1
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Galinato MGI, Wyant C, Lombardo AL, MacIsaac EK, Rios-Martinez DA, Kimrey CD, Castro AA. Generating globin-like reactivities in [human serum albumin-Fe II(heme)] complex through N-donor ligand addition. J Inorg Biochem 2024; 262:112743. [PMID: 39357192 DOI: 10.1016/j.jinorgbio.2024.112743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2024] [Revised: 09/11/2024] [Accepted: 09/20/2024] [Indexed: 10/04/2024]
Abstract
Human serum albumin (HSA) has a strong binding affinity for heme b, forming a complex in a 1:1 ratio with the co-factor ([HSA-FeIIIheme]). This system displays spectroscopic and functional properties comparable to globins when chemical derivatives mimicking them are incorporated into the protein matrix. The aim of this study is to generate globin-like systems using [HSA-FeIIIheme] as a protein template and binding N-donor ligands (imidazole, Im; and 1-methylimidazole, 1-MeIm) to construct artificial [HSA-Fe(heme)-(N-donor)] complexes. Their electronic structure and binding thermodynamics are investigated using UV-vis and (synchronous) fluorescence spectroscopies, while ligand-protein interactions are visualized using docking simulations. The imidazole derivatives have a strong affinity for [HSA-FeIIIheme] (K ∼ 104-106), where the spontaneous binding of Im and 1-MeIm are dominated by entropic and enthalpic effects, respectively. The reduced form of the [HSA-Fe(heme)-(N-donor)] complexes demonstrate nitrite reductase (NiR) activity similar to that observed in globins, but with significant differences in their rates. [HSA-FeIIheme-(1-MeIm)] reduces nitrite ∼4× faster than the Im analogue, and ∼ 30× faster than myoglobin (Mb). The enhanced NiR activity of [HSA-FeIIheme-(1-MeIm)] is a cumulative effect of several factors including a slightly expanded and more optimal heme binding pocket, nearby residues as possible proton sources, and a H-bonding interaction between 1-MeIm and residues Arg160 and Lys181 that may have a long-distance influence on the heme π electron density.
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Affiliation(s)
- Mary Grace I Galinato
- Department of Chemistry & Physics, Jacksonville University, 2800 University Blvd N, Jacksonville, FL 32211, United States; School of Science - Chemistry, Penn State Behrend, 4205 College Dr., Erie, PA 16563, United States.
| | - Christopher Wyant
- School of Science - Chemistry, Penn State Behrend, 4205 College Dr., Erie, PA 16563, United States
| | - Ashley L Lombardo
- School of Science - Chemistry, Penn State Behrend, 4205 College Dr., Erie, PA 16563, United States
| | - Ethan K MacIsaac
- Department of Chemistry & Physics, Jacksonville University, 2800 University Blvd N, Jacksonville, FL 32211, United States
| | - Daniella A Rios-Martinez
- School of Science - Chemistry, Penn State Behrend, 4205 College Dr., Erie, PA 16563, United States
| | - Christopher D Kimrey
- School of Science - Chemistry, Penn State Behrend, 4205 College Dr., Erie, PA 16563, United States
| | - Alexandra Alfonso Castro
- School of Science - Chemistry, Penn State Behrend, 4205 College Dr., Erie, PA 16563, United States
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2
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Deng Y, Carnevale V, Ditchfield R, Pletneva EV. Applications of the Newly Developed Force-Field Parameters Uncover a Dynamic Nature of Ω-Loop C in the Lys-Ligated Alkaline Form of Cytochrome c. J Phys Chem B 2024; 128:5935-5949. [PMID: 38864552 DOI: 10.1021/acs.jpcb.4c00625] [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: 06/13/2024]
Abstract
Lys-ligated cytochromes make up an emerging family of heme proteins. Density functional theory calculations on the amine/imidazole-ligated c-type ferric heme were employed to develop force-field parameters for molecular dynamics (MD) simulations of structural and dynamic features of these proteins. The new force-field parameters were applied to the alkaline form of yeast iso-1 cytochrome c to rationalize discrepancies resulting from distinct experimental conditions in prior structural studies and to provide insights into the mechanisms of the alkaline transition. Our simulations have revealed the dynamic nature of Ω-loop C in the Lys-ligated protein and its unfolding in the Lys-ligated conformer having this loop in the same position as in the native Met-ligated protein. The proximity of Tyr67 or Tyr74 to the Lys ligand of ferric heme iron suggests a possible mechanism of the backward alkaline transition where a proton donor Tyr assists in Lys dissociation. The developed force-field parameters will be useful in structural and dynamic characterization of other native or engineered Lys-ligated heme proteins.
