1
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González-Delgado JM, Thompson PM, Andrałojć W, Gdaniec Z, Ghiladi RA, Franzen S. Comparison of the Backbone Dynamics of Dehaloperoxidase-Hemoglobin Isoenzymes. J Phys Chem B 2024; 128:3383-3397. [PMID: 38563384 DOI: 10.1021/acs.jpcb.3c07176] [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: 04/04/2024]
Abstract
Dehaloperoxidase (DHP) is a multifunctional hemeprotein with a functional switch generally regulated by the chemical class of the substrate. Its two isoforms, DHP-A and DHP-B, differ by only five amino acids and have an almost identical protein fold. However, the catalytic efficiency of DHP-B for oxidation by a peroxidase mechanism ranges from 2- to 6-fold greater than that of DHP-A depending on the conditions. X-ray crystallography has shown that many substrates and ligands have nearly identical binding in the two isoenzymes, suggesting that the difference in catalytic efficiency could be due to differences in the conformational dynamics. We compared the backbone dynamics of the DHP isoenzymes at pH 7 through heteronuclear relaxation dynamics at 11.75, 16.45, and 19.97 T in combination with four 300 ns MD simulations. While the overall dynamics of the isoenzymes are similar, there are specific local differences in functional regions of each protein. In DHP-A, Phe35 undergoes a slow chemical exchange between two conformational states likely coupled to a swinging motion of Tyr34. Moreover, Asn37 undergoes fast chemical exchange in DHP-A. Given that Phe35 and Asn37 are adjacent to Tyr34 and Tyr38, it is possible that their dynamics modulate the formation and migration of the active tyrosyl radicals in DHP-A at pH 7. Another significant difference is that both distal and proximal histidines have a 15-18% smaller S2 value in DHP-B, thus their greater flexibility could account for the higher catalytic activity. The distal histidine grants substrate access to the distal pocket. The greater flexibility of the proximal histidine could also accelerate H2O2 activation at the heme Fe by increased coupling of an amino acid charge relay to stabilize the ferryl Fe(IV) oxidation state in a Poulos-Kraut "push-pull"-type peroxidase mechanism.
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Affiliation(s)
| | - Peter M Thompson
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
- Molecular Education, Technology and Research Innovation Center (METRIC), North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Witold Andrałojć
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Zofia Gdaniec
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Reza A Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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2
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Malewschik T, Carey LM, de Serrano V, Ghiladi RA. Bridging the functional gap between reactivity and inhibition in dehaloperoxidase B from Amphitrite ornata: Mechanistic and structural studies with 2,4- and 2,6-dihalophenols. J Inorg Biochem 2022; 236:111944. [PMID: 35969974 DOI: 10.1016/j.jinorgbio.2022.111944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 06/29/2022] [Accepted: 07/20/2022] [Indexed: 12/15/2022]
Abstract
The multifunctional catalytic globin dehaloperoxidase (DHP) from the marine worm Amphitrite ornata was shown to catalyze the H2O2-dependent oxidation of 2,4- and 2,6-dihalophenols (DXP; X = F, Cl, Br). Product identification by LC-MS revealed multiple monomeric products with varying degrees of oxidation and/or dehalogenation, as well as oligomers with n up to 6. Mechanistic and 18O-labeling studies demonstrated sequential dihalophenol oxidation via peroxidase and peroxygenase activities. Binding studies established that 2,4-DXP (X = Cl, Br) have the highest affinities of any known DHP substrate. X-ray crystallography identified different binding positions for 2,4- and 2,6-DXP substrates in the hydrophobic distal pocket of DHP. Correlation between the number of halogens and the substrate binding orientation revealed a halogen-dependent binding motif for mono- (4-halophenol), di- (2,4- and 2,6-dihalophenol) and trihalophenols (2,4,6-trihalopenol). Taken together, the findings here on dihalophenol reactivity with DHP advance our understanding of how these compounds bridge the inhibitory and oxidative functions of their mono- and trihalophenol counterparts, respectively, and provide further insight into the protein structure-function paradigm relevant to multifunctional catalytic globins in comparison to their monofunctional analogs.
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Affiliation(s)
- Talita Malewschik
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States
| | - Leiah M Carey
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States
| | - Reza A Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, United States.
