1
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Freindorf M, Antonio JJ, Kraka E. Iron-histidine bonding in bishistidyl hemoproteins-A local vibrational mode study. J Comput Chem 2024; 45:574-588. [PMID: 38041830 DOI: 10.1002/jcc.27267] [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: 08/12/2023] [Revised: 11/09/2023] [Accepted: 11/11/2023] [Indexed: 12/04/2023]
Abstract
We investigated the intrinsic strength of distal and proximal FeN bonds for both ferric and ferrous oxidation states of bishistidyl hemoproteins from bacteria, animals, human, and plants, including two cytoglobins, ten hemoglobins, two myoglobins, six neuroglobins, and six phytoglobins. As a qualified measure of bond strength, we used local vibrational force constants ka (FeN) based on local mode theory developed in our group. All calculations were performed with a hybrid QM/MM ansatz. Starting geometries were taken from available x-ray structures. ka (FeN) values were correlated with FeN bond lengths and covalent bond character. We also investigated the stiffness of the axial NFeN bond angle. Our results highlight that protein effects are sensitively reflected in ka (FeN), allowing one to compare trends in diverse protein groups. Moreover, ka (NFeN) is a perfect tool to monitor changes in the axial heme framework caused by different protein environments as well as different Fe oxidation states.
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Affiliation(s)
- Marek Freindorf
- Chemistry Department, Southern Methodist University, Dallas, Texas, USA
| | - Juliana J Antonio
- Chemistry Department, Southern Methodist University, Dallas, Texas, USA
| | - Elfi Kraka
- Chemistry Department, Southern Methodist University, Dallas, Texas, USA
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2
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Zhang L, Brown MC, Mutter AC, Greenland KN, Cooley JW, Koder RL. Protein dynamics govern the oxyferrous state lifetime of an artificial oxygen transport protein. Biophys J 2023; 122:4440-4450. [PMID: 37865818 PMCID: PMC10698322 DOI: 10.1016/j.bpj.2023.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/26/2023] [Accepted: 10/19/2023] [Indexed: 10/23/2023] Open
Abstract
It has long been known that the alteration of protein side chains that occlude or expose the heme cofactor to water can greatly affect the stability of the oxyferrous heme state. Here, we demonstrate that the rate of dynamically driven water penetration into the core of an artificial oxygen transport protein also correlates with oxyferrous state lifetime by reducing global dynamics, without altering the structure of the active site, via the simple linking of the two monomers in a homodimeric artificial oxygen transport protein using a glycine-rich loop. The tethering of these two helices does not significantly affect the active site structure, pentacoordinate heme-binding affinity, reduction potential, or gaseous ligand affinity. It does, however, significantly reduce the hydration of the protein core, as demonstrated by resonance Raman spectroscopy, backbone amide hydrogen exchange, and pKa shifts in buried histidine side chains. This further destabilizes the charge-buried entatic state and nearly triples the oxyferrous state lifetime. These data are the first direct evidence that dynamically driven water penetration is a rate-limiting step in the oxidation of these complexes. It furthermore demonstrates that structural rigidity that limits water penetration is a critical design feature in metalloenzyme construction and provides an explanation for both the failures and successes of earlier attempts to create oxygen-binding proteins.
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Affiliation(s)
- Lei Zhang
- Department of Physics, The City College of New York, New York, New York
| | - Mia C Brown
- Department of Chemistry, University of Missouri, Columbia, Missouri
| | - Andrew C Mutter
- Department of Biochemistry, The City College of New York, New York, New York
| | - Kelly N Greenland
- Department of Physics, The City College of New York, New York, New York
| | - Jason W Cooley
- Department of Chemistry, University of Missouri, Columbia, Missouri
| | - Ronald L Koder
- Department of Physics, The City College of New York, New York, New York; Graduate Programs of Physics, Biology, Chemistry and Biochemistry, The Graduate Center of CUNY, New York, New York.
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3
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Redox potential determination of the Hell’s gate globin I protein facing multiple exogenous ligands. Microchem J 2022. [DOI: 10.1016/j.microc.2022.108027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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4
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Becana M, Yruela I, Sarath G, Catalán P, Hargrove MS. Plant hemoglobins: a journey from unicellular green algae to vascular plants. THE NEW PHYTOLOGIST 2020; 227:1618-1635. [PMID: 31960995 DOI: 10.1111/nph.16444] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 12/24/2019] [Indexed: 05/17/2023]
Abstract
Globins (Glbs) are widely distributed in archaea, bacteria and eukaryotes. They can be classified into proteins with 2/2 or 3/3 α-helical folding around the heme cavity. Both types of Glbs occur in green algae, bryophytes and vascular plants. The Glbs of angiosperms have been more intensively studied, and several protein structures have been solved. They can be hexacoordinate or pentacoordinate, depending on whether a histidine is coordinating or not at the sixth position of the iron atom. The 3/3 Glbs of class 1 and the 2/2 Glbs (also called class 3 in plants) are present in all angiosperms, whereas the 3/3 Glbs of class 2 have been only found in early angiosperms and eudicots. The three Glb classes are expected to play different roles. Class 1 Glbs are involved in hypoxia responses and modulate NO concentration, which may explain their roles in plant morphogenesis, hormone signaling, cell fate determination, nutrient deficiency, nitrogen metabolism and plant-microorganism symbioses. Symbiotic Glbs derive from class 1 or class 2 Glbs and transport O2 in nodules. The physiological roles of class 2 and class 3 Glbs are poorly defined but could involve O2 and NO transport and/or metabolism, respectively. More research is warranted on these intriguing proteins to determine their non-redundant functions.
