1007/s00775-020-01766-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/12/2020] [Indexed: 12/17/2022]
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9
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Rodriguez-Mackenzie AD, Arbelo-Lopez HD, Wymore T, Lopez-Garriga J. A reaction pathway to compound 0 intermediates in oxy-myoglobin through interactions with hydrogen sulfide and His64. J Mol Graph Model 2019; 94:107465. [PMID: 31670138 DOI: 10.1016/j.jmgm.2019.107465] [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: 08/09/2019] [Revised: 09/25/2019] [Accepted: 10/01/2019] [Indexed: 11/18/2022]
Abstract
Myoglobin (Mb) binds oxygen with high affinity as a low spin singlet complex and thus functions as an oxygen storage protein. Yet, hybrid Density Functional Theory/Molecular Mechanical (DFT/MM) calculations of oxy-Mb models predict that the O2 bond is much less resistant to breaking in the presence of hydrogen sulfide (H2S) compared with water. Specifically, a hydrogen atom from H2S can be transferred to the distal oxygen atom through homolytic cleavage of the S-H bond to form the intermediate Compound (Cpd) 0 structure and a thiyl radical. In the presence of a neutral His64 (Nε protonation, His64-ε) and H2S, only a metastable Cpd 0 would be formed as the active site is devoid of any additional proton donor to fully break the O2 bond. In contrast, the calculations predict that the triplet state is significantly favored over the open shell singlet diradical state throughout the entire reaction coordinate in the presence of H2S and a positively charged His64. Furthermore, a positively charged His64 can readily donate a proton to Cpd 0 to fully break the O2 bond resulting in a configuration analogous to reported reaction models of a hemoglobin mutant bound to H2O2 with H2S present. Typically, exotic techniques are required to generate Cpd 0 but under the conditions just described the intermediate is readily detected in UV-Vis spectra at room temperature. The effect is observed as a 2 nm red shift of the Soret band from 414 nm to 416 nm (pH 5.0, His64-εδ) and from 416 nm to 418 nm (pH 6.6, His64-ε).
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Affiliation(s)
| | - Hector D Arbelo-Lopez
- Department of Chemistry, University of Puerto Rico Mayaguez Campus, Mayaguez, 00680, Puerto Rico
| | - Troy Wymore
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, United States.
| | - Juan Lopez-Garriga
- Department of Chemistry, University of Puerto Rico Mayaguez Campus, Mayaguez, 00680, Puerto Rico.
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Alagurajan J, Singh Athwal N, Hargrove MS. Steady-State Kinetics of Phytoglobin-Catalyzed Reduction of Hydroxylamine to Ammonium. Biochemistry 2018; 57:4824-4832. [DOI: 10.1021/acs.biochem.8b00586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Jagannathan Alagurajan
- The Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Navjot Singh Athwal
- The Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Mark S. Hargrove
- The Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
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Kumar MR, Clover T, Olaitan AD, Becker C, Solouki T, Farmer PJ. The reaction between GSNO and H 2 S: On the generation of NO, HNO and N 2 O. Nitric Oxide 2018; 77:96-105. [DOI: 10.1016/j.niox.2018.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/20/2018] [Accepted: 04/24/2018] [Indexed: 12/17/2022]
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Zahler CT, Zhou H, Abdolvahabi A, Holden RL, Rasouli S, Tao P, Shaw BF. Direct Measurement of Charge Regulation in Metalloprotein Electron Transfer. Angew Chem Int Ed Engl 2018; 57:5364-5368. [PMID: 29451960 PMCID: PMC6033162 DOI: 10.1002/anie.201712306] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/15/2018] [Indexed: 12/16/2022]
Abstract
Determining whether a protein regulates its net electrostatic charge during electron transfer (ET) will deepen our mechanistic understanding of how polypeptides tune rates and free energies of ET (e.g., by affecting reorganization energy, and/or redox potential). Charge regulation during ET has never been measured for proteins because few tools exist to measure the net charge of a folded protein in solution at different oxidation states. Herein, we used a niche analytical tool (protein charge ladders analyzed with capillary electrophoresis) to determine that the net charges of myoglobin, cytochrome c, and azurin change by 0.62±0.06, 1.19±0.02, and 0.51±0.04 units upon single ET. Computational analysis predicts that these fluctuations in charge arise from changes in the pKa values of multiple non-coordinating residues (predominantly histidine) that involve between 0.42-0.90 eV. These results suggest that ionizable residues can tune the reactivity of redox centers by regulating the net charge of the entire protein-cofactor-solvent complex.