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3
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Nys K, Pfanzagl V, Roefs J, Obinger C, Van Doorslaer S. In Vitro Heme Coordination of a Dye-Decolorizing Peroxidase-The Interplay of Key Amino Acids, pH, Buffer and Glycerol. Int J Mol Sci 2021; 22:ijms22189849. [PMID: 34576013 PMCID: PMC8468270 DOI: 10.3390/ijms22189849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 11/17/2022] Open
Abstract
Dye-decolorizing peroxidases (DyPs) have gained interest for their ability to oxidize anthraquinone-derived dyes and lignin model compounds. Spectroscopic techniques, such as electron paramagnetic resonance and optical absorption spectroscopy, provide main tools to study how the enzymatic function is linked to the heme-pocket architecture, provided the experimental conditions are carefully chosen. Here, these techniques are used to investigate the effect of active site perturbations on the structure of ferric P-class DyP from Klebsiella pneumoniae (KpDyP) and three variants of the main distal residues (D143A, R232A and D143A/R232A). Arg-232 is found to be important for maintaining the heme distal architecture and essential to facilitate an alkaline transition. The latter is promoted in absence of Asp-143. Furthermore, the non-innocent effect of the buffer choice and addition of the cryoprotectant glycerol is shown. However, while unavoidable or indiscriminate experimental conditions are pitfalls, careful comparison of the effects of different exogenous molecules on the electronic structure and spin state of the heme iron contains information about the inherent flexibility of the heme pocket. The interplay between structural flexibility, key amino acids, pH, temperature, buffer and glycerol during in vitro spectroscopic studies is discussed with respect to the poor peroxidase activity of bacterial P-class DyPs.
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Affiliation(s)
- Kevin Nys
- BIMEF Laboratory, Department of Chemistry, University of Antwerp, 2610 Antwerp, Belgium; (K.N.); (J.R.)
| | - Vera Pfanzagl
- Division of Biochemistry, Department of Chemistry, BOKU—University of Natural Resources and Life Sciences, 1190 Vienna, Austria; (V.P.); (C.O.)
| | - Jeroen Roefs
- BIMEF Laboratory, Department of Chemistry, University of Antwerp, 2610 Antwerp, Belgium; (K.N.); (J.R.)
| | - Christian Obinger
- Division of Biochemistry, Department of Chemistry, BOKU—University of Natural Resources and Life Sciences, 1190 Vienna, Austria; (V.P.); (C.O.)
| | - Sabine Van Doorslaer
- BIMEF Laboratory, Department of Chemistry, University of Antwerp, 2610 Antwerp, Belgium; (K.N.); (J.R.)
- Correspondence: ; Tel.: +32-3-265-2461
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4
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5
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Van Doorslaer S. Understanding heme proteins with hyperfine spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:79-88. [PMID: 28579104 DOI: 10.1016/j.jmr.2017.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 06/07/2023]
Abstract
Heme proteins are versatile proteins that are involved in a large number of biological processes. Many spectroscopic methods are used to gain insight into the different mechanistic processes governing heme-protein functions. Since many (intermediate) states of heme proteins are paramagnetic, electron paramagnetic resonance (EPR) methods, such as hyperfine spectroscopy, offer unique tools for these investigations. This perspective gives an overview of the use of state-of-the-art hyperfine spectroscopy in heme research, focusing on the advantages, limits and challenges of the different techniques.
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Affiliation(s)
- Sabine Van Doorslaer
- BIMEF Laboratory, Department of Physics, University of Antwerp, B-2610 Antwerp, Belgium.
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6
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McCombs NL, Moreno-Chicano T, Carey LM, Franzen S, Hough MA, Ghiladi RA. Interaction of Azole-Based Environmental Pollutants with the Coelomic Hemoglobin from Amphitrite ornata: A Molecular Basis for Toxicity. Biochemistry 2017; 56:2294-2303. [PMID: 28387506 DOI: 10.1021/acs.biochem.7b00041] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The toxicities of azole pollutants that have widespread agricultural and industrial uses are either poorly understood or unknown, particularly with respect to how infaunal organisms are impacted by this class of persistent organic pollutant. To identify a molecular basis by which azole compounds may have unforeseen toxicity on marine annelids, we examine here their impact on the multifunctional dehaloperoxidase (DHP) hemoglobin from the terebellid polychaete Amphitrite ornata. Ultraviolet-visible and resonance Raman spectroscopic studies showed an increase in the six-coordinate low-spin heme population in DHP isoenzyme B upon binding of imidazole, benzotriazole, and benzimidazole (Kd values of 52, 82, and 110 μM, respectively), suggestive of their direct binding to the heme-Fe. Accordingly, atomic-resolution X-ray crystal structures, supported by computational studies, of the DHP B complexes of benzotriazole (1.14 Å), benzimidazole (1.08 Å), imidazole (1.08 Å), and indazole (1.12 Å) revealed two ligand binding motifs, one with direct ligand binding to the heme-Fe, and another in which the ligand binds in the hydrophobic distal pocket without coordinating the heme-Fe. Taken together, the results demonstrate a new mechanism by which azole pollutants can potentially disrupt hemoglobin function, thereby improving our understanding of their impact on infaunal organisms in marine and aquatic environments.