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Affiliation(s)
- Manuel Becana
- Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas (CSIC), Apartado 13034, 50080, Zaragoza, Spain
| | - Inmaculada Yruela
- Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas (CSIC), Apartado 13034, 50080, Zaragoza, Spain
- Group of Biochemistry, Biophysics and Computational Biology (BIFI-Unizar) Joint Unit to CSIC, Edificio I+D Campus Río Ebro, 50018, Zaragoza, Spain
| | - Gautam Sarath
- Wheat, Sorghum, and Forage Research Unit, USDA-ARS, East Campus, University of Nebraska-Lincoln, Lincoln, NE, 86583, USA
| | - Pilar Catalán
- Group of Biochemistry, Biophysics and Computational Biology (BIFI-Unizar) Joint Unit to CSIC, Edificio I+D Campus Río Ebro, 50018, Zaragoza, Spain
- Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, 22071, Huesca, Spain
| | - Mark S Hargrove
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
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5
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Ascenzi P, De Simone G, Ciaccio C, Santucci R, Coletta M. Hydroxylamine-induced oxidation of ferrous CO-bound carboxymethylated-cytochrome c. J PORPHYR PHTHALOCYA 2018. [DOI: 10.1142/s1088424618501055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The hexa-coordinated metal center of horse heart cyt[Formula: see text] (cyt[Formula: see text] is at the root of its low reactivity. In contrast, carboxymethylated cyt[Formula: see text] (CM-cyt[Formula: see text] displays myoglobin-like properties. Herein, kinetics of CO binding to ferrous CM-cyt[Formula: see text] (CM-cyt[Formula: see text](II)) and of the irreversible oxidation of ferrous carbonylated CM-cyt[Formula: see text] (CM-cyt[Formula: see text](II)-CO) by hydroxylamine (HA), at pH 5.8 and 20.0 [Formula: see text]C, are reported. HA irreversibly oxidizes CM-cyt[Formula: see text](II)-CO with the 1:2 stoichiometry leading to the formation of the ferric species (CM-cyt[Formula: see text](III)) without the observation of intermediates. Present data indicate that: (i) the rate of CO dissociation from CM-cyt[Formula: see text](II)-CO represents the rate-limiting step of HA-mediated oxidation of the carbonylated metal center, (ii) the fast oxidation of CM-cyt[Formula: see text](II)-CO from HA reflects the penta-coordination of the transient CM-cyt[Formula: see text](II) species, (iii) the HA-catalyzed conversion of CM-cyt[Formula: see text](II)-CO to CM-cyt[Formula: see text](III) could proceed via the geminate mechanism, (iv) values of the second-order rate constants for the carbonylation and the HA-mediated oxidation of ferrous heme-proteins are linearly correlated reflecting the penta- or hexa-coordination of the metal center, the free energy for the in-plane positioning of the heme-Fe atom in the unliganded species, and the arrangement of the distal portion of the heme pocket that affects ligand and/or electron transfer.
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Affiliation(s)
- Paolo Ascenzi
- Interdepartmental Laboratory for Electron Microscopy, Roma Tre University, I-00146 Roma, Italy
| | | | - Chiara Ciaccio
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, I-00133 Roma, Italy
- Interuniversity Consortium for the Research on Chemistry of Metals in Biological Systems, I-70126 Bari, Italy
| | - Roberto Santucci
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, I-00133 Roma, Italy
| | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, I-00133 Roma, Italy
- Interuniversity Consortium for the Research on Chemistry of Metals in Biological Systems, I-70126 Bari, Italy
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6
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Nye DB, Lecomte JTJ. Replacement of the Distal Histidine Reveals a Noncanonical Heme Binding Site in a 2-on-2 Hemoglobin. Biochemistry 2018; 57:5785-5796. [PMID: 30213188 PMCID: PMC6217817 DOI: 10.1021/acs.biochem.8b00752] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heme ligation in hemoglobin is typically assumed by the "proximal" histidine. Hydrophobic contacts, ionic interactions, and the ligation bond secure the heme between two α-helices denoted E and F. Across the hemoglobin superfamily, several proteins also use a "distal" histidine, making the native state a bis-histidine complex. The group 1 truncated hemoglobin from Synechocystis sp. PCC 6803, GlbN, is one such bis-histidine protein. Ferric GlbN, in which the distal histidine (His46 or E10) has been replaced with a leucine, though expected to bind a water molecule and yield a high-spin iron complex at neutral pH, has low-spin spectral properties. Here, we applied nuclear magnetic resonance and electronic absorption spectroscopic methods to GlbN modified with heme and amino acid replacements to identify the distal ligand in H46L GlbN. We found that His117, a residue located in the C-terminal portion of the protein and on the proximal side of the heme, is responsible for the formation of an alternative bis-histidine complex. Simultaneous coordination by His70 and His117 situates the heme in a binding site different from the canonical site. This new holoprotein form is achieved with only local conformational changes. Heme affinity in the alternative site is weaker than in the normal site, likely because of strained coordination and a reduced number of specific heme-protein interactions. The observation of an unconventional heme binding site has important implications for the interpretation of mutagenesis results and globin homology modeling.
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Affiliation(s)
- Dillon B. Nye
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, United States
| | - Juliette T. J. Lecomte
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, United States
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7
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The nitrite reductase activity of ferrous human hemoglobin:haptoglobin 1-1 and 2-2 complexes. J Inorg Biochem 2018; 187:116-122. [DOI: 10.1016/j.jinorgbio.2018.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/14/2018] [Accepted: 07/17/2018] [Indexed: 12/16/2022]
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8
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Mot AC, Puscas C, Miclea P, Naumova-Letia G, Dorneanu S, Podar D, Dissmeyer N, Silaghi-Dumitrescu R. Redox control and autoxidation of class 1, 2 and 3 phytoglobins from Arabidopsis thaliana. Sci Rep 2018; 8:13714. [PMID: 30209406 PMCID: PMC6135765 DOI: 10.1038/s41598-018-31922-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/28/2018] [Indexed: 12/29/2022] Open
Abstract
Despite a recent increase in interest towards phytoglobins and their importance in plants, much is still unknown regarding their biochemical/biophysical properties and physiological roles. The present study presents data on three recombinant Arabidopsis phytoglobins in terms of their UV-vis and Raman spectroscopic characteristics, redox state control, redox potentials and autoxidation rates. The latter are strongly influenced by pH for all three hemoglobins - (with a fundamental involvement of the distal histidine), as well as by added anion concentrations - suggesting either a process dominated by nucleophilic displacement of superoxide for AtHb2 or an inhibitory effect for AtHb1 and AtHb3. Reducing agents, such as ascorbate and glutathione, are found to either enhance- (presumably via direct electron transfer or via allosteric regulation) or prevent autoxidation. HbFe3+ reduction was possible in the presence of high (presumably not physiologically relevant) concentrations of NADH, glutathione and ascorbate, with differing behaviors for the three globins. The iron coordination sphere is found to affect the autoxidation, redox state interconversion and redox potentials in these three phytoglobins.
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Affiliation(s)
- Augustin C Mot
- Research Center for Advanced Chemical Analysis, Instrumentation and Chemometrics, Babes-Bolyai University, 11 Arany Janos Street, RO-400028, Cluj-Napoca, Romania.
- Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, 1 Mihail Kogalniceanu Street, RO-400084, Cluj-Napoca, Romania.
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle (Saale), Germany.
| | - Cristina Puscas
- Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, 1 Mihail Kogalniceanu Street, RO-400084, Cluj-Napoca, Romania
| | - Patricia Miclea
- Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, 1 Mihail Kogalniceanu Street, RO-400084, Cluj-Napoca, Romania
| | - Galaba Naumova-Letia
- Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, 1 Mihail Kogalniceanu Street, RO-400084, Cluj-Napoca, Romania
| | - Sorin Dorneanu
- Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, 1 Mihail Kogalniceanu Street, RO-400084, Cluj-Napoca, Romania
| | - Dorina Podar
- Faculty of Biology and Geology, Babes-Bolyai University, 1 Mihail Kogalniceanu Street, RO-400084, Cluj-Napoca, Romania
| | - Nico Dissmeyer
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle (Saale), Germany
| | - Radu Silaghi-Dumitrescu
- Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, 1 Mihail Kogalniceanu Street, RO-400084, Cluj-Napoca, Romania.