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Affiliation(s)
- Collin T. Zahler
- Department of Chemistry and BiochemistryBaylor University1301 S University Parks Dr.WacoTX76706USA
| | - Hongyu Zhou
- Department of ChemistrySouthern Methodist University6425 Boaz LaneDallasTX75205USA
| | - Alireza Abdolvahabi
- Department of Chemistry and BiochemistryBaylor University1301 S University Parks Dr.WacoTX76706USA
| | - Rebecca L. Holden
- Department of Chemistry and BiochemistryBaylor University1301 S University Parks Dr.WacoTX76706USA
| | - Sanaz Rasouli
- Department of Chemistry and BiochemistryBaylor University1301 S University Parks Dr.WacoTX76706USA
- Institute of Biomedical StudiesBaylor University1301 S University Parks Dr.WacoTX76706USA
| | - Peng Tao
- Department of ChemistrySouthern Methodist University6425 Boaz LaneDallasTX75205USA
| | - Bryan F. Shaw
- Department of Chemistry and BiochemistryBaylor University1301 S University Parks Dr.WacoTX76706USA
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Zahler CT, Zhou H, Abdolvahabi A, Holden RL, Rasouli S, Tao P, Shaw BF. Direct Measurement of Charge Regulation in Metalloprotein Electron Transfer. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201712306] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Collin T. Zahler
- Department of Chemistry and Biochemistry Baylor University 1301 S University Parks Dr. Waco TX 76706 USA
| | - Hongyu Zhou
- Department of Chemistry Southern Methodist University 6425 Boaz Lane Dallas TX 75205 USA
| | - Alireza Abdolvahabi
- Department of Chemistry and Biochemistry Baylor University 1301 S University Parks Dr. Waco TX 76706 USA
| | - Rebecca L. Holden
- Department of Chemistry and Biochemistry Baylor University 1301 S University Parks Dr. Waco TX 76706 USA
| | - Sanaz Rasouli
- Department of Chemistry and Biochemistry Baylor University 1301 S University Parks Dr. Waco TX 76706 USA
- Institute of Biomedical Studies Baylor University 1301 S University Parks Dr. Waco TX 76706 USA
| | - Peng Tao
- Department of Chemistry Southern Methodist University 6425 Boaz Lane Dallas TX 75205 USA
| | - Bryan F. Shaw
- Department of Chemistry and Biochemistry Baylor University 1301 S University Parks Dr. Waco TX 76706 USA
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14
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Preparation and characterization of myoglobin reconstituted with Fe(II) oxaporphyrin: The monoanionic macrocycle provides unique cyanide binding behavior for the ferrous species. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.06.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Determination of the formal redox potentials of the cyanhaemoglobin/cyanmethaemoglobin and the myoglobin/metmyoglobin couples at neutral pH. Bioelectrochemistry 2017; 120:83-86. [PMID: 29197256 DOI: 10.1016/j.bioelechem.2017.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 11/23/2017] [Accepted: 11/23/2017] [Indexed: 11/22/2022]
Abstract
Determination of a representative formal redox potential of the Fe(II)/Fe(III) redox couple in cyanhaemoglobin, at pH=7 and related to the state in solution, was the objective of this work. It was achieved at low concentrations of the protein (5μM) to circumvent undesired adsorption. Square-wave voltammetry instead of classical cyclic voltammetry was applied because this method is more sensitive and provides information on the formal redox potential and reversibility, even for rapid processes. We obtained E°'=-0.12±0.01V for cyanhaemoglobin and E°'=-0.10±0.01V, vs. SHE, for myoglobin in comparison. These values differ by only 20mV because the two Fe(II)/Fe(III) redox centres are embedded in closely resembling chemical environments. The small difference is probably owed to the additional axially coordinating cyanide ligand in cyanmethaemoglobin which slightly favours the Fe(III) state in the haem macrocycle.