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Affiliation(s)
- Nikolette L McCombs
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - Tadeo Moreno-Chicano
- School of Biological Sciences, University of Essex , Wivenhoe Park, Colchester, Essex CO4 3SQ, U.K
| | - Leiah M Carey
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
| | - Michael A Hough
- School of Biological Sciences, University of Essex , Wivenhoe Park, Colchester, Essex CO4 3SQ, U.K
| | - Reza A Ghiladi
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States
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7
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Zhao J, Moretto J, Le P, Franzen S. Measurement of Internal Substrate Binding in Dehaloperoxidase–Hemoglobin by Competition with the Heme–Fluoride Binding Equilibrium. J Phys Chem B 2015; 119:2827-38. [DOI: 10.1021/jp512996v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Jing Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Justin Moretto
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Peter Le
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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8
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Zhao J, de Serrano V, Franzen S. A model for the flexibility of the distal histidine in dehaloperoxidase-hemoglobin A based on X-ray crystal structures of the carbon monoxide adduct. Biochemistry 2014; 53:2474-82. [PMID: 24670063 PMCID: PMC4203366 DOI: 10.1021/bi5001905] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Dehaloperoxidase
hemoglobin A (DHP A) is a multifunctional hemoglobin
that appears to have evolved oxidative pathways for the degradation
of xenobiotics as a protective function that complements the oxygen
transport function. DHP A possesses at least two internal binding
sites, one for substrates and one for inhibitors, which include various
halogenated phenols and indoles. Herein, we report the X-ray crystallographic
structure of the carbonmonoxy complex (DHPCO). Unlike other DHP structures
with 6-coordinated heme, the conformation of the distal histidine
(H55) in DHPCO is primarily external or solvent exposed, despite the
fact that the heme Fe is 6-coordinated. As observed generally in globins,
DHP exhibits two distal histidine conformations (one internal and
one external). In previous structural studies, we have shown that
the distribution of H55 conformations is weighted strongly toward
the external position when the DHP heme Fe is 5-coordinated. The large
population of the external conformation of the distal histidine observed
in DHPCO crystals at pH 6.0 indicates that some structural factor
in DHP must account for the difference from other globins, which exhibit
a significant external conformation only when pH < 4.5. While the
original hypothesis suggested that interaction with a heme-Fe-bound
ligand was the determinant of H55 conformation, the current study
forces a refinement of that hypothesis. The external or open conformation
of H55 is observed to have interactions with two propionate groups
in heme, at distances of 3.82 and 2.73 Å, respectively. A relatively
weak hydrogen bonding interaction between H55 and CO, combined with
strong interactions with heme propionate (position 6), is hypothesized
to strengthen the external conformation of H55. Density function theory
(DFT) calculations were conducted to test whether there is a weaker
hydrogen bond interaction between H55 and heme bonded CO or O2. Molecular dynamics simulations were conducted to examine
how the tautomeric forms of H55 affect the dynamic motions of the
distal histidine that govern the switching between open and closed
conformations. The calculations support the modified hypothesis suggesting
a competition between the strength of interactions with heme ligand
and the heme propionates as the factors that determine the conformation
of the distal histidine.
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Affiliation(s)
- Junjie Zhao
- Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695, United States
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9
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Zhao J, Zhao J, Franzen S. The Regulatory Implications of Hydroquinone for the Multifunctional Enzyme Dehaloperoxidase-Hemoglobin from Amphitrite ornata. J Phys Chem B 2013; 117:14615-24. [DOI: 10.1021/jp407663n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Jing Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Junjie Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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10
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Dumarieh R, D'Antonio J, Deliz-Liang A, Smirnova T, Svistunenko DA, Ghiladi RA. Tyrosyl radicals in dehaloperoxidase: how nature deals with evolving an oxygen-binding globin to a biologically relevant peroxidase. J Biol Chem 2013; 288:33470-82. [PMID: 24100039 DOI: 10.1074/jbc.m113.496497] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dehaloperoxidase (DHP) from Amphitrite ornata, having been shown to catalyze the hydrogen peroxide-dependent oxidation of trihalophenols to dihaloquinones, is the first oxygen binding globin that possesses a biologically relevant peroxidase activity. The catalytically competent species in DHP appears to be Compound ES, a reactive intermediate that contains both a ferryl heme and a tyrosyl radical. By simulating the EPR spectra of DHP activated by H2O2, Thompson et al. (Thompson, M. K., Franzen, S., Ghiladi, R. A., Reeder, B. J., and Svistunenko, D. A. (2010) J. Am. Chem. Soc. 132, 17501-17510) proposed that two different radicals, depending on the pH, are formed, one located on either Tyr-34 or Tyr-28 and the other on Tyr-38. To provide additional support for these simulation-based assignments and to deduce the role(s) that tyrosyl radicals play in DHP, stopped-flow UV-visible and rapid-freeze-quench EPR spectroscopic methods were employed to study radical formation in DHP when three tyrosine residues, Tyr-28, Tyr-34, and Tyr-38, were replaced either individually or in combination with phenylalanines. The results indicate that radicals form on all three tyrosines in DHP. Evidence for the formation of DHP Compound I in several tyrosine mutants was obtained. Variants that formed Compound I showed an increase in the catalytic rate for substrate oxidation but also an increase in heme bleaching, suggesting that the tyrosines are necessary for protecting the enzyme from oxidizing itself. This protective role of tyrosines is likely an evolutionary adaptation allowing DHP to avoid self-inflicted damage in the oxidative environment.
