@article{dumarieh_d'antonio_deliz-liang_smirnova_svistunenko_ghiladi_2013, title={Tyrosyl radicals in dehaloperoxidase how nature deals with evolving an oxygen-binding globin to a biologically relevant peroxidase}, volume={288}, number={46}, journal={Journal of Biological Chemistry}, author={Dumarieh, R. and D'Antonio, J. and Deliz-Liang, A. and Smirnova, T. and Svistunenko, D. A. and Ghiladi, R. A.}, year={2013}, pages={33470–33482} } @article{edward l. d'antonio_bowden_franzen_2012, title={Thin-layer spectroelectrochemistry of the Fe(III)/Fe(II) redox reaction of dehaloperoxidase-hemoglobin}, volume={668}, ISSN={["1873-2569"]}, DOI={10.1016/j.jelechem.2011.12.015}, abstractNote={Dehaloperoxidase-hemoglobin (DHP A; isoenzyme A) is a globin from the annelid Amphitrite ornata that displays enhanced peroxidase activity compared to other myoglobins and hemoglobins. In this study, anaerobic thin-layer spectroelectrochemistry was used to measure formal reduction potentials (E°′) for the Fe(III)/Fe(II) redox couple of DHP A from pH 5.0 to pH 7.0. The value of E°′ determined at pH 7.0 (100 mM potassium phosphate buffer under ambient temperature), +0.202 ± 0.006 V vs SHE, gives DHP A the most positive Fe(III)/Fe(II) reduction potential among known intracellular globins (approximately 150 mV and 50 mV higher than typical myoglobins and hemoglobins, respectively). This finding is particularly distinctive in light of DHP A's enhanced peroxidase activity, a function that is commonly carried out from the Fe(III) state, which is favored by more negative reduction potentials. For example, horseradish peroxidase has a formal potential that falls 0.47 V negative of the DHP A value. Using available crystal structures, two major energetic factors involving the distal histidine (H55) have been identified that appear to account for the unusually positive DHP A reduction potential. First, H55, which is positioned ∼1 Å further away from the heme iron than distal histidines in hemoglobin and myoglobin, displays a diminished capacity to serve as the hydrogen bond acceptor for a ligated water molecule, resulting in destabilization of the Fe(III) state relative to a common globin. The more distant positioning of H55 from the heme iron also imparts to it a conformational flexibility, which is linked to the electron transfer reaction. In its internal (closed) conformation, H55 hydrogen bonds with and stabilizes an iron-ligated H2O molecule, whereas in its external (open) conformation, H55 hydrogen bonds to a heme propionate resulting in a 5-coordinate heme iron. A thermodynamic cycle that links the conformational change to electron transfer is shown to be consistent with a positive shift in reduction potential if the open conformation is differentially favored by the Fe(II) state, a proposal that is supported by the available crystallographic data.}, journal={JOURNAL OF ELECTROANALYTICAL CHEMISTRY}, author={Edward L. D'Antonio and Bowden, Edmond F. and Franzen, Stefan}, year={2012}, month={Mar}, pages={37–43} } @article{d'antonio_chen_turner_santiago-capeles_bowden_2013, title={Voltammetry of dehaloperoxidase on self-assembled monolayers: Reversible adsorptive immobilization of a globin}, volume={26}, ISSN={1388-2481}, url={http://dx.doi.org/10.1016/j.elecom.2012.10.011}, DOI={10.1016/j.elecom.2012.10.011}, abstractNote={Abstract Dehaloperoxidase (DHP), a monomeric hemoglobin, was adsorptively immobilized under low ionic strength conditions on binary self-assembled monolayers composed of OH- and COOH-terminated alkylthiols. Voltammetry of its Fe(III)/Fe(II) reactions revealed adsorbed DHP to be electroactive and native under both anaerobic and aerobic conditions. The chemically reversible nature of the adsorptive immobilization was established from voltammetric desorption/re-adsorption experiments. Cyclic voltammetric determination of electroactive surface concentration uncovered an unusual inverse scan rate dependence that was rationalized by means of Hoffman's dynamic docking electron transfer model [Z.-X. Liang et al., J. Am. Chem. Soc. 126 (2004) 2785]. This result represents the first evidence for dynamic docking control of protein electron transfer in an electrochemical setting.