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9
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Bellei M, Bortolotti CA, Di Rocco G, Borsari M, Lancellotti L, Ranieri A, Sola M, Battistuzzi G. The influence of the Cys46/Cys55 disulfide bond on the redox and spectroscopic properties of human neuroglobin. J Inorg Biochem 2018; 178:70-86. [DOI: 10.1016/j.jinorgbio.2017.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/21/2017] [Accepted: 10/09/2017] [Indexed: 12/21/2022]
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10
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Gell DA. Structure and function of haemoglobins. Blood Cells Mol Dis 2017; 70:13-42. [PMID: 29126700 DOI: 10.1016/j.bcmd.2017.10.006] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 10/29/2017] [Accepted: 10/30/2017] [Indexed: 12/18/2022]
Abstract
Haemoglobin (Hb) is widely known as the iron-containing protein in blood that is essential for O2 transport in mammals. Less widely recognised is that erythrocyte Hb belongs to a large family of Hb proteins with members distributed across all three domains of life-bacteria, archaea and eukaryotes. This review, aimed chiefly at researchers new to the field, attempts a broad overview of the diversity, and common features, in Hb structure and function. Topics include structural and functional classification of Hbs; principles of O2 binding affinity and selectivity between O2/NO/CO and other small ligands; hexacoordinate (containing bis-imidazole coordinated haem) Hbs; bacterial truncated Hbs; flavohaemoglobins; enzymatic reactions of Hbs with bioactive gases, particularly NO, and protection from nitrosative stress; and, sensor Hbs. A final section sketches the evolution of work on the structural basis for allosteric O2 binding by mammalian RBC Hb, including the development of newer kinetic models. Where possible, reference to historical works is included, in order to provide context for current advances in Hb research.
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Affiliation(s)
- David A Gell
- School of Medicine, University of Tasmania, TAS 7000, Australia.
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11
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Zanetti Polzi L, Battistuzzi G, Borsari M, Pignataro M, Paltrinieri L, Daidone I, Bortolotti CA. Computational investigation of the electron transfer complex between neuroglobin and cytochrome c. Supramol Chem 2017. [DOI: 10.1080/10610278.2017.1377342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Laura Zanetti Polzi
- Department of Physical and Chemical Sciences, University of L’Aquila, L’Aquila, Italy
| | - Gianantonio Battistuzzi
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Marco Borsari
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Marcello Pignataro
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Licia Paltrinieri
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Isabella Daidone
- Department of Physical and Chemical Sciences, University of L’Aquila, L’Aquila, Italy
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12
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Cuypers B, Vermeylen S, Hammerschmid D, Trashin S, Rahemi V, Konijnenberg A, De Schutter A, Cheng CHC, Giordano D, Verde C, De Wael K, Sobott F, Dewilde S, Van Doorslaer S. Antarctic fish versus human cytoglobins - The same but yet so different. J Inorg Biochem 2017; 173:66-78. [PMID: 28501743 DOI: 10.1016/j.jinorgbio.2017.04.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 03/23/2017] [Accepted: 04/26/2017] [Indexed: 10/19/2022]
Abstract
The cytoglobins of the Antarctic fish Chaenocephalus aceratus and Dissostichus mawsoni have many features in common with human cytoglobin. These cytoglobins are heme proteins in which the ferric and ferrous forms have a characteristic hexacoordination of the heme iron, i.e. axial ligation of two endogenous histidine residues, as confirmed by electron paramagnetic resonance, resonance Raman and optical absorption spectroscopy. The combined spectroscopic analysis revealed only small variations in the heme-pocket structure, in line with the small variations observed for the redox potential. Nevertheless, some striking differences were also discovered. Resonance Raman spectroscopy showed that the stabilization of an exogenous heme ligand, such as CO, occurs differently in human cytoglobin in comparison with Antarctic fish cytoglobins. Furthermore, while it has been extensively reported that human cytoglobin is essentially monomeric and can form an intramolecular disulfide bridge that can influence the ligand binding kinetics, 3D modeling of the Antarctic fish cytoglobins indicates that the cysteine residues are too far apart to form such an intramolecular bridge. Moreover, gel filtration and mass spectrometry reveal the occurrence of non-covalent multimers (up to pentamers) in the Antarctic fish cytoglobins that are formed at low concentrations. Stabilization of these oligomers by disulfide-bridge formation is possible, but not essential. If intermolecular disulfide bridges are formed, they influence the heme-pocket structure, as is shown by EPR measurements.
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Affiliation(s)
- Bert Cuypers
- BIMEF Laboratory, Department of Physics, University of Antwerp, Belgium
| | - Stijn Vermeylen
- PPES Laboratory, Department of Biomedical Sciences, University of Antwerp, Belgium
| | - Dietmar Hammerschmid
- PPES Laboratory, Department of Biomedical Sciences, University of Antwerp, Belgium; BAMS Laboratory, Department of Chemistry, University of Antwerp, Belgium
| | - Stanislav Trashin
- AXES Laboratory, Department of Chemistry, University of Antwerp, Belgium
| | - Vanoushe Rahemi
- AXES Laboratory, Department of Chemistry, University of Antwerp, Belgium
| | | | - Amy De Schutter
- BIMEF Laboratory, Department of Physics, University of Antwerp, Belgium
| | | | - Daniela Giordano
- Institute of Biosciences and BioResources, CNR, Naples, Italy; Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Cinzia Verde
- Institute of Biosciences and BioResources, CNR, Naples, Italy; Department of Biology, University Roma 3, Rome, Italy; Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Karolien De Wael
- AXES Laboratory, Department of Chemistry, University of Antwerp, Belgium
| | - Frank Sobott
- BAMS Laboratory, Department of Chemistry, University of Antwerp, Belgium
| | - Sylvia Dewilde
- PPES Laboratory, Department of Biomedical Sciences, University of Antwerp, Belgium
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13
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Ascenzi P, di Masi A, Leboffe L, Fiocchetti M, Nuzzo MT, Brunori M, Marino M. Neuroglobin: From structure to function in health and disease. Mol Aspects Med 2016; 52:1-48. [DOI: 10.1016/j.mam.2016.10.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 10/27/2016] [Accepted: 10/27/2016] [Indexed: 01/01/2023]
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14
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Athwal NS, Alagurajan J, Andreotti AH, Hargrove MS. Role of Reversible Histidine Coordination in Hydroxylamine Reduction by Plant Hemoglobins (Phytoglobins). Biochemistry 2016; 55:5809-5817. [DOI: 10.1021/acs.biochem.6b00775] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Navjot Singh Athwal
- The Roy
J. Carver Department
of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Jagannathan Alagurajan
- The Roy
J. Carver Department
of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Amy H. Andreotti
- 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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15