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Affiliation(s)
- Rania Dumarieh
- From the Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204 and
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11
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Wang C, Lovelace LL, Sun S, Dawson JH, Lebioda L. Complexes of Dual-Function Hemoglobin/Dehaloperoxidase with Substrate 2,4,6-Trichlorophenol Are Inhibitory and Indicate Binding of Halophenol to Compound I. Biochemistry 2013; 52:6203-10. [DOI: 10.1021/bi400627w] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chunxue Wang
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Leslie L. Lovelace
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Shengfang Sun
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - John H. Dawson
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
- School
of Medicine, University of South Carolina, Columbia, South Carolina 29209, United States
| | - Lukasz Lebioda
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
- Center
for Colon Cancer Research, University of South Carolina, Columbia, South Carolina 29209, United States
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12
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Matsui H, Tadokoro M. Eigen-like hydrated protons traveling with a local distortion through the water nanotube in new molecular porous crystals {[MIII(H2bim)3](TMA)·20H2O}n (M = Co, Rh, Ru). J Chem Phys 2012; 137:144503. [DOI: 10.1063/1.4757974] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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13
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Zhao J, de Serrano V, Dumarieh R, Thompson M, Ghiladi RA, Franzen S. The Role of the Distal Histidine in H2O2 Activation and Heme Protection in both Peroxidase and Globin Functions. J Phys Chem B 2012; 116:12065-77. [DOI: 10.1021/jp300014b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Junjie Zhao
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Rania Dumarieh
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Matt Thompson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Reza A. Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United
States
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14
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Franzen S, Thompson MK, Ghiladi RA. The dehaloperoxidase paradox. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:578-88. [DOI: 10.1016/j.bbapap.2011.12.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 12/20/2011] [Accepted: 12/23/2011] [Indexed: 12/01/2022]
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15
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Study of the electrostatic effects of mutations on the surface of dehaloperoxidase-hemoglobin A. Biochem Biophys Res Commun 2012; 420:733-7. [DOI: 10.1016/j.bbrc.2012.03.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 03/12/2012] [Indexed: 11/17/2022]
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16
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D'Antonio J, Ghiladi RA. Reactivity of deoxy- and oxyferrous dehaloperoxidase B from Amphitrite ornata: identification of compound II and its ferrous-hydroperoxide precursor. Biochemistry 2011; 50:5999-6011. [PMID: 21619067 DOI: 10.1021/bi200311u] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata is a bifunctional enzyme that possesses both hemoglobin and peroxidase activities. The bifunctional nature of DHP as a globin peroxidase appears to be at odds with the traditional starting oxidation state for each individual activity. Namely, reversible oxygen binding is only mediated via a ferrous heme in globins, and peroxidase activity is initiated from ferric centers and to the exclusion of the oxyferrous oxidation state from the peroxidase cycle. Thus, to address what appears to be a paradox, herein we report the details of our investigations into the DHP catalytic cycle when initiated from the deoxy- and oxyferrous states using biochemical assays, stopped-flow UV-visible, and rapid-freeze-quench electron paramagnetic resonance spectroscopies, and anaerobic methods. We demonstrate the formation of Compound II directly from deoxyferrous DHP B upon its reaction with hydrogen peroxide and show that this occurs both in the presence and in the absence of trihalophenol. Prior to the formation of Compound II, we have identified a new species that we have preliminarily attributed to a ferrous-hydroperoxide precursor that undergoes heterolysis to generate the aforementioned ferryl intermediate. Taken together, the results demonstrate that the oxyferrous state in DHP is a peroxidase competent starting species, and an updated catalytic cycle for DHP is proposed in which the ferric oxidation state is not an obligatory starting point for the peroxidase catalytic cycle of dehaloperoxidase. The data presented herein provide a link between the peroxidase and oxygen transport activities, which furthers our understanding of how this bifunctional enzyme is able to unite its two inherent functions in one system.