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16
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Seal M, Mukherjee S, Dey SG. Fe–oxy adducts of heme–Aβ and heme–hIAPP complexes: intermediates in ROS generation. Metallomics 2016; 8:1266-1272. [DOI: 10.1039/c6mt00214e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Maj M, Oh Y, Park K, Lee J, Kwak KW, Cho M. Vibrational dynamics of thiocyanate and selenocyanate bound to horse heart myoglobin. J Chem Phys 2014; 140:235104. [DOI: 10.1063/1.4883505] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Ascenzi P, Leboffe L, Polticelli F. Cyanide binding to human plasma heme-hemopexin: a comparative study. Biochem Biophys Res Commun 2012; 428:239-244. [PMID: 23068104 DOI: 10.1016/j.bbrc.2012.10.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 10/05/2012] [Indexed: 06/01/2023]
Abstract
Hemopexin (HPX) displays a pivotal role in heme scavenging and delivery to the liver. In turn, heme-Fe-hemopexin (HPX-heme-Fe) displays heme-based spectroscopic and reactivity properties. Here, kinetics and thermodynamics of cyanide binding to ferric and ferrous hexa-coordinate human plasma HPX-heme-Fe (HHPX-heme-Fe(III) and HHPX-heme-Fe(II), respectively), and for the dithionite-mediated reduction of the HHPX-heme-Fe(III)-cyanide complex, at pH 7.4 and 20.0°C, are reported. Values of thermodynamic and kinetic parameters for cyanide binding to HHPX-heme-Fe(III) and HHPX-heme-Fe(II) are K = (4.1 ± 0.4) × 10(-6) M, k(on) = (6.9 ± 0.5) × 10(1) M(-1) s(-1), and k(off) = 2.8 × 10(-4) s(-1); and H = (6 ± 1) × 10(-1) M, h(on) = 1.2 × 10(-1) M(-1) s(-1), and h(off) = (7.1 ± 0.8) × 10(-2) s(-1), respectively. The value of the rate constant for the dithionite-mediated reduction of the HHPX-heme-Fe(III)-cyanide complex is l = 8.9 ± 0.8 M(-1/2) s(-1). HHPX-heme-Fe reactivity is modulated by proton acceptor/donor amino acid residue(s) (e.g., His236) assisting the deprotonation and protonation of the incoming and outgoing ligand, respectively.
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Affiliation(s)
- Paolo Ascenzi
- Laboratorio Interdipartimentale di Microscopia Elettronica, Università Roma Tre, Roma, Italy.
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Peroxynitrite detoxification by horse heart carboxymethylated cytochrome c is allosterically modulated by cardiolipin. Biochem Biophys Res Commun 2011; 415:463-7. [DOI: 10.1016/j.bbrc.2011.10.094] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 10/21/2011] [Indexed: 11/19/2022]
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Quintas PO, Catarino T, Todorovic S, Turner DL. Highly selective ligand binding by Methylophilus methylotrophus cytochrome c''. Biochemistry 2011; 50:5624-32. [PMID: 21599015 DOI: 10.1021/bi200480a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cytochrome c'' (cyt c'') from Methylophilus methylotrophus is unusual insofar as the heme has two axial histidine ligands in the oxidized form but one is detached when the protein is reduced. Despite cyt c'' having an axial site available for binding small ligands, we show here that only NO binds readily to the ferrous cyt c''. Binding of CO, as well as CN(-), on the other hand requires considerable structural reorganization, or reduction of the disulfide bridge close to the heme. Standard free energies for the binding of NO and CO reveal high selectivity of the ferrous cyt c'' for NO, indicating its putative physiological role. In this work, we characterize in detail the kinetics of NO binding and the structural features of the Fe(2+)-NO adduct by stopped-flow and resonance Raman spectroscopy, respectively.