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The nitrite reductase activity of horse heart carboxymethylated-cytochrome c is modulated by cardiolipin. J Biol Inorg Chem 2016; 21:421-32. [DOI: 10.1007/s00775-016-1351-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/28/2016] [Indexed: 10/22/2022]
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16
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Zhao C, Du W. Dynamic features of carboxy cytoglobin distal mutants investigated by molecular dynamics simulations. J Biol Inorg Chem 2016; 21:251-61. [DOI: 10.1007/s00775-016-1334-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/04/2016] [Indexed: 01/08/2023]
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17
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Bustamante JP, Radusky L, Boechi L, Estrin DA, ten Have A, Martí MA. Evolutionary and Functional Relationships in the Truncated Hemoglobin Family. PLoS Comput Biol 2016; 12:e1004701. [PMID: 26788940 PMCID: PMC4720485 DOI: 10.1371/journal.pcbi.1004701] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 12/10/2015] [Indexed: 12/21/2022] Open
Abstract
Predicting function from sequence is an important goal in current biological research, and although, broad functional assignment is possible when a protein is assigned to a family, predicting functional specificity with accuracy is not straightforward. If function is provided by key structural properties and the relevant properties can be computed using the sequence as the starting point, it should in principle be possible to predict function in detail. The truncated hemoglobin family presents an interesting benchmark study due to their ubiquity, sequence diversity in the context of a conserved fold and the number of characterized members. Their functions are tightly related to O2 affinity and reactivity, as determined by the association and dissociation rate constants, both of which can be predicted and analyzed using in-silico based tools. In the present work we have applied a strategy, which combines homology modeling with molecular based energy calculations, to predict and analyze function of all known truncated hemoglobins in an evolutionary context. Our results show that truncated hemoglobins present conserved family features, but that its structure is flexible enough to allow the switch from high to low affinity in a few evolutionary steps. Most proteins display moderate to high oxygen affinities and multiple ligand migration paths, which, besides some minor trends, show heterogeneous distributions throughout the phylogenetic tree, again suggesting fast functional adaptation. Our data not only deepens our comprehension of the structural basis governing ligand affinity, but they also highlight some interesting functional evolutionary trends.
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Affiliation(s)
- Juan P. Bustamante
- Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Leandro Radusky
- Departamento de Química Biológica e Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Leonardo Boechi
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Darío A. Estrin
- Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Arjen ten Have
- Instituto de Investigación Biológica, CONICET, Universidad Nacional de Mar del Plata. Buenos Aires, Argentina
| | - Marcelo A. Martí
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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18
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Corti P, Ieraci M, Tejero J. Characterization of zebrafish neuroglobin and cytoglobins 1 and 2: Zebrafish cytoglobins provide insights into the transition from six-coordinate to five-coordinate globins. Nitric Oxide 2015; 53:22-34. [PMID: 26721561 DOI: 10.1016/j.niox.2015.12.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 12/11/2015] [Accepted: 12/19/2015] [Indexed: 12/30/2022]
Abstract
Neuroglobin (Ngb) and cytoglobin (Cygb) are two six-coordinate heme proteins of unknown physiological function. Although studies on the mammalian proteins have elucidated aspects of Ngb and Cygb biophysics and indicated potential functions, the properties of non-mammalian Ngbs and Cygbs are largely uncharacterized. We have expressed the recombinant zebrafish proteins Ngb, Cygb1, and Cygb2 in Escherichia coli and characterized their nitrite reduction rates, spectral properties, autoxidation rate constants, redox potentials and lipid binding properties. The three zebrafish proteins can catalyze the reduction of nitrite to nitric oxide with a broad range of reaction rate constants. (Ngb, 0.68 ± 0.04 M(-1) s(-1); Cygb1, 28.6 ± 3.1 M(-1) s(-1); Cygb2, 0.94 ± 0.18 M(-1) s(-1)). We observe that zebrafish Ngb and Cygb2 have comparable spectral features to those of human Ngb and Cygb, consistent with a six-coordinate heme, whereas unexpectedly Cygb1 has a five-coordinate heme, a slower autoxidation and in general has properties more akin to oxygen transport proteins. In agreement with a possible oxygen carrier and nitrite reductase role, we detect mRNA transcript for Cygb1 but not Cygb2 or Ngb in zebrafish blood. Unlike human Cygb, neither of the zebrafish globins binds oleic acid with high affinity. This finding suggests that lipid binding may be a trait acquired later during evolution and not an ancestral property of cytoglobins. Altogether, our results uncover unexpected properties of zebrafish globins and reveal the pivotal role of cytoglobins in the transition of heme globins from six-coordinate to five-coordinate oxygen carriers and nitrite reductases.
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Affiliation(s)
- Paola Corti
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Matthew Ieraci
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jesús Tejero
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA; Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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19
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Ascenzi P, Sbardella D, Fiocchetti M, Santucci R, Coletta M. NO2−-mediated nitrosylation of ferrous microperoxidase-11. J Inorg Biochem 2015; 153:121-127. [DOI: 10.1016/j.jinorgbio.2015.06.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 06/03/2015] [Accepted: 06/30/2015] [Indexed: 11/29/2022]
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20
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Electron self-exchange in hemoglobins revealed by deutero-hemin substitution. J Inorg Biochem 2015; 150:139-47. [DOI: 10.1016/j.jinorgbio.2015.06.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 06/11/2015] [Accepted: 06/14/2015] [Indexed: 11/20/2022]
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21
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Tejero J, Sparacino-Watkins CE, Ragireddy V, Frizzell S, Gladwin MT. Exploring the mechanisms of the reductase activity of neuroglobin by site-directed mutagenesis of the heme distal pocket. Biochemistry 2015; 54:722-33. [PMID: 25554946 PMCID: PMC4410703 DOI: 10.1021/bi501196k] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Neuroglobin
(Ngb) is a six-coordinate globin that can catalyze
the reduction of nitrite to nitric oxide. Although this reaction is
common to heme proteins, the molecular interactions in the heme pocket
that regulate this reaction are largely unknown. We have shown that
the H64L Ngb mutation increases the rate of nitrite reduction by 2000-fold
compared to that of wild-type Ngb [Tiso, M., et al. (2011) J. Biol. Chem. 286, 18277–18289]. Here we explore
the effect of distal heme pocket mutations on nitrite reduction. For
this purpose, we have generated mutations of Ngb residues Phe28(B10),
His64(E7), and Val68(E11). Our results indicate a dichotomy in the
reactivity of deoxy five- and six-coordinate globins toward nitrite.