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Affiliation(s)
- Jennifer D'Antonio
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
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17
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Thompson MK, Franzen S, Davis MF, Oliver RC, Krueger JK. Dehaloperoxidase-hemoglobin from Amphitrite ornata is primarily a monomer in solution. J Phys Chem B 2011; 115:4266-72. [PMID: 21417234 DOI: 10.1021/jp201156r] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The crystal structures of the dehaloperoxidase-hemoglobin from A. ornata (DHP A) each report a crystallographic dimer in the unit cell. Yet, the largest dimer interface observed is 450 Å(2), an area significantly smaller than the typical value of 1200-2000 Å(2) and in contrast to the extensive interface region of other known dimeric hemoglobins. To examine the oligomerization state of DHP A in solution, we used gel permeation by fast protein liquid chromatography and small-angle X-ray scattering (SAXS). Gel permeation experiments demonstrate that DHP A elutes as a monomer (15.5 kDa) and can be separated from green fluorescent protein, which has a molar mass of 27 kDa, near the 31 kDa expected for the DHP A dimer. By SAXS, we found that DHP A is primarily monomeric in solution, but with a detectable level of dimer (~10%), under all conditions studied up to a protein concentration of 3.0 mM. These concentrations are likely 10-100-fold lower than the K(d) for dimer formation. Additionally, there was no significant effect either on the overall conformation of DHP A or its monomer-dimer equilibrium upon addition of the DHP A inhibitor, 4-iodophenol.
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Affiliation(s)
- Matthew K Thompson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
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18
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Thompson MK, Davis MF, de Serrano V, Nicoletti FP, Howes BD, Smulevich G, Franzen S. Internal binding of halogenated phenols in dehaloperoxidase-hemoglobin inhibits peroxidase function. Biophys J 2010; 99:1586-95. [PMID: 20816071 DOI: 10.1016/j.bpj.2010.05.041] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 05/11/2010] [Accepted: 05/17/2010] [Indexed: 10/19/2022] Open
Abstract
Dehaloperoxidase (DHP) from the annelid Amphitrite ornata is a catalytically active hemoglobin-peroxidase that possesses a unique internal binding cavity in the distal pocket above the heme. The previously published crystal structure of DHP shows 4-iodophenol bound internally. This led to the proposal that the internal binding site is the active site for phenol oxidation. However, the native substrate for DHP is 2,4,6-tribromophenol, and all attempts to bind 2,4,6-tribromophenol in the internal site under physiological conditions have failed. Herein, we show that the binding of 4-halophenols in the internal pocket inhibits enzymatic function. Furthermore, we demonstrate that DHP has a unique two-site competitive binding mechanism in which the internal and external binding sites communicate through two conformations of the distal histidine of the enzyme, resulting in nonclassical competitive inhibition. The same distal histidine conformations involved in DHP function regulate oxygen binding and release during transport and storage by hemoglobins and myoglobins. This work provides further support for the hypothesis that DHP possesses an external binding site for substrate oxidation, as is typical for the peroxidase family of enzymes.
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Affiliation(s)
- Matthew K Thompson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA
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19
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Davydov R, Osborne RL, Shanmugam M, Du J, Dawson JH, Hoffman BM. Probing the oxyferrous and catalytically active ferryl states of Amphitrite ornata dehaloperoxidase by cryoreduction and EPR/ENDOR spectroscopy. Detection of compound I. J Am Chem Soc 2010; 132:14995-5004. [PMID: 20925340 PMCID: PMC2978736 DOI: 10.1021/ja1059747] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dehaloperoxidase (DHP) from Amphitrite ornata is a heme protein that can function both as a hemoglobin and as a peroxidase. This report describes the use of 77 K cryoreduction EPR/ENDOR techniques to study both functions of DHP. Cryoreduced oxyferrous [Fe(II)-O(2)] DHP exhibits two EPR signals characteristic of a peroxoferric [Fe(III)-O(2)(2-)] heme species, reflecting the presence of conformational substates in the oxyferrous precursor. (1)H ENDOR spectroscopy of the cryogenerated substates shows that H-bonding interactions between His N(ε)H and heme-bound O(2) in these conformers are similar to those in the β-chain of oxyferrous hemoglobin A (HbA) and oxyferrous myoglobin, respectively. Decay of cryogenerated peroxoferric heme DHP intermediates upon annealing at temperatures above 180 K is accompanied by the appearance of a new paramagnetic species with an axial EPR signal with g(⊥) = 3.75 and g(∥) = 1.96, characteristic of an S = 3/2 spin state. This species is assigned to Compound I (Cpd I), in which a porphyrin π-cation radical is ferromagnetically coupled with an S = 1 ferryl [Fe(IV)═O] ion. This species was also trapped by rapid freeze-quench of the ambient-temperature reaction mixture of ferric [Fe(III)] DHP and H(2)O(2). However, in the latter case Cpd I is reduced very rapidly by a nearby tyrosine to form Cpd ES [(Fe(IV)═O)(porphyrin)/Tyr(•)]. Addition of the substrate analogue 2,4,6-trifluorophenol (F(3)PhOH) suppresses formation of the Cpd I intermediate during annealing of cryoreduced oxyferrous DHP at 190 K but has no effect on the spectroscopic properties of the remaining cryoreduced oxyferrous DHP intermediates and kinetics of their decay. These observations indicate that substrate (i) binds to oxyferrous DHP outside of the distal pocket and (ii) can reduce Cpd I to Cpd II [Fe(IV)═O]. These assumptions are also supported by the observation that F(3)PhOH has only a small effect on the EPR properties of radiolytically cryooxidized and cryoreduced ferrous [Fe(II)] DHP. EPR spectra of cryoreduced ferrous DHP disclose the multiconformational nature of the ferrous DHP precursor. The observation and characterization of Cpds I, II, and ES in the absence and in the presence of F(3)PhOH provides definitive evidence of a mechanism involving consecutive one-electron steps and clarifies the role of all intermediates formed during turnover.