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Affiliation(s)
- Pedro O Quintas
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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de Serrano VS, Davis MF, Gaff JF, Zhang Q, Chen Z, D'Antonio EL, Bowden EF, Rose R, Franzen S. X-ray structure of the metcyano form of dehaloperoxidase fromAmphitrite ornata: evidence for photoreductive dissociation of the iron–cyanide bond. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2010; 66:770-82. [DOI: 10.1107/s0907444910014605] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Accepted: 04/20/2010] [Indexed: 11/11/2022]
Abstract
X-ray crystal structures of the metcyano form of dehaloperoxidase-hemoglobin (DHP A) fromAmphitrite ornata(DHPCN) and the C73S mutant of DHP A (C73SCN) were determined using synchrotron radiation in order to further investigate the geometry of diatomic ligands coordinated to the heme iron. The DHPCN structure was also determined using a rotating-anode source. The structures show evidence of photoreduction of the iron accompanied by dissociation of bound cyanide ion (CN−) that depend on the intensity of the X-ray radiation and the exposure time. The electron density is consistent with diatomic molecules located in two sites in the distal pocket of DHPCN. However, the identities of the diatomic ligands at these two sites are not uniquely determined by the electron-density map. Consequently, density functional theory calculations were conducted in order to determine whether the bond lengths, angles and dissociation energies are consistent with bound CN−or O2in the iron-bound site. In addition, molecular-dynamics simulations were carried out in order to determine whether the dynamics are consistent with trapped CN−or O2in the second site of the distal pocket. Based on these calculations and comparison with a previously determined X-ray crystal structure of the C73S–O2form of DHP [de Serranoet al.(2007),Acta Cryst.D63, 1094–1101], it is concluded that CN−is gradually replaced by O2as crystalline DHP is photoreduced at 100 K. The ease of photoreduction of DHP A is consistent with the reduction potential, but suggests an alternative activation mechanism for DHP A compared with other peroxidases, which typically have reduction potentials that are 0.5 V more negative. The lability of CN−at 100 K suggests that the distal pocket of DHP A has greater flexibility than most other hemoglobins.
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Yi J, Heinecke J, Tan H, Ford PC, Richter-Addo GB. The distal pocket histidine residue in horse heart myoglobin directs the O-binding mode of nitrite to the heme iron. J Am Chem Soc 2010; 131:18119-28. [PMID: 19924902 DOI: 10.1021/ja904726q] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It is now well-established that mammalian heme proteins are reactive with various nitrogen oxide species and that these reactions may play significant roles in mammalian physiology. For example, the ferrous heme protein myoglobin (Mb) has been shown to reduce nitrite (NO(2)(-)) to nitric oxide (NO) under hypoxic conditions. We demonstrate here that the distal pocket histidine residue (His64) of horse heart metMb(III) (i.e., ferric Mb(III)) has marked effects on the mode of nitrite ion coordination to the iron center. X-ray crystal structures were determined for the mutant proteins metMb(III) H64V (2.0 A resolution) and its nitrite ion adduct metMb(III) H64V-nitrite (1.95 A resolution), and metMb(III) H64V/V67R (1.9 A resolution) and its nitrite ion adduct metMb(III) H64V/V67R-nitrite (2.0 A resolution). These are compared to the known structures of wild-type (wt) hh metMb(III) and its nitrite ion adduct hh metMb(III)-nitrite, which binds NO(2)(-) via an O-atom in a trans-FeONO configuration. Unlike wt metMb(III), no axial H(2)O is evident in either of the metMb(III) mutant structures. In the ferric H64V-nitrite structure, replacement of the distal His residue with Val alters the binding mode of nitrite from the nitrito (O-binding) form in the wild-type protein to a weakly bound nitro (N-binding) form. Reintroducing a H-bonding residue in the H64V/V67R double mutant restores the O-binding mode of nitrite. We have also examined the effects of these mutations on reactivities of the metMb(III)s with cysteine as a reducing agent and of the (ferrous) Mb(II)s with nitrite ion under anaerobic conditions. The Mb(II)s were generated by reduction of the Mb(III) precursors in a second-order reaction with cysteine, the rate constants for this step following the order H64V/V67R > H64V >> wt. The rate constants for the oxidation of the Mb(II)s by nitrite (giving NO as the other product) follow the order wt > H64V/V67R >> H64V and suggest a significant role of the distal pocket H-bonding residue in nitrite reduction.