In hemoglobin and myoglobin, there is a correlation between faster
rates and more negative potentials. However, in Ngb, reaction rates
are apparently related to the distal pocket volume, and redox potential
shows a poor relationship with the rate constants. This suggests a
relationship between the nitrite reduction rate and heme accessibility
in Ngb, particularly marked for His64(E7) mutants. In five-coordinate
globins, His(E7) facilitates nitrite reduction, likely through proton
donation. Conversely, in Ngb, the reduction mechanism does not rely
on the delivery of a proton from the histidine side chain, as His64
mutants show the fastest reduction rates. In fact, the rate observed
for H64A Ngb (1120 M–1 s–1) is
to the best of our knowledge the fastest reported for a heme nitrite
reductase. These differences may be related to a differential stabilization
of the iron–nitrite complexes in five- and six-coordinate globins.
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Affiliation(s)
- Jesús Tejero
- Vascular Medicine Institute, University of Pittsburgh , Pittsburgh, Pennsylvania 15261, United States
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22
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Avella G, Ardiccioni C, Scaglione A, Moschetti T, Rondinelli C, Montemiglio LC, Savino C, Giuffrè A, Brunori M, Vallone B. Engineering the internal cavity of neuroglobin demonstrates the role of the haem-sliding mechanism. ACTA ACUST UNITED AC 2014; 70:1640-8. [DOI: 10.1107/s1399004714007032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/29/2014] [Indexed: 11/10/2022]
Abstract
Neuroglobin is a member of the globin family involved in neuroprotection; it is primarily expressed in the brain and retina of vertebrates. Neuroglobin belongs to the heterogeneous group of hexacoordinate globins that have evolved in animals, plants and bacteria, endowed with the capability of reversible intramolecular coordination, allowing the binding of small gaseous ligands (O2, NO and CO). In a unique fashion among haemoproteins, ligand-binding events in neuroglobin are dependent on the sliding of the haem itself within a preformed internal cavity, as revealed by the crystal structure of its CO-bound derivative. Point mutants of the neuroglobin internal cavity have been engineered and their functional and structural characterization shows that hindering the haem displacement leads to a decrease in CO affinity, whereas reducing the cavity volume without interfering with haem sliding has negligible functional effects.
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23
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Zhao C, Zhang B, Du W. Effects of distal mutation on the dynamic properties of carboxycytoglobin: a molecular dynamics simulation study. J Biol Inorg Chem 2013; 18:947-55. [DOI: 10.1007/s00775-013-1041-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 08/26/2013] [Indexed: 11/29/2022]
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24
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Mukhi N, Dhindwal S, Uppal S, Kumar P, Kaur J, Kundu S. X-ray crystallographic structural characteristics of Arabidopsis hemoglobin I and their functional implications. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1944-56. [PMID: 23485912 DOI: 10.1016/j.bbapap.2013.02.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 02/16/2013] [Accepted: 02/19/2013] [Indexed: 11/24/2022]
Abstract
Genome of the model dicot flowering plant, Arabidopsis thaliana, a popular tool for understanding molecular biology of plant physiology, encodes all three classes of plant hemoglobins that differ in their sequence, ligand binding and spectral properties. As such these globins are of considerable attention. Crystal structures of few members of plant class I nonsymbiotic hemoglobin have been described earlier. Here we report the crystal structure of Arabidopsis class I hemoglobin (AHb1) to 2.2Ǻ and compare its key features with the structures of similar nonsymbiotic hemoglobin from other species. Crystal structure of AHb1 is homologous to the related members with similar globin fold and heme pocket architecture. The structure is homodimeric in the asymmetric unit with both distal and proximal histidines coordinating to the heme iron atom. Residues lining the dimeric interface are also conserved in AHb1 with the exception of additional electrostatic interaction between H112 and E113 of each subunit and that involving Y119 through two water molecules. In addition, differences in heme pocket non-covalent interactions, a novel Ser residue at F7 position, Xe binding site variability, internal cavity topology differences, CD loop conformation and stability and other such properties might explain kinetic variability in AHb1. Detailed cavity analysis of AHb1 showed the presence of a novel long tunnel connecting the distal pockets of both the monomers. Presence of such tunnel, along with conformational heterogeneity observed in the two chains, might suggest cooperative ligand binding and support its role in NO scavenging. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.
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Affiliation(s)
- Nitika Mukhi
- Department of Genetics, University of Delhi South Campus, New Delhi, India
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25
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Abstract
Approximately, 20 years ago, a haemoglobin gene was identified within the genome of the cyanobacterium Nostoc commune. Haemoglobins have now been confirmed in multiple species of photosynthetic microbes beyond N. commune, and the diversity of these proteins has recently come under increased scrutiny. This chapter summarizes the state of knowledge concerning the phylogeny, physiology and chemistry of globins in cyanobacteria and green algae. Sequence information is by far the best developed and the most rapidly expanding aspect of the field. Structural and ligand-binding properties have been described for just a few proteins. Physiological data are available for even fewer. Although activities such as nitric oxide dioxygenation and oxygen scavenging are strong candidates for cellular function, dedicated studies will be required to complete the story on this intriguing and ancient group of proteins.
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26
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Hannibal L, Collins D, Brassard J, Chakravarti R, Vempati R, Dorlet P, Santolini J, Dawson JH, Stuehr DJ. Heme binding properties of glyceraldehyde-3-phosphate dehydrogenase. Biochemistry 2012; 51:8514-29. [PMID: 22957700 DOI: 10.1021/bi300863a] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a glycolytic enzyme that also functions in transcriptional regulation, oxidative stress, vesicular trafficking, and apoptosis. Because GAPDH is required for the insertion of cellular heme into inducible nitric oxide synthase [Chakravarti, R., et al. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 18004-18009], we extensively characterized the heme binding properties of GAPDH. Substoichiometric amounts of ferric heme bound to GAPDH (one heme per GAPDH tetramer) to form a low-spin complex with UV-visible maxima at 362, 418, and 537 nm and when reduced to ferrous gave maxima at 424, 527, and 559 nm. Ferric heme association and dissociation rate constants at 10 °C were as follows: k(on) = 17800 M(-1) s(-1), k(off1) = 7.0 × 10(-3) s(-1), and k(off2) = 3.3 × 10(-4) s(-1) (giving approximate affinities of 19-390 nM). Ferrous heme bound more poorly to GAPDH and dissociated with a k(off) of 4.2 × 10(-3) s(-1). Magnetic circular dichroism, resonance Raman, and electron paramagnetic resonance spectroscopic data on the ferric, ferrous, and ferrous-CO complexes of GAPDH showed that the heme is bis-ligated with His as the proximal ligand. The distal ligand in the ferric complex was not displaced by CN(-) or N(3)(-) but in the ferrous complex could be displaced by CO at a rate of 1.75 s(-1) (for >0.2 mM CO). Studies with heme analogues revealed selectivity toward the coordinating metal and porphyrin ring structure. The GAPDH-heme complex was isolated from bacteria induced to express rabbit GAPDH in the presence of δ-aminolevulinic acid. Our finding of heme binding to GAPDH expands the protein's potential roles. The strength, selectivity, reversibility, and redox sensitivity of heme binding to GAPDH are consistent with it performing heme sensing or heme chaperone-like functions in cells.
