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Das S, Kumar P. Exploring the carbonic anhydrase-mimetic [(PMDTA) 2ZnII2(OH -) 2] 2+ for nitric oxide monooxygenation. Dalton Trans 2024; 53:6173-6177. [PMID: 38501600 DOI: 10.1039/d4dt00407h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
In biology, nitrite (NO2-) serves as a storage pool of nitric oxide (NO); however, the formation of NO2- from NO is still under investigation. Here, we report the NO monooxygenation (NOM) reaction of a ZnII-hydroxide complex (1), producing a ZnII-nitrito complex {2, (ZnII-NO2-)} + H2.
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Affiliation(s)
- Sandip Das
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Pankaj Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
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2
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De Simone G, di Masi A, Pasquadibisceglie A, Coletta A, Sebastiani F, Smulevich G, Coletta M, Ascenzi P. Nitrobindin versus myoglobin: A comparative structural and functional study. J Inorg Biochem 2024; 250:112387. [PMID: 37914583 DOI: 10.1016/j.jinorgbio.2023.112387] [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: 04/12/2023] [Revised: 09/20/2023] [Accepted: 09/24/2023] [Indexed: 11/03/2023]
Abstract
Most hemoproteins display an all-α-helical fold, showing the classical three on three (3/3) globin structural arrangement characterized by seven or eight α-helical segments that form a sandwich around the heme. Over the last decade, a completely distinct class of heme-proteins called nitrobindins (Nbs), which display an all-β-barrel fold, has been identified and characterized from both structural and functional perspectives. Nbs are ten-stranded anti-parallel all-β-barrel heme-proteins found across the evolutionary ladder, from bacteria to Homo sapiens. Myoglobin (Mb), commonly regarded as the prototype of monomeric all-α-helical globins, is involved along with the oligomeric hemoglobin (Hb) in diatomic gas transport, storage, and sensing, as well as in the detoxification of reactive nitrogen and oxygen species. On the other hand, the function(s) of Nbs is still obscure, even though it has been postulated that they might participate to O2/NO signaling and metabolism. This function might be of the utmost importance in poorly oxygenated tissues, such as the eye's retina, where a delicate balance between oxygenation and blood flow (regulated by NO) is crucial. Dysfunction in this balance is associated with several pathological conditions, such as glaucoma and diabetic retinopathy. Here a detailed comparison of the structural, spectroscopic, and functional properties of Mb and Nbs is reported to shed light on the similarities and differences between all-α-helical and all-β-barrel heme-proteins.
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Affiliation(s)
| | | | | | | | - Federico Sebastiani
- Dipartimento di Chimica "Ugo Schiff" (DICUS), Università di Firenze, 50019 Sesto Fiorentino, FI, Italy
| | - Giulietta Smulevich
- Dipartimento di Chimica "Ugo Schiff" (DICUS), Università di Firenze, 50019 Sesto Fiorentino, FI, Italy
| | | | - Paolo Ascenzi
- Laboratorio Interdipartimentale di Microscopia Elettronica, Università Roma Tre, 00146 Roma, Italy.
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3
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C S AK, Das S, Kulbir, Bhardwaj P, Sk MP, Kumar P. Mechanistic insights into nitric oxide oxygenation (NOO) reactions of {CrNO} 5 and {CoNO} 8. Dalton Trans 2023; 52:16492-16499. [PMID: 37874255 DOI: 10.1039/d3dt03177b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Here, we report the nitric oxide oxygenation (NOO) reactions of two distinct metal nitrosyls {Co-nitrosyl (S = 0) vs. Cr-nitrosyl (S = 1/2)}. In this regard, we synthesized and characterized [(BPMEN)Co(NO)]2+ ({CoNO}8, 1) to compare its NOO reaction with that of [(BPMEN)Cr(NO)(Cl-)]+ ({CrNO}5, 2), having a similar ligand framework. Kinetic measurements showed that {CrNO}5 is thermally more stable than {CoNO}8. Complexes 1 and 2, upon reaction with the superoxide anion (O2˙-), generate [(BPMEN)CoII(NO2-)2] (CoII-NO2-, 3) and [(BPMEN)CrIII(NO2-)Cl-]+ (CrIII-NO2-, 4), respectively, with O2 evolution. Furthermore, analysis of these NOO reactions and tracking of the N-atom using 15N-labeled NO (15NO) revealed that the N-atoms of 3 (CoII-15NO2-) and 4 (CrIII-15NO2-) derive from the nitrosyl (15NO) moieties of 1 and 2, respectively. This work represents a comparative study of oxidation reactions of {CoNO}8vs. {CrNO}5, showing different rates of the NOO reactions due to different thermal stability. To complete the NOM cycle, we reacted 3 and 4 with NO, and surprisingly, only 3 generated {CoNO}8 species, while 4 was unreactive towards NO. Furthermore, the phenol ring nitration test, performed using 2,4-di-tert-butylphenol (2,4-DTBP), suggested the presence of a proposed peroxynitrite (PN) intermediate in the NOO reactions of 1 and 2.
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Affiliation(s)
- Akshaya Keerthi C S
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Sandip Das
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Kulbir
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Prabhakar Bhardwaj
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
| | - Md Palashuddin Sk
- Department of Chemistry, Aligarh Muslim University (AMU) Aligarh, Uttar Pradesh 202001, India
| | - Pankaj Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
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Turilli-Ghisolfi ES, Lualdi M, Fasano M. Ligand-Based Regulation of Dynamics and Reactivity of Hemoproteins. Biomolecules 2023; 13:683. [PMID: 37189430 PMCID: PMC10135655 DOI: 10.3390/biom13040683] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 05/17/2023] Open
Abstract
Hemoproteins include several heme-binding proteins with distinct structure and function. The presence of the heme group confers specific reactivity and spectroscopic properties to hemoproteins. In this review, we provide an overview of five families of hemoproteins in terms of dynamics and reactivity. First, we describe how ligands modulate cooperativity and reactivity in globins, such as myoglobin and hemoglobin. Second, we move on to another family of hemoproteins devoted to electron transport, such as cytochromes. Later, we consider heme-based reactivity in hemopexin, the main heme-scavenging protein. Then, we focus on heme-albumin, a chronosteric hemoprotein with peculiar spectroscopic and enzymatic properties. Eventually, we analyze the reactivity and dynamics of the most recently discovered family of hemoproteins, i.e., nitrobindins.
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Affiliation(s)
| | | | - Mauro Fasano
- Department of Science and High Technology, University of Insubria, 22100 Como, Italy
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5
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Nitrosylation of ferric zebrafish nitrobindin: A spectroscopic, kinetic, and thermodynamic study. J Inorg Biochem 2022; 237:111996. [PMID: 36150290 DOI: 10.1016/j.jinorgbio.2022.111996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/30/2022] [Accepted: 09/10/2022] [Indexed: 01/18/2023]
Abstract
Nitrobindins (Nbs) are all-β-barrel heme-proteins present in all the living kingdoms. Nbs inactivate reactive nitrogen species by sequestering NO, converting NO to HNO2, and isomerizing peroxynitrite to NO3- and NO2-. Here, the spectroscopic characterization of ferric Danio rerio Nb (Dr-Nb(III)) and NO scavenging through the reductive nitrosylation of the metal center are reported, both processes being relevant for the regulation of blood flow in fishes through poorly oxygenated tissues, such as retina. Both UV-Vis and resonance Raman spectroscopies indicate that Dr-Nb(III) is a mixture of a six-coordinated aquo- and a five-coordinated species, whose relative abundancies depend on pH. At pH ≤ 7.