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Affiliation(s)
- Jun Yi
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, Oklahoma 73019, USA
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Li CZ, Taniguchi I, Mulchandani A. Redox properties of engineered ruthenium myoglobin. Bioelectrochemistry 2009; 75:182-8. [DOI: 10.1016/j.bioelechem.2009.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 04/10/2009] [Accepted: 04/16/2009] [Indexed: 11/28/2022]
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Zahran ZN, Chooback L, Copeland DM, West AH, Richter-Addo GB. Crystal structures of manganese- and cobalt-substituted myoglobin in complex with NO and nitrite reveal unusual ligand conformations. J Inorg Biochem 2008; 102:216-33. [PMID: 17905436 PMCID: PMC2771112 DOI: 10.1016/j.jinorgbio.2007.08.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Revised: 08/03/2007] [Accepted: 08/16/2007] [Indexed: 01/17/2023]
Abstract
Nitrite is now recognized as a storage pool of bioactive nitric oxide (NO). Hemoglobin (Hb) and myoglobin (Mb) convert, under certain conditions, nitrite to NO. This newly discovered nitrite reductase activity of Hb and Mb provides an attractive alternative to mammalian NO synthesis from the NO synthase pathway that requires dioxygen. We recently reported the X-ray crystal structure of the nitrite adduct of ferric horse heart Mb, and showed that the nitrite ligand binds in an unprecedented O-binding (nitrito) mode to the d(5) ferric center in Mb(III)(ONO) [D.M. Copeland, A. Soares, A.H. West, G.B. Richter-Addo, J. Inorg. Biochem. 100 (2006) 1413-1425]. We also showed that the distal pocket in Mb allows for different conformations of the NO ligand (120 degrees and 144 degrees ) in Mb(II)NO depending on the mode of preparation of the compound. In this article, we report the crystal structures of the nitrite and NO adducts of manganese-substituted hh Mb (a d(4) system) and of the nitrite adduct of cobalt-substituted hh Mb (a d(6) system). We show that the distal His64 residue directs the nitrite ligand towards the rare nitrito O-binding mode in Mn(III)Mb and Co(III)Mb. We also report that the distal pocket residues allow a stabilization of an unprecendented bent MnNO moiety in Mn(II)MbNO. These crystal structural data, when combined with the data for the aquo, methanol, and azide MnMb derivatives, provide information on the role of distal pocket residues in the observed binding modes of nitrite and NO ligands to wild-type and metal-substituted Mb.
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Affiliation(s)
- Zaki N. Zahran
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, OK 73019
| | - Lilian Chooback
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, OK 73019
| | - Daniel M. Copeland
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, OK 73019
| | - Ann H. West
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, OK 73019
| | - George B. Richter-Addo
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, OK 73019
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Bolli A, Ciaccio C, Coletta M, Nardini M, Bolognesi M, Pesce A, Guertin M, Visca P, Ascenzi P. Ferrous Campylobacter jejuni truncated hemoglobin P displays an extremely high reactivity for cyanide - a comparative study. FEBS J 2008; 275:633-45. [DOI: 10.1111/j.1742-4658.2007.06223.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Pinnell D, Jordan RB. Kinetics of reduction of cobalt(III)-ammine complexes by dithionite. Inorg Chem 2002. [DOI: 10.1021/ic50201a048] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Davan T, Morrison JA. Chemistry of the boron subhalides. Preparation, boron nuclear magnetic resonance, and thermal stability of tetraboron tetrachloride. Inorg Chem 2002. [DOI: 10.1021/ic50201a049] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mie Y, Sonoda K, Kishita M, Krestyn E, Neya S, Funasaki N, Taniguchi I. Effect of rapid heme rotation on electrochemistry of myoglobin. Electrochim Acta 2000. [DOI: 10.1016/s0013-4686(00)00366-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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29
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Li CZ, Nishiyama K, Taniguchi I. Electrochemical and spectroelectrochemical studies on cobalt myoglobin. Electrochim Acta 2000. [DOI: 10.1016/s0013-4686(00)00363-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Musci G, Bellenchi GC, Calabrese L. The multifunctional oxidase activity of ceruloplasmin as revealed by anion binding studies. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 265:589-97. [PMID: 10504390 DOI: 10.1046/j.1432-1327.1999.00737.