}, journal={Electrochemistry Communications}, publisher={Elsevier BV}, author={D'Antonio, Edward L. and Chen, Thomas K. and Turner, Abigail H. and Santiago-Capeles, Lisandra and Bowden, Edmond F.}, year={2013}, month={Jan}, pages={67–70} } @article{d’antonio_d’antonio_de serrano_gracz_thompson_ghiladi_bowden_franzen_2011, title={Functional Consequences of the Creation of an Asp-His-Fe Triad in a 3/3 Globin}, volume={50}, ISSN={0006-2960 1520-4995}, url={http://dx.doi.org/10.1021/bi201368u}, DOI={10.1021/bi201368u}, abstractNote={The proximal side of dehaloperoxidase-hemoglobin A (DHP A) from Amphitrite ornata has been modified via site-directed mutagenesis of methionine 86 into aspartate (M86D) to introduce an Asp-His-Fe triad charge relay. X-ray crystallographic structure determination of the metcyano forms of M86D [Protein Data Bank (PDB) entry 3MYN ] and M86E (PDB entry 3MYM ) mutants reveal the structural origins of a stable catalytic triad in DHP A. A decrease in the rate of H(2)O(2) activation as well as a lowered reduction potential versus that of the wild-type enzyme was observed in M86D. One possible explanation for the significantly lower activity is an increased affinity for the distal histidine in binding to the heme Fe to form a bis-histidine adduct. Resonance Raman spectroscopy demonstrates a pH-dependent ligation by the distal histidine in M86D, which is indicative of an increased trans effect. At pH 5.0, the heme Fe is five-coordinate, and this structure resembles the wild-type DHP A resting state. However, at pH 7.0, the distal histidine appears to form a six-coordinate ferric bis-histidine (hemichrome) adduct. These observations can be explained by the effect of the increased positive charge on the heme Fe on the formation of a six-coordinate low-spin adduct, which inhibits the ligation and activation of H(2)O(2) as required for peroxidase activity. The results suggest that the proximal charge relay in peroxidases regulate the redox potential of the heme Fe but that the trans effect is a carefully balanced property that can both activate H(2)O(2) and attract ligation by the distal histidine. To understand the balance of forces that modulate peroxidase reactivity, we studied three M86 mutants, M86A, M86D, and M86E, by spectroelectrochemistry and nuclear magnetic resonance spectroscopy of (13)C- and (15)N-labeled cyanide adducts as probes of the redox potential and of the trans effect in the heme Fe, both of which can be correlated with the proximity of negative charge to the N(δ) hydrogen of the proximal histidine, consistent with an Asp-His-Fe charge relay observed in heme peroxidases.}, number={44}, journal={Biochemistry}, publisher={American Chemical Society (ACS)}, author={D’Antonio, Edward L. and D’Antonio, Jennifer and de Serrano, Vesna and Gracz, Hanna and Thompson, Matthew K. and Ghiladi, Reza A. and Bowden, Edmond F. and Franzen, Stefan}, year={2011}, month={Nov}, pages={9664–9680} } @article{d’antonio_d’antonio_thompson_bowden_franzen_smirnova_ghiladi_2010, title={Spectroscopic and Mechanistic Investigations of Dehaloperoxidase B fromAmphitrite ornata}, volume={49}, ISSN={0006-2960 1520-4995}, url={http://dx.doi.org/10.1021/bi100407v}, DOI={10.1021/bi100407v}, abstractNote={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.}, number={31}, journal={Biochemistry}, publisher={American Chemical Society (ACS)}, author={D’Antonio, Jennifer and D’Antonio, Edward L. and Thompson, Matthew K. and Bowden, Edmond F. and Franzen, Stefan and Smirnova, Tatyana and Ghiladi, Reza A.}, year={2010}, month={Aug}, pages={6600–6616} } @article{serrano_davis_gaff_zhang_chen_d'antonio_bowden_rose_franzen_2010, title={X-ray structure of the metcyano form of dehaloperoxidase from Amphitrite ornata: Evidence for photoreductive dissociation of the iron-cyanide bond}, volume={66}, journal={Acta Crystallographica. Section D, Biological Crystallography}, author={Serrano, V. S. and Davis, M. F. and Gaff, J. F. and Zhang, Q. and Chen, Z. and D'Antonio, E. L. and Bowden, E. F. and Rose, R. and Franzen, S.}, year={2010}, pages={770–782} }