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Affiliation(s)
- Yunling Deng
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Vincenzo Carnevale
- Institute for Genomics and Evolutionary Medicine, Institute for Computational Molecular Science, and Department of Biology, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Robert Ditchfield
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Ekaterina V Pletneva
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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3
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Kroneck PMH. Nature's nitrite-to-ammonia expressway, with no stop at dinitrogen. J Biol Inorg Chem 2021; 27:1-21. [PMID: 34865208 PMCID: PMC8840924 DOI: 10.1007/s00775-021-01921-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/22/2021] [Indexed: 12/26/2022]
Abstract
Since the characterization of cytochrome c552 as a multiheme nitrite reductase, research on this enzyme has gained major interest. Today, it is known as pentaheme cytochrome c nitrite reductase (NrfA). Part of the NH4+ produced from NO2- is released as NH3 leading to nitrogen loss, similar to denitrification which generates NO, N2O, and N2. NH4+ can also be used for assimilatory purposes, thus NrfA contributes to nitrogen retention. It catalyses the six-electron reduction of NO2- to NH4+, hosting four His/His ligated c-type hemes for electron transfer and one structurally differentiated active site heme. Catalysis occurs at the distal side of a Fe(III) heme c proximally coordinated by lysine of a unique CXXCK motif (Sulfurospirillum deleyianum, Wolinella succinogenes) or, presumably, by the canonical histidine in Campylobacter jejeuni. Replacement of Lys by His in NrfA of W. succinogenes led to a significant loss of enzyme activity. NrfA forms homodimers as shown by high resolution X-ray crystallography, and there exist at least two distinct electron transfer systems to the enzyme. In γ-proteobacteria (Escherichia coli) NrfA is linked to the menaquinol pool in the cytoplasmic membrane through a pentaheme electron carrier (NrfB), in δ- and ε-proteobacteria (S. deleyianum, W. succinogenes), the NrfA dimer interacts with a tetraheme cytochrome c (NrfH). Both form a membrane-associated respiratory complex on the extracellular side of the cytoplasmic membrane to optimize electron transfer efficiency. This minireview traces important steps in understanding the nature of pentaheme cytochrome c nitrite reductases, and discusses their structural and functional features.
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Affiliation(s)
- Peter M H Kroneck
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
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4
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Control of distal lysine coordination in a monomeric hemoglobin: A role for heme peripheral interactions. J Inorg Biochem 2021; 219:111437. [PMID: 33892380 DOI: 10.1016/j.jinorgbio.2021.111437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 03/20/2021] [Accepted: 03/20/2021] [Indexed: 12/25/2022]
Abstract
THB1 is a monomeric truncated hemoglobin (TrHb) found in the cytoplasm of the green alga Chlamydomonas reinhardtii. The canonical heme coordination scheme in hemoglobins is a proximal histidine ligand and an open distal site. In THB1, the latter site is occupied by Lys53, which is likely to facilitate Fe(II)/Fe(III) redox cycling but hinders dioxygen binding, two features inherent to the NO dioxygenase activity of the protein. TrHb surveys show that a lysine at a position aligning with Lys53 is an insufficient determinant of coordination, and in this study, we sought to identify factors controlling lysine affinity for the heme iron. We solved the "Lys-off" X-ray structure of THB1, represented by the cyanide adduct of the Fe(III) protein, and hypothesized that interactions that differ between the known "Lys-on" structure and the Lys-off structure participate in the control of Lys53 affinity for the heme iron. We applied an experimental approach (site-directed mutagenesis, heme modification, pH titrations in the Fe(III) and Fe(II) states) and a computational approach (MD simulations in the Fe(II) state) to assess the role of heme propionate-protein interactions, distal helix capping, and the composition of the distal pocket. All THB1 modifications resulted in a weakening of lysine affinity and affected the coupling between Lys53 proton binding and heme redox potential. The results supported the importance of specific heme peripheral interactions for the pH stability of iron coordination and the ability of the protein to undergo redox reactions.