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effect of multiple binding of azide, N3-, on the structural and functional properties of ceruloplasmin (CP) has been reinvestigated by means of both spectroscopic and enzymatic techniques. High affinity binding of the anion to human CP resulted in a dramatic increase of the absorbance at 610 nm and in a concomitant decrease of the optical density at 330 nm. The oxidase activity toward Fe(II) was essentially unaffected, while turnover parameters versus nonferrous substrates dramatically changed, with an approximately 100-fold enhancement of the kcat/Km parameter. Chloride at physiological concentration proved to behave very similarly to N3- bound with high affinity, in that it not only induced the spectroscopic changes previously interpreted in terms of an intramolecular electron transfer from reduced type 1 to type 3 copper ions [Musci, G., Bonaccorsi di Patti, M.C. & Calabrese, L. (1995) J. Protein Chem. 14, 611-617], but it also enhanced some 60-fold the kcat/Km value. A different behavior was observed with chicken CP, where a decrease at 330 nm occurred without a concomitant modification at 603 nm. The chicken enzyme was less sensitive also in terms of enzymatic activity, which was nearly unchanged in the presence of either high affinity N3- or Cl-. At higher N3- concentrations, optical changes of both human and chicken CP were mainly focussed on the appearance of ligand-to-metal charge transfer bands below 500 nm, and the anion behaved as an inhibitor of the oxidase activity versus Fe(II) as well as noniron substrates. The well known bleaching of the blue chromophore could be observed, at neutral pH, only at very high N3-/CP ratios. The data presented in this paper are consistent with a mechanism of structural and functional modulation of CP by anions, that would be able to dictate the substrate specificity of the cuproprotein, and suggest the possibility that CP may act in vivo as a multifunctional oxidase.
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Affiliation(s)
- G Musci
- Department of Organic and Biological Chemistry, University of Messina, Italy.
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32
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Electroanalytical chemistry of myoglobin with modification of distal histidine by cyanated imidazole. J Electroanal Chem (Lausanne) 1999. [DOI: 10.1016/s0022-0728(99)00172-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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33
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The temperature dependence of the kinetics of cyanide dissociation from the cyanide complex of myoglobin studied by cyclic voltammetry. J Electroanal Chem (Lausanne) 1999. [DOI: 10.1016/s0022-0728(99)00142-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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34
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Taniguchi I, Li CZ, Ishida M, Yao Q. Electrochemical and spectroelectrochemical properties of manganese reconstituted myoglobin. J Electroanal Chem (Lausanne) 1999. [DOI: 10.1016/s0022-0728(98)00329-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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35
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Cohen DJ, King BC, Hawkridge FM. Spectroelectrochemical and electrochemical determination of ligand binding and electron transfer properties of myoglobin, cyanomyoglobin, and imidazolemyoglobin. J Electroanal Chem (Lausanne) 1998. [DOI: 10.1016/s0022-0728(98)00020-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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37
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Hamachi I, Matsugi T, Tanaka S, Shinkai S. Facilitated Photoreduction of Ruthenium Bis(4′-methylterpyridine) Pendant Myoglobin. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1996. [DOI: 10.1246/bcsj.69.1657] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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38
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Viola F, Aime S, Coletta M, Desideri A, Fasano M, Paoletti S, Tarricone C, Ascenzi P. Azide, cyanide, fluoride, imidazole and pyridine binding to ferric and ferrous native horse heart cytochrome c and to its carboxymethylated derivative: a comparative study. J Inorg Biochem 1996; 62:213-22. [PMID: 8627283 DOI: 10.1016/0162-0134(95)00155-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Azide, cyanide, fluoride, imidazole, and pyridine binding to ferric and ferrous native horse heart cytochrome c and to its carboxymethylated derivative has been investigated, from the thermodynamic viewpoint, at pH 7.5 and 25.0 degrees C. Ligand affinity for ferric and ferrous carboxymethylated cytochrome c is higher by about 30- and 400-fold, respectively, than that observed for the native protein. The results here reported: (i) allow the estimation, for the first time, of the ligand-independent free energy associated with the heme-iron sixth coordination bond in ferric and ferrous native cytochrome c, which turns out to be +8.4 kJ mol-1 and +14.6 kJ mol-1, at 25.0 degrees C, respectively, and (ii) suggest an interplay between redox, structural, ligand binding, and recognition properties of cytochrome c.