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Affiliation(s)
- Luciana Hannibal
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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27
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Sturms R, DiSpirito AA, Fulton DB, Hargrove MS. Hydroxylamine Reduction to Ammonium by Plant and Cyanobacterial Hemoglobins. Biochemistry 2011; 50:10829-35. [DOI: 10.1021/bi201425f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryan Sturms
- Department of Biochemistry,
Biophysics, and Molecular
Biology, Iowa State University, Ames, Iowa
50011, United States
| | - Alan A. DiSpirito
- Department of Biochemistry,
Biophysics, and Molecular
Biology, Iowa State University, Ames, Iowa
50011, United States
| | - D. Bruce Fulton
- Department of Biochemistry,
Biophysics, and Molecular
Biology, Iowa State University, Ames, Iowa
50011, United States
| | - Mark S. Hargrove
- Department of Biochemistry,
Biophysics, and Molecular
Biology, Iowa State University, Ames, Iowa
50011, United States
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28
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Zhang B, Xu J, Li Y, Du W, Fang W. Molecular dynamics simulation of carboxy and deoxy human cytoglobin in solution. J Inorg Biochem 2011; 105:949-56. [DOI: 10.1016/j.jinorgbio.2011.03.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 03/28/2011] [Accepted: 03/28/2011] [Indexed: 11/30/2022]
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29
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Kakar S, Sturms R, Tiffany A, Nix JC, DiSpirito AA, Hargrove MS. Crystal Structures of Parasponia and Trema Hemoglobins: Differential Heme Coordination Is Linked to Quaternary Structure. Biochemistry 2011; 50:4273-80. [DOI: 10.1021/bi2002423] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Smita Kakar
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Ryan Sturms
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Andrea Tiffany
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Jay C. Nix
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Alan A. DiSpirito
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Mark S. Hargrove
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
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30
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Sturms R, DiSpirito AA, Hargrove MS. Plant and Cyanobacterial Hemoglobins Reduce Nitrite to Nitric Oxide under Anoxic Conditions. Biochemistry 2011; 50:3873-8. [DOI: 10.1021/bi2004312] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryan Sturms
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Alan A. DiSpirito
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Mark S. Hargrove
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
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31
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Igamberdiev AU, Bykova NV, Hill RD. Structural and functional properties of class 1 plant hemoglobins. IUBMB Life 2011; 63:146-52. [DOI: 10.1002/iub.439] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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32
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Birukou I, Soman J, Olson JS. Blocking the gate to ligand entry in human hemoglobin. J Biol Chem 2010; 286:10515-29. [PMID: 21193395 DOI: 10.1074/jbc.m110.176271] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
His(E7) to Trp replacements in HbA lead to markedly biphasic bimolecular CO rebinding after laser photolysis. For isolated mutant subunits, the fraction of fast phase increases with increasing [CO], suggesting a competition between binding to an open conformation with an empty E7 channel and relaxation to blocked or closed, slowly reacting states. The rate of conformational relaxation of the open state is ∼18,000 s(-1) in α subunits and ∼10-fold faster in β subunits, ∼175,000 s(-1). Crystal structures were determined for tetrameric α(WT)β(Trp-63) HbCO, α(Trp-58)β(WT) deoxyHb, and Trp-64 deoxy- and CO-Mb as controls. In Trp-63(E7) βCO, the indole side chain is located in the solvent interface, blocking entry into the E7 channel. Similar blocked Trp-64(E7) conformations are observed in the mutant Mb crystal structures. In Trp-58(E7) deoxy-α subunits, the indole side chain fills both the channel and the distal pocket, forming a completely closed state. The bimolecular rate constant for CO binding, k'(CO), to the open conformations of both mutant Hb subunits is ∼80-90 μm(-1) s(-1), whereas k'(CO) for the completely closed states is 1000-fold slower, ∼0.08 μm(-1) s(-1). A transient intermediate with k'(CO) ≈ 0.7 μm(-1) s(-1) is observed after photolysis of Trp-63(E7) βCO subunits and indicates that the indole ring blocks the entrance to the E7 channel, as observed in the crystal structures of Trp(E7) deoxyMb and βCO subunits. Thus, either blocking or completely filling the E7 channel dramatically slows bimolecular binding, providing strong evidence that the E7 channel is the major pathway (≥90%) for ligand entry in human hemoglobin.
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Affiliation(s)
- Ivan Birukou
- Department of Biochemistry and Cell Biology and the W. M. Keck Center for Computational Biology, Rice University, Houston, Texas 77005, USA
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33
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Structure and reactivity of hexacoordinate hemoglobins. Biophys Chem 2010; 152:1-14. [PMID: 20933319 DOI: 10.1016/j.bpc.2010.08.008] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/20/2010] [Accepted: 08/21/2010] [Indexed: 01/07/2023]
Abstract
The heme prosthetic group in hemoglobins is most often attached to the globin through coordination of either one or two histidine side chains. Those proteins with one histidine coordinating the heme iron are called "pentacoordinate" hemoglobins, a group represented by red blood cell hemoglobin and most other oxygen transporters. Those with two histidines are called "hexacoordinate hemoglobins", which have broad representation among eukaryotes. Coordination of the second histidine in hexacoordinate Hbs is reversible, allowing for binding of exogenous ligands like oxygen, carbon monoxide, and nitric oxide. Research over the past several years has produced a fairly detailed picture of the structure and biochemistry of hexacoordinate hemoglobins from several species including neuroglobin and cytoglobin in animals, and the nonsymbiotic hemoglobins in plants. However, a clear understanding of the physiological functions of these proteins remains an elusive goal.
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34
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Yoon J, Herzik MA, Winter MB, Tran R, Olea C, Marletta MA. Structure and properties of a bis-histidyl ligated globin from Caenorhabditis elegans. Biochemistry 2010; 49:5662-70. [PMID: 20518498 DOI: 10.1021/bi100710a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Globins are heme-containing proteins that are best known for their roles in oxygen (O(2)) transport and storage. However, more diverse roles of globins in biology are being revealed, including gas and redox sensing. In the nematode Caenorhabditis elegans, 33 globin or globin-like genes were recently identified, some of which are known to be expressed in the sensory neurons of the worm and linked to O(2) sensing behavior. Here, we describe GLB-6, a novel globin-like protein expressed in the neurons of C. elegans. Recombinantly expressed full-length GLB-6 contains a heme site with spectral features that are similar to those of other bis-histidyl ligated globins, such as neuroglobin and cytoglobin. In contrast to these globins, however, ligands such as CO, NO, and CN(-) do not bind to the heme in GLB-6, demonstrating that the endogenous histidine ligands are likely very tightly coordinated. Additionally, GLB-6 exhibits rapid two-state autoxidation kinetics in the presence of physiological O(2) levels as well as a low redox potential (-193 +/- 2 mV). A high-resolution (1.40 A) crystal structure of the ferric form of the heme domain of GLB-6 confirms both the putative globin fold and bis-histidyl ligation and also demonstrates key structural features that can be correlated with the unusual ligand binding and redox properties exhibited by the full-length protein. Taken together, the biochemical properties of GLB-6 suggest that this neural protein would most likely serve as a physiological sensor for O(2) in C. elegans via redox signaling and/or electron transfer.