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5
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Paradisi A, Bellei M, Paltrinieri L, Bortolotti CA, Di Rocco G, Ranieri A, Borsari M, Sola M, Battistuzzi G. Binding of S. cerevisiae iso-1 cytochrome c and its surface lysine-to-alanine variants to cardiolipin: charge effects and the role of the lipid to protein ratio. J Biol Inorg Chem 2020; 25:467-487. [DOI: 10.1007/s00775-020-01776-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/06/2020] [Indexed: 11/30/2022]
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6
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Improved rate of substrate oxidation catalyzed by genetically-engineered myoglobin. Arch Biochem Biophys 2018; 639:44-51. [DOI: 10.1016/j.abb.2017.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 12/13/2017] [Accepted: 12/19/2017] [Indexed: 12/13/2022]
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7
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Nye DB, Preimesberger MR, Majumdar A, Lecomte JTJ. Histidine-Lysine Axial Ligand Switching in a Hemoglobin: A Role for Heme Propionates. Biochemistry 2018; 57:631-644. [PMID: 29271191 DOI: 10.1021/acs.biochem.7b01155] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The hemoglobin of Synechococcus sp. PCC 7002, GlbN, is a monomeric group I truncated protein (TrHb1) that coordinates the heme iron with two histidine ligands at neutral pH. One of these is the distal histidine (His46), a residue that can be displaced by dioxygen and other small molecules. Here, we show with mutagenesis, electronic absorption spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy that at high pH and exclusively in the ferrous state, Lys42 competes with His46 for the iron coordination site. When b heme is originally present, the population of the lysine-bound species remains too small for detailed characterization; however, the population can be increased significantly by using dimethyl-esterified heme. Electronic absorption and NMR spectroscopies showed that the reversible ligand switching process occurs with an apparent pKa of 9.3 and a Lys-ligated population of ∼60% at the basic pH limit in the modified holoprotein. The switching rate, which is slow on the chemical shift time scale, was estimated to be 20-30 s-1 by NMR exchange spectroscopy. Lys42-His46 competition and attendant conformational rearrangement appeared to be related to weakened bis-histidine ligation and enhanced backbone dynamics in the ferrous protein. The pH- and redox-dependent ligand exchange process observed in GlbN illustrates the structural plasticity allowed by the TrHb1 fold and demonstrates the importance of electrostatic interactions at the heme periphery for achieving axial ligand selection. An analogy is drawn to the alkaline transition of cytochrome c, in which Lys-Met competition is detected at alkaline pH, but, in contrast to GlbN, in the ferric state only.
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Affiliation(s)
- Dillon B Nye
- T. C. Jenkins Department of Biophysics, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Matthew R Preimesberger
- T. C. Jenkins Department of Biophysics, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Ananya Majumdar
- Biomolecular NMR Center, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Juliette T J Lecomte
- T. C. Jenkins Department of Biophysics, Johns Hopkins University , Baltimore, Maryland 21218, United States
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8
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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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9
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Preimesberger MR, Majumdar A, Lecomte JTJ. Dynamics of Lysine as a Heme Axial Ligand: NMR Analysis of the Chlamydomonas reinhardtii Hemoglobin THB1. Biochemistry 2017; 56:551-569. [DOI: 10.1021/acs.biochem.6b00926] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Matthew R. Preimesberger
- T.
C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ananya Majumdar
- Biomolecular
NMR Center, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Juliette T. J. Lecomte
- T.