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Affiliation(s)
- F Viola
- FV. Institute of Applied Pharmaceutical Chemistry, University of Turin, Italy
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Antonini G, Bellelli A, Brunori M, Falcioni G. Kinetic and spectroscopic properties of the cyanide complexes of ferrous haemoglobins I and IV from trout blood. Biochem J 1996; 314 ( Pt 2):533-40. [PMID: 8670067 PMCID: PMC1217082 DOI: 10.1042/bj3140533] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The cyanide ion is a ligand of ferrous as well as ferric haemoproteins and this study presents a kinetic characterization of the dissociation of its complexes with the two main haemoglobin components from trout blood. Both these haemoglobins bind oxygen co-operatively at neutral or alkaline pH values but one of them is insensitive to pH and allosteric effectors (haemoglobin I, HbI) while the other (haemoglobin IV, HbIV) is strongly sensitive and shows the so-called Root effect (i.e. the incomplete oxygen saturation in air-equilibrated solutions at pH values of < 6.5). Comparison of the kinetics of dissociation of cyanide from ferrous forms of HbI and HbIV reveals that: (i) cyanide dissociates in both cases by a complex reaction, and, at least in the case of HbIV, this may be attributed to functional differences between the alpha and beta subunits; (ii) the reaction is only scarcely co-operative in HbI and not at all so in HbIV; and (iii) the Bohr and Root effects are not manifested in this reaction. The functional heterogeneity of ferrous alpha and beta chains of trout HbI has not been observed for any other ligand; moreover, the observation that co-operativity for cyanide dissociation is expressed by human haemoglobin but not by trout HbIV is surprising.
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Affiliation(s)
- G Antonini
- Department of Biochemical Sciences, University of Rome 'La Sapienza', Italy
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40
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Affiliation(s)
- E V Arnold
- Department of Chemistry, University of Wyoming, Laramie, 82071, USA
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Antonini G, Bellelli A, Concetti A, Falcioni G, Brunori M. Cyanide dissociation from the hemoglobin of Parascaris equorum. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1205:252-7. [PMID: 8155705 DOI: 10.1016/0167-4838(94)90241-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The reduction of cyanomethemoglobin by dithionite leads to the appearance of an intermediate, the complex of cyanide with ferrous hemoglobin, whose dissociation is easily followed in a stopped flow apparatus. This reaction was studied in the hemoglobin from the parasitic nematode Parascaris equorum, whose extremely high oxygen affinity is due to a very low dissociation rate. The rate of cyanide dissociation from ferrous Parascaris hemoglobin is not so dramatically different from that of other hemoglobins and myoglobins. Other features of the reaction are: (i) the rate constant of cyanide release is pH independent, an observation which is agreement with the possible absence of the distal histidine, given the mechanism suggested in a previous study (Bellelli, A., Antonini, G., Brunori, M, Springer, B.A. and Sligar, S.G. (1990) J. Biol. Chem. 265, 18898-18901), and (ii) the time-course shows no kinetic cooperativity. The structural basis of the extremely high oxygen affinity of Parascaris hemoglobin cannot be explained on the basis of the results here reported. This study also confirms that, even though cyanide binding to ferrous hemoglobins is controlled by distal interactions, the functional behaviour of this ligand is characteristic and differs from the behaviour of oxygen.