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Affiliation(s)
- Jungjoo Yoon
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
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35
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Sturms R, Kakar S, Trent J, Hargrove MS. Trema and parasponia hemoglobins reveal convergent evolution of oxygen transport in plants. Biochemistry 2010; 49:4085-93. [PMID: 20377207 DOI: 10.1021/bi1002844] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
All plants contain hemoglobins that fall into distinct phylogenetic classes. The subset of plants that carry out symbiotic nitrogen fixation expresses hemoglobins that scavenge and transport oxygen to bacterial symbiotes within root nodules. These "symbiotic" oxygen transport hemoglobins are distinct in structure and function from the nonoxygen transport ("nonsymbiotic") Hbs found in all plants. Hemoglobins found in two closely related plants present a paradox concerning hemoglobin structure and function. Parasponia andersonii is a nitrogen-fixing plant that expresses a symbiotic hemoglobin (ParaHb) characteristic of oxygen transport hemoglobins in having a pentacoordinate ferrous heme iron, moderate oxygen affinity, and a relatively rapid oxygen dissociation rate constant. A close relative that does not fix nitrogen, Trema tomentosa, expresses hemoglobin (TremaHb) sharing 93% amino acid identity to ParaHb, but its phylogeny predicts a typical nonsymbiotic hemoglobin with a hexacoordinate heme iron, high oxygen affinity, and slow oxygen dissociation rate constant. Here we characterize heme coordination and oxygen binding in TremaHb and ParaHb to investigate whether or not two hemoglobins with such high sequence similarity are actually so different in functional behavior. Our results indicate that the two proteins resemble nonsymbiotic hemoglobins in the ferric oxidation state and symbiotic hemoglobins in the ferrous oxidation state. They differ from each other only in oxygen affinity and oxygen dissociation rate constants, two factors key to their different functions. These results demonstrate distinct mechanisms for convergent evolution of oxygen transport in different phylogenetic classes of plant hemoglobins.
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Affiliation(s)
- Ryan Sturms
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA
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36
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Gell DA, Feng L, Zhou S, Jeffrey PD, Bendak K, Gow A, Weiss MJ, Shi Y, Mackay JP. A cis-proline in alpha-hemoglobin stabilizing protein directs the structural reorganization of alpha-hemoglobin. J Biol Chem 2009; 284:29462-9. [PMID: 19706593 PMCID: PMC2785579 DOI: 10.1074/jbc.m109.027045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Revised: 07/16/2009] [Indexed: 11/06/2022] Open
Abstract
alpha-Hemoglobin (alphaHb) stabilizing protein (AHSP) is expressed in erythropoietic tissues as an accessory factor in hemoglobin synthesis. AHSP forms a specific complex with alphaHb and suppresses the heme-catalyzed evolution of reactive oxygen species by converting alphaHb to a conformation in which the heme is coordinated at both axial positions by histidine side chains (bis-histidyl coordination). Currently, the detailed mechanism by which AHSP induces structural changes in alphaHb has not been determined. Here, we present x-ray crystallography, NMR spectroscopy, and mutagenesis data that identify, for the first time, the importance of an evolutionarily conserved proline, Pro(30), in loop 1 of AHSP. Mutation of Pro(30) to a variety of residue types results in reduced ability to convert alphaHb. In complex with alphaHb, AHSP Pro(30) adopts a cis-peptidyl conformation and makes contact with the N terminus of helix G in alphaHb. Mutations that stabilize the cis-peptidyl conformation of free AHSP, also enhance the alphaHb conversion activity. These findings suggest that AHSP loop 1 can transmit structural changes to the heme pocket of alphaHb, and, more generally, highlight the importance of cis-peptidyl prolyl residues in defining the conformation of regulatory protein loops.
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Affiliation(s)
- David A Gell
- School of Molecular and Microbial Biosciences, University of Sydney, New South Wales 2006, Australia.
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37
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Suits MDL, Lang J, Pal GP, Couture M, Jia Z. Structure and heme binding properties of Escherichia coli O157:H7 ChuX. Protein Sci 2009; 18:825-38. [PMID: 19319934 PMCID: PMC2762594 DOI: 10.1002/pro.84] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
For many pathogenic microorganisms, iron acquisition from host heme sources stimulates growth, multiplication, ultimately enabling successful survival and colonization. In gram-negative Escherichia coli O157:H7, Shigella dysenteriae and Yersinia enterocolitica the genes encoded within the heme utilization operon enable the effective uptake and utilization of heme as an iron source. While the complement of proteins responsible for heme internalization has been determined in these organisms, the fate of heme once it has reached the cytoplasm has only recently begun to be resolved. Here we report the first crystal structure of ChuX, a member of the conserved heme utilization operon from pathogenic E. coli O157:H7 determined at 2.05 A resolution. ChuX forms a dimer which remarkably given low sequence homology, displays a very similar fold to the monomer structure of ChuS and HemS, two other heme utilization proteins. Absorption spectral analysis of heme reconstituted ChuX demonstrates that ChuX binds heme in a 1:1 manner implying that each ChuX homodimer has the potential to coordinate two heme molecules in contrast to ChuS and HemS where only one heme molecule is bound. Resonance Raman spectroscopy indicates that the heme of ferric ChuX is composed of a mixture of coordination states: 5-coordinate and high-spin, 6-coordinate and low-spin, and 6-coordinate and high-spin. In contrast, the reduced ferrous form displays mainly a 5-coordinate and high-spin state with a minor contribution from a 6-coordinate and low-spin state. The nu(Fe-CO) and nu(C-O) frequencies of ChuX-bound CO fall on the correlation line expected for histidine-coordinated hemoproteins indicating that the fifth axial ligand of the ferrous heme is the imidazole ring of a histidine residue. Based on sequence and structural comparisons, we designed a number of site-directed mutations in ChuX to probe the heme binding sites and dimer interface. Spectral analysis of ChuX and mutants suggests involvement of H65 and H98 in heme coordination as mutations of both residues were required to abolish the formation of the hexacoordination state of heme-bound ChuX.