C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
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10
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Hines JP, Smith AT, Jacob JP, Lukat-Rodgers GS, Barr I, Rodgers KR, Guo F, Burstyn JN. CO and NO bind to Fe(II) DiGeorge critical region 8 heme but do not restore primary microRNA processing activity. J Biol Inorg Chem 2016; 21:1021-1035. [PMID: 27766492 DOI: 10.1007/s00775-016-1398-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/10/2016] [Indexed: 01/29/2023]
Abstract
The RNA-binding heme protein DiGeorge critical region 8 (DGCR8) and its ribonuclease partner Drosha cleave primary transcripts of microRNA (pri-miRNA) as part of the canonical microRNA (miRNA) processing pathway. Previous studies show that bis-cysteine thiolate-coordinated Fe(III) DGCR8 supports pri-miRNA processing activity, while Fe(II) DGCR8 does not. In this study, we further characterized Fe(II) DGCR8 and tested whether CO or NO might bind and restore pri-miRNA processing activity to the reduced protein. Fe(II) DGCR8 RNA-binding heme domain (Rhed) undergoes a pH-dependent transition from 6-coordinate to 5-coordinate, due to protonation and loss of a lysine ligand; the ligand bound throughout the pH change is a histidine. Fe(II) Rhed binds CO and NO from 6- and 5-coordinate states, forming common CO and NO adducts at all pHs. Fe(II)-CO Rhed is 6-coordinate, low-spin, and pH insensitive with the histidine ligand retained, suggesting that the protonatable lysine ligand has been replaced by CO. Fe(II)-NO Rhed is 5-coordinate and pH insensitive. Fe(II)-NO also forms slowly upon reaction of Fe(III) Rhed with excess NO via a stepwise process. Heme reduction by NO is rate-limiting, and the rate would be negligible at physiological NO concentrations. Importantly, in vitro pri-miRNA processing assays show that both CO- and NO-bound DGCR8 species are inactive. Fe(II), Fe(II)-CO, and Fe(II)-NO Rhed do not bear either of the cysteine ligands found in the Fe(III) state. These data support a model in which the bis-cysteine thiolate ligand environment of Fe(III) DGCR8 is necessary for establishing proper pri-miRNA binding and enabling processing activity.
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Affiliation(s)
- Judy P Hines
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI, 53706-1322, USA
| | - Aaron T Smith
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD, 21250-0001, USA
| | - Jose P Jacob
- Department of Biological Chemistry, David Geffen School of Medicine, Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 90095-3075, USA
| | - Gudrun S Lukat-Rodgers
- Department of Chemistry and Molecular Biology, North Dakota State University, Fargo, ND, 58108-6050, USA
| | - Ian Barr
- Department of Biological Chemistry, David Geffen School of Medicine, Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 90095-3075, USA
| | - Kenton R Rodgers
- Department of Chemistry and Molecular Biology, North Dakota State University, Fargo, ND, 58108-6050, USA
| | - Feng Guo
- Department of Biological Chemistry, David Geffen School of Medicine, Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 90095-3075, USA
| | - Judith N Burstyn
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, WI, 53706-1322, USA.
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11
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Giovani S, Singh R, Fasan R. Efficient conversion of primary azides to aldehydes catalyzed by active site variants of myoglobin. Chem Sci 2015; 7:234-239. [PMID: 26900445 PMCID: PMC4754990 DOI: 10.1039/c5sc02857d] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 09/28/2015] [Indexed: 12/19/2022] Open
Abstract
The oxidation of primary azides to aldehydes constitutes a convenient but underdeveloped transformation for which no efficient methods are available. Here, we demonstrate that engineered variants of the hemoprotein myoglobin can catalyze this transformation with high efficiency (up to 8,500 turnovers) and selectivity across a range of structurally diverse aryl-substituted primary azides. Mutagenesis of the 'distal' histidine residue was particularly effective in enhancing the azide oxidation reactivity of myoglobin, enabling these reactions to proceed in good to excellent yields (37-89%) and to be carried out at a synthetically useful scale. Kinetic isotope effect, isotope labeling, and substrate binding experiments support a mechanism involving heme-catalyzed decomposition of the organic azide followed by alpha hydrogen deprotonation to generate an aldimine which, upon hydrolysis, releases the aldehyde product. This work provides the first example of a biocatalytic azide-to-aldehyde conversion and expands the range of non-native chemical transformations accessible through hemoprotein-mediated catalysis.
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Affiliation(s)
- Simone Giovani
- Department of Chemistry , University of Rochester , 120 Trustee Rd , Rochester , New York 14627 , USA .
| | - Ritesh Singh
- Department of Chemistry , University of Rochester , 120 Trustee Rd , Rochester , New York 14627 , USA .
| | - Rudi Fasan
- Department of Chemistry , University of Rochester , 120 Trustee Rd , Rochester , New York 14627 , USA .