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Affiliation(s)
- Roman Davydov
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Robert L. Osborne
- Department of Chemistry and Biochemistry University of South Carolina, Columbia, South Carolina 29208
| | | | - Jing Du
- Department of Chemistry and Biochemistry University of South Carolina, Columbia, South Carolina 29208
| | - John H. Dawson
- Department of Chemistry and Biochemistry University of South Carolina, Columbia, South Carolina 29208
- School of Medicine University of South Carolina, Columbia, South Carolina 29208
| | - Brian M. Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
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20
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Ma H, Thompson MK, Gaff J, Franzen S. Kinetic Analysis of a Naturally Occurring Bioremediation Enzyme: Dehaloperoxidase-Hemoglobin from Amphitrite ornata. J Phys Chem B 2010; 114:13823-9. [DOI: 10.1021/jp1014516] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Huan Ma
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, and Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Matthew K. Thompson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, and Department of Chemistry, Zhejiang University, Hangzhou, China
| | - John Gaff
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, and Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, and Department of Chemistry, Zhejiang University, Hangzhou, China
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21
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D'Antonio J, D'Antonio EL, Thompson MK, Bowden EF, Franzen S, Smirnova T, Ghiladi RA. Spectroscopic and mechanistic investigations of dehaloperoxidase B from Amphitrite ornata. Biochemistry 2010; 49:6600-16. [PMID: 20545299 DOI: 10.1021/bi100407v] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata is a bifunctional enzyme that possesses both hemoglobin and peroxidase activities. Of the two DHP isoenzymes identified to date, much of the recent focus has been on DHP A, whereas very little is known pertaining to the activity, substrate specificity, mechanism of function, or spectroscopic properties of DHP B. Herein, we report the recombinant expression and purification of DHP B, as well as the details of our investigations into its catalytic cycle using biochemical assays, stopped-flow UV-visible, resonance Raman, and rapid freeze-quench electron paramagnetic resonance spectroscopies, and spectroelectrochemistry. Our experimental design reveals mechanistic insights and kinetic descriptions of the dehaloperoxidase mechanism which have not been previously reported for isoenzyme A. Namely, we demonstrate a novel reaction pathway in which the products of the oxidative dehalogenation of trihalophenols (dihaloquinones) are themselves capable of inducing formation of oxyferrous DHP B, and an updated catalytic cycle for DHP is proposed. We further demonstrate that, unlike the traditional monofunctional peroxidases, the oxyferrous state in DHP is a peroxidase-competent starting species, which suggests that the ferric oxidation state may not be an obligatory starting point for the enzyme. The data presented herein provide a link between the peroxidase and oxygen transport activities which furthers our understanding of how this bifunctional enzyme is able to unite its two inherent functions in one system.
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Affiliation(s)
- Jennifer D'Antonio
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
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22
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de Serrano V, D'Antonio J, Franzen S, Ghiladi RA. Structure of dehaloperoxidase B at 1.58 A resolution and structural characterization of the AB dimer from Amphitrite ornata. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2010; 66:529-38. [PMID: 20445228 PMCID: PMC2865366 DOI: 10.1107/s0907444910004580] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 02/08/2010] [Indexed: 11/10/2022]
Abstract
As members of the globin superfamily, dehaloperoxidase (DHP) isoenzymes A and B from the marine annelid Amphitrite ornata possess hemoglobin function, but they also exhibit a biologically relevant peroxidase activity that is capable of converting 2,4,6-trihalophenols to the corresponding 2,6-dihaloquinones in the presence of hydrogen peroxide. Here, a comprehensive structural study of recombinant DHP B, both by itself and cocrystallized with isoenzyme A, using X-ray diffraction is presented. The structure of DHP B refined to 1.58 A resolution exhibits the same distal histidine (His55) conformational flexibility as that observed in isoenzyme A, as well as additional changes to the distal and proximal hydrogen-bonding networks. Furthermore, preliminary characterization of the DHP AB heterodimer is presented, which exhibits differences in the AB interface that are not observed in the A-only or B-only homodimers. These structural investigations of DHP B provide insights that may relate to the mechanistic details of the H(2)O(2)-dependent oxidative dehalogenation reaction catalyzed by dehaloperoxidase, present a clearer description of the function of specific residues in DHP at the molecular level and lead to a better understanding of the paradigms of globin structure-function relationships.