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Affiliation(s)
- Michael D L Suits
- Department of Biochemistry, Queen's UniversityKingston, Ontario, Canada K7L 3N6
| | - Jérôme Lang
- Département de Biochimie et de Microbiologie, Université LavalQuebec City, Quebec, Canada G1K 7P4
| | - Gour P Pal
- Department of Biochemistry, Queen's UniversityKingston, Ontario, Canada K7L 3N6
| | - Manon Couture
- Département de Biochimie et de Microbiologie, Université LavalQuebec City, Quebec, Canada G1K 7P4
| | - Zongchao Jia
- Department of Biochemistry, Queen's UniversityKingston, Ontario, Canada K7L 3N6,*Correspondence to: Zongchao Jia, Department of Biochemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6. E-mail:
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Smagghe BJ, Halder P, Hargrove MS. Measurement of distal histidine coordination equilibrium and kinetics in hexacoordinate hemoglobins. Methods Enzymol 2008; 436:359-78. [PMID: 18237643 DOI: 10.1016/s0076-6879(08)36020-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
The kinetics of ligand binding to hemoglobins has been measured for decades. Initially, these studies were confined to readily available pentacoordinate oxygen transport proteins like myoglobin, leghemoglobin, and red blood cell hemoglobin. Bimolecular ligand binding to these proteins is relatively simple, as ligand association is largely unimpeded at the heme iron. Although many techniques have been used to examine these reactions in the past, stopped-flow rapid mixing and flash photolysis are the most common ways to measure rate constants for ligand association and dissociation. Expression of recombinant proteins has allowed for examination of many newly discovered hemoglobins. The hexacoordinate hemoglobins are one such group of proteins that exhibit more complex binding kinetics than pentacoordinate hemoglobins due to reversible intramolecular coordination by a histidine side chain. Here, we describe methods for characterizing the kinetics of ligand binding to hexacoordinate hemoglobins with a focus on measurement of histidine coordination and exogenous ligand binding in both the ferrous and the ferric oxidation states.
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Affiliation(s)
- Benoit J Smagghe
- Immune Disease Institute, Harvard Medical School, Boston, Massachusetts
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Smagghe BJ, Trent JT, Hargrove MS. NO dioxygenase activity in hemoglobins is ubiquitous in vitro, but limited by reduction in vivo. PLoS One 2008; 3:e2039. [PMID: 18446211 PMCID: PMC2323109 DOI: 10.1371/journal.pone.0002039] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Accepted: 02/03/2008] [Indexed: 12/02/2022] Open
Abstract
Genomics has produced hundreds of new hemoglobin sequences with examples in nearly every living organism. Structural and biochemical characterizations of many recombinant proteins reveal reactions, like oxygen binding and NO dioxygenation, that appear general to the hemoglobin superfamily regardless of whether they are related to physiological function. Despite considerable attention to “hexacoordinate” hemoglobins, which are found in nearly every plant and animal, no clear physiological role(s) has been assigned to them in any species. One popular and relevant hypothesis for their function is protection against NO. Here we have tested a comprehensive representation of hexacoordinate hemoglobins from plants (rice hemoglobin), animals (neuroglobin and cytoglobin), and bacteria (Synechocystis hemoglobin) for their abilities to scavenge NO compared to myoglobin. Our experiments include in vitro comparisons of NO dioxygenation, ferric NO binding, NO-induced reduction, NO scavenging with an artificial reduction system, and the ability to substitute for a known NO scavenger (flavohemoglobin) in E. coli. We conclude that none of these tests reveal any distinguishing predisposition toward a role in NO scavenging for the hxHbs, but that any hemoglobin could likely serve this role in the presence of a mechanism for heme iron re-reduction. Hence, future research to test the role of Hbs in NO scavenging would benefit more from the identification of cognate reductases than from in vitro analysis of NO and O2 binding.
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Affiliation(s)
- Benoit J. Smagghe
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - James T. Trent
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
| | - Mark S. Hargrove
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
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40
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Vinogradov SN, Moens L. Diversity of Globin Function: Enzymatic, Transport, Storage, and Sensing. J Biol Chem 2008; 283:8773-7. [DOI: 10.1074/jbc.r700029200] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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41
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Hoy JA, Hargrove MS. The structure and function of plant hemoglobins. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:371-9. [PMID: 18321722 DOI: 10.1016/j.plaphy.2007.12.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Indexed: 05/24/2023]
Abstract
Plants, like humans, contain hemoglobin. Three distinct types of hemoglobin exist in plants: symbiotic, non-symbiotic, and truncated hemoglobins. Crystal structures and other structural and biophysical techniques have revealed important knowledge about ligand binding and conformational stabilization in all three types. In symbiotic hemoglobins (leghemoglobins), ligand binding regulatory mechanisms have been shown to differ dramatically from myoglobin and red blood cell hemoglobin. In the non-symbiotic hemoglobins found in all plants, crystal structures and vibrational spectroscopy have revealed the nature of the structural transition between the hexacoordinate and ligand-bound states. In truncated hemoglobins, the abbreviated globin is porous, providing tunnels that may assist in ligand binding, and the bound ligand is stabilized by more than one distal pocket residue. Research has implicated these plant hemoglobins in a number of possible functions differing among hemoglobin types, and possibly between plant species.
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Affiliation(s)
- Julie A Hoy
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50014, USA
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Hoy JA, Smagghe BJ, Halder P, Hargrove MS. Covalent heme attachment in Synechocystis hemoglobin is required to prevent ferrous heme dissociation. Protein Sci 2007; 16:250-60. [PMID: 17242429 PMCID: PMC2203299 DOI: 10.1110/ps.062572607] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Synechocystis hemoglobin contains an unprecedented covalent bond between a nonaxial histidine side chain (H117) and the heme 2-vinyl. This bond has been previously shown to stabilize the ferric protein against denaturation, and also to affect the kinetics of cyanide association. However, it is unclear why Synechocystis hemoglobin would require the additional degree of stabilization accompanying the His117-heme 2-vinyl bond because it also displays endogenous bis-histidyl axial heme coordination, which should greatly assist heme retention. Furthermore, the mechanism by which the His117-heme 2-vinyl bond affects ligand binding has not been reported, nor has any investigation of the role of this bond on the structure and function of the protein in the ferrous oxidation state. Here we report an investigation of the role of the Synechocystis hemoglobin His117-heme 2-vinyl bond on structure, heme coordination, exogenous ligand binding, and stability in both the ferrous and ferric oxidation states. Our results reveal that hexacoordinate Synechocystis hemoglobin lacking this bond is less stable in the ferrous oxidation state than the ferric, which is surprising in light of our understanding of pentacoordinate Hb stability, in which the ferric protein is always less stable. It is also demonstrated that removal of the His117-heme 2-vinyl bond increases the affinity constant for intramolecular histidine coordination in the ferric oxidation state, thus presenting greater competition for the ligand binding site and lowering the observed rate and affinity constants for exogenous ligands.
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Affiliation(s)
- Julie A Hoy
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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