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12
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Smith AD, Modi AR, Sun S, Dawson JH, Wilks A. Spectroscopic Determination of Distinct Heme Ligands in Outer-Membrane Receptors PhuR and HasR of Pseudomonas aeruginosa. Biochemistry 2015; 54:2601-12. [PMID: 25849630 DOI: 10.1021/acs.biochem.5b00017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Pseudomonas aeruginosa PAO1 encodes two outer membrane receptors, PhuR (Pseudomonas heme uptake) and HasR (heme assimilation system). The HasR receptor acquires heme through interaction with a secreted hemophore, HasAp. The non-hemophore-dependent PhuR is encoded along with proteins required for heme translocation into the cytoplasm. Herein, we report the isolation and characterization of the HasR and PhuR receptors. Absorption and MCD spectroscopy confirmed that, similar to other Gram-negative OM receptors, HasR coordinates heme through the conserved N-terminal plug His-221 and His-624 of the surface-exposed FRAP-loop. In contrast, PhuR showed distinct absorption and MCD spectra consistent with coordination through a Tyr residue. Sequence alignment of PhuR with all known Gram-negative OM heme receptors revealed a lack of a conserved His within the FRAP loop but two Tyr residues at positions 519 and 529. Site-directed mutagenesis and spectroscopic characterization confirmed Tyr-519 and the N-terminal plug His-124 provide the heme ligands in PhuR. We propose that PhuR and HasR represent nonredundant heme receptors capable of sensing and accessing heme across a wide range of physiological conditions on colonization and infection of the host.
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Affiliation(s)
- Aaron D Smith
- †Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, United States
| | - Anuja R Modi
- ‡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
| | - Angela Wilks
- †Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, United States
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13
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M’thiruaine CM, Friedrich HB, Nyawade EA, Omondi B. Syntheses and structural characterization of 2,4,6-trimethylaniline complexes of iron carbonyls. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.09.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Johnson EA, Rice S, Preimesberger MR, Nye DB, Gilevicius L, Wenke BB, Brown JM, Witman GB, Lecomte JTJ. Characterization of THB1, a Chlamydomonas reinhardtii truncated hemoglobin: linkage to nitrogen metabolism and identification of lysine as the distal heme ligand. Biochemistry 2014; 53:4573-89. [PMID: 24964018 PMCID: PMC4108185 DOI: 10.1021/bi5005206] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/23/2014] [Indexed: 12/21/2022]
Abstract
The nuclear genome of the model organism Chlamydomonas reinhardtii contains genes for a dozen hemoglobins of the truncated lineage. Of those, THB1 is known to be expressed, but the product and its function have not yet been characterized. We present mutagenesis, optical, and nuclear magnetic resonance data for the recombinant protein and show that at pH near neutral in the absence of added ligand, THB1 coordinates the heme iron with the canonical proximal histidine and a distal lysine. In the cyanomet state, THB1 is structurally similar to other known truncated hemoglobins, particularly the heme domain of Chlamydomonas eugametos LI637, a light-induced chloroplastic hemoglobin. Recombinant THB1 is capable of binding nitric oxide (NO(•)) in either the ferric or ferrous state and has efficient NO(•) dioxygenase activity. By using different C. reinhardtii strains and growth conditions, we demonstrate that the expression of THB1 is under the control of the NIT2 regulatory gene and that the hemoglobin is linked to the nitrogen assimilation pathway.
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Affiliation(s)
- Eric A. Johnson
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Selena
L. Rice
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | | | - Dillon B. Nye
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Lukas Gilevicius
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Belinda B. Wenke
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jason M. Brown
- Department
of Cell and Developmental Biology, University
of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - George B. Witman
- Department
of Cell and Developmental Biology, University
of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - Juliette T. J. Lecomte
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
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15
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Battistuzzi G, Bortolotti CA, Bellei M, Di Rocco G, Salewski J, Hildebrandt P, Sola M. Role of Met80 and Tyr67 in the Low-pH Conformational Equilibria of Cytochrome c. Biochemistry 2012; 51:5967-78. [DOI: 10.1021/bi3007302] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gianantonio Battistuzzi
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
| | - Carlo Augusto Bortolotti
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
| | - Marzia Bellei
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
| | - Giulia Di Rocco
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
| | - Johannes Salewski
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Marco Sola
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
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