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23
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Davis MF, Bobay BG, Franzen S. Determination of separate inhibitor and substrate binding sites in the dehaloperoxidase-hemoglobin from Amphitrite ornata. Biochemistry 2010; 49:1199-206. [PMID: 20067301 DOI: 10.1021/bi9018576] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dehaloperoxidase-hemoglobin (DHP A) is a dual function protein found in the terrebellid polychaete Amphitrite ornata. A. ornata is an annelid, which inhabits estuary mudflats with other polychaetes that secrete a range of toxic brominated phenols. DHP A is capable of binding and oxidatively dehalogenating some of these compounds. DHP A possesses the ability to bind halophenols in a distinct, internal distal binding pocket. Since its discovery, the distal binding pocket has been reported as the sole binding location for halophenols; however, data herein suggest a distinction between inhibitor (monohalogenated phenol) and substrate (trihalogenated phenol) binding locations. Backbone (13)Calpha, (13)Cbeta, carbonyl (13)C, amide (1)H, and amide (15)N resonance assignments have been made, and various halophenols were titrated into the protein. (1)H-(15)N HSQC experiments were collected at stoichiometric intervals during each titration, and binding locations specific for mono- and trihalogenated phenols have been identified. Titration of monohalogenated phenol induced primary changes around the distal binding pocket, while introduction of trihalogenated phenols created alterations of the distal histidine and the local area surrounding W120, a structural region that corresponds to a possible dimer interface region recently observed in X-ray crystal structures of DHP A.
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Affiliation(s)
- Michael F Davis
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27606, USA
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24
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Nicoletti FP, Thompson MK, Howes BD, Franzen S, Smulevich G. New Insights into the Role of Distal Histidine Flexibility in Ligand Stabilization of Dehaloperoxidase−Hemoglobin from Amphitrite ornata. Biochemistry 2010; 49:1903-12. [DOI: 10.1021/bi9020567] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Francesco P. Nicoletti
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy
| | - Matthew K. Thompson
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695
| | - Barry D. Howes
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695
| | - Giulietta Smulevich
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy
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25
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Osborne RL, Coggins MK, Raner GM, Walla M, Dawson JH. The mechanism of oxidative halophenol dehalogenation by Amphitrite ornata dehaloperoxidase is initiated by H2O2 binding and involves two consecutive one-electron steps: role of ferryl intermediates. Biochemistry 2009; 48:4231-8. [PMID: 19371065 DOI: 10.1021/bi900367e] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The enzymatic globin, dehaloperoxidase (DHP), from the terebellid polychaete Amphitrite ornata is designed to catalyze the oxidative dehalogenation of halophenol substrates. In this study, the ability of DHP to catalyze this reaction by a mechanism involving two consecutive one-electron steps via the normal order of addition of the oxidant cosubstrate (H(2)O(2)) before organic substrate [2,4,6-trichlorophenol (TCP)] is demonstrated. Specifically, 1 equiv of H(2)O(2) will fully convert 1 equiv of TCP to 2,6-dichloro-1,4-benzoquinone, implicating the role of multiple ferryl [Fe(IV)O] species. A significant amount of heterolytic cleavage of the O-O bond of cumene hydroperoxide, consistent with transient formation of a Compound I [Fe(IV)O/porphyrin pi-cation radical] species, is observed upon its reaction with ferric DHP. In addition, a more stable high-valent Fe(IV)O-containing DHP intermediate [Compound II (Cpd II) or Compound ES] is characterized by UV-visible absorption and magnetic circular dichroism spectroscopy. Spectral similarities are seen between this intermediate and horse heart myoglobin Cpd II. It is also shown in single-turnover experiments that the DHP Fe(IV)O intermediate is an active oxidant in halophenol oxidative dehalogenation. Furthermore, reaction of DHP with 4-chlorophenol leads to a dimeric product. The results presented herein are consistent with a normal peroxidase order of addition of the oxidant cosubstrate (H(2)O(2)) followed by organic substrate (TCP) and indicate that the enzymatic mechanism of DHP-catalyzed oxidative halophenol dehalogenation involves two consecutive one-electron steps with a dissociable radical intermediate.