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Affiliation(s)
- G Antonini
- Department of Biochemical Sciences, University of Rome La Sapienza, Italy
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Saigo S, Hashimoto H, Shibayama N, Nomura M, Nagamura T. X-ray absorption spectroscopic studies of a transient intermediate in the reaction of cyanide metmyoglobin with dithionite by using rapid freezing. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1202:99-106. [PMID: 8373831 DOI: 10.1016/0167-4838(93)90069-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The reaction of cyanide metmyoglobin (Mb+CN-) with dithionite produces a transient intermediate, supposed to be cyanide-ligated ferrous myoglobin. The Fe K-edge X-ray absorption spectrum of the intermediate has been measured by using rapid freezing and compared with those of Mb+CN- and deoxymyoglobin (deoxyMb). The shapes of the XANES (X-ray Absorption Near Edge Structure) spectra of Mb+CN- and the intermediate are very similar, including the intensity ratios of the peak C1 to D. This indicates that CN- remains bound with a linear Fe-C-N configuration in the intermediate. The absorption edge of the intermediate is shifted to 1.2 eV lower energy than that of Mb+CN-, reflecting a valence change in the heme iron. The EXAFS (Extended X-ray Absorption Fine Structure) spectrum of the intermediate closely resembles that of Mb+CN- but significantly differs from that of deoxyMb. Analysis shows that the average iron-nearest neighbor atom distance is 1.99 +/- 0.01 A for both Mb+CN- and the intermediate and 2.05 +/- 0.01 A for deoxyMb. These results imply that the local structure around the heme iron of Mb+CN- does not change upon reduction until the cyanide ligand is released.
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Affiliation(s)
- S Saigo
- Department of Physics, Jichi Medical School, Tochigi, Japan
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McKenna CE, Gutheil WG, Song W. A method for preparing analytically pure sodium dithionite. Dithionite quality and observed nitrogenase-specific activities. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1075:109-17. [PMID: 1892862 DOI: 10.1016/0304-4165(91)90082-r] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Sodium dithionite (Na2S2O4) is widely used as a reductant in biochemical studies, but has not been available in its pure form. A convenient, detailed procedure is given for the recrystallization of commercial dithionite from 0.1 M NaOH-methanol under anaerobic conditions. Twice-recrystallized dithionite had a purity of 99 +/- 1% by UV spectroscopy (A315) and elemental analysis. The influence of dithionite quality on the apparent reduction activities of the nitrogenase components (Av1 and Av2) from Azotobacter vinelandii was investigated.
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Affiliation(s)
- C E McKenna
- Department of Chemistry, University of Southern California, Los Angeles
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Tsukahara K, Ishida K. Kinetics and Mechanism of Reduction of Metmyoglobins by Dithionite. Role of the Heme Propionates. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1991. [DOI: 10.1246/bcsj.64.2378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Hoffman BM, Natan MJ, Nocek JM, Wallin SA. Long-range electron transfer within metal-substituted protein complexes. LONG-RANGE ELECTRON TRANSFER IN BIOLOGY 1991. [DOI: 10.1007/3-540-53260-9_3] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Bellelli A, Antonini G, Brunori M, Springer B, Sligar S. Transient spectroscopy of the reaction of cyanide with ferrous myoglobin. Effect of distal side residues. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)30600-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Kraus DW, Wittenberg JB. Hemoglobins of the Lucina pectinata/bacteria symbiosis. I. Molecular properties, kinetics and equilibria of reactions with ligands. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)46185-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Bors W, Wachtveitl J, Saran M. The mechanism of cytochrome C reduction by alkyl radicals. Evidence for multiple reaction pathways. FREE RADICAL RESEARCH COMMUNICATIONS 1989; 6:251-6. [PMID: 2553548 DOI: 10.3109/10715768909073478] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The reactions of the hydroxyalkyl radicals .CH2OH and (CH3)2.COH with oxidized cytochrome c are for more complex than previously reported. Analysis of the pulse-radiolytic data by kinetic modelling revealed that only about 40% of the alkyl radicals reduce the ferric iron chromophore. Altogether, four different reactions have to be considered for the disappearance of the alkyl radicals, only two of which affect the metal site. The data show that these radicals, similar to the much more reactive hydrated electrons and hydrogen atoms, are capable to react with biological macromolecules in diverse ways.
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Affiliation(s)
- W Bors
- Institut für Strahlenbiologie, GSF Forschungszentrum, Neuherberg, FRG
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Ionic strength effect on the ascorbate reduction of sperm whale and horse heart metmyoglobins. Inorganica Chim Acta 1986. [DOI: 10.1016/s0020-1693(00)83291-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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