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Affiliation(s)
- Robert L Osborne
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA
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26
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Feducia J, Dumarieh R, Gilvey LBG, Smirnova T, Franzen S, Ghiladi RA. Characterization of dehaloperoxidase compound ES and its reactivity with trihalophenols. Biochemistry 2009; 48:995-1005. [PMID: 19187035 DOI: 10.1021/bi801916j] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dehaloperoxidase (DHP), the oxygen transport hemoglobin from the terebellid polychaete Amphitrite ornata, is the first globin identified to possess a biologically relevant peroxidase activity. DHP has been shown to oxidize trihalophenols to dihaloquinones in a dehalogenation reaction that uses hydrogen peroxide as a substrate. Herein, we demonstrate that the first detectable intermediate following the addition of hydrogen peroxide to ferric DHP contains both a ferryl heme and a tyrosyl radical, analogous to Compound ES of cytochrome c peroxidase. Furthermore, we provide a detailed kinetic description for the reaction of preformed DHP Compound ES with the substrate 2,4,6-trichlorophenol and demonstrate the catalytic competency of this intermediate in generating the product 2,4-dichloroquinone. Using rapid-freeze-quench electron paramagnetic resonance spectroscopy, we detected a g approximately 2.0058 signal confirming the presence of a protein radical in DHP Compound ES. In the absence of substrate, DHP Compound ES evolves to a new species, Compound RH, which is functionally unique to dehaloperoxidase. We propose that this intermediate plays a protective role against heme bleaching. While unreactive toward further oxidation, Compound RH can be reduced and subsequently bind dioxygen, generating oxyferrous DHP, which may represent the catalytic link between peroxidase and oxygen transport activities in this bifunctional protein.
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Affiliation(s)
- Jeremiah Feducia
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
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27
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Davis MF, Gracz H, Vendeix FAP, de Serrano V, Somasundaram A, Decatur SM, Franzen S. Different Modes of Binding of Mono-, Di-, and Trihalogenated Phenols to the Hemoglobin Dehaloperoxidase from Amphitrite ornata. Biochemistry 2009; 48:2164-72. [DOI: 10.1021/bi801568s] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael F. Davis
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27606, Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27606, and Chemistry Department, Oberlin College, Oberlin, Ohio 44074
| | - Hanna Gracz
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27606, Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27606, and Chemistry Department, Oberlin College, Oberlin, Ohio 44074
| | - Franck A. P. Vendeix
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27606, Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27606, and Chemistry Department, Oberlin College, Oberlin, Ohio 44074
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27606, Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27606, and Chemistry Department, Oberlin College, Oberlin, Ohio 44074
| | - Aswin Somasundaram
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27606, Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27606, and Chemistry Department, Oberlin College, Oberlin, Ohio 44074
| | - Sean M. Decatur
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27606, Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27606, and Chemistry Department, Oberlin College, Oberlin, Ohio 44074
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27606, Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27606, and Chemistry Department, Oberlin College, Oberlin, Ohio 44074
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28
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Nienhaus K, Nickel E, Davis MF, Franzen S, Nienhaus GU. Determinants of Substrate Internalization in the Distal Pocket of Dehaloperoxidase Hemoglobin of Amphitrite ornata. Biochemistry 2008; 47:12985-94. [DOI: 10.1021/bi801564r] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Karin Nienhaus
- Institute of Biophysics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and Department of Physics, University of Illinois at Urbana−Champaign, 1110 West Green Street, Urbana, Illinois 61801
| | - Elena Nickel
- Institute of Biophysics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and Department of Physics, University of Illinois at Urbana−Champaign, 1110 West Green Street, Urbana, Illinois 61801
| | - Michael F. Davis
- Institute of Biophysics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and Department of Physics, University of Illinois at Urbana−Champaign, 1110 West Green Street, Urbana, Illinois 61801
| | - Stefan Franzen
- Institute of Biophysics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and Department of Physics, University of Illinois at Urbana−Champaign, 1110 West Green Street, Urbana, Illinois 61801
| | - G. Ulrich Nienhaus
- Institute of Biophysics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, and Department of Physics, University of Illinois at Urbana−Champaign, 1110 West Green Street, Urbana, Illinois 61801
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29
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García-Rubio I, Fittipaldi M, Trandafir F, Van Doorslaer S. A Multifrequency HYSCORE Study of Weakly Coupled Nuclei in Frozen Solutions of High-Spin Aquometmyoglobin. Inorg Chem 2008; 47:11294-304. [DOI: 10.1021/ic8016886] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Inés García-Rubio
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zürich, Switzerland, and Department of Physics, University of Antwerp, B-2610 Wilrijk-Antwerp, Belgium
| | - Maria Fittipaldi
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zürich, Switzerland, and Department of Physics, University of Antwerp, B-2610 Wilrijk-Antwerp, Belgium
| | - Florin Trandafir
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zürich, Switzerland, and Department of Physics, University of Antwerp, B-2610 Wilrijk-Antwerp, Belgium
| | - Sabine Van Doorslaer
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zürich, Switzerland, and Department of Physics, University of Antwerp, B-2610 Wilrijk-Antwerp, Belgium
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30
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Mikšovská J, Horsa S, Davis MF, Franzen S. Conformational Dynamics Associated with Photodissociation of CO from Dehaloperoxidase Studied Using Photoacoustic Calorimetry. Biochemistry 2008; 47:11510-7. [DOI: 10.1021/bi8012033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jaroslava Mikšovská
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, and Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Simona Horsa
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, and Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Michael F. Davis
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, and Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Stefan Franzen
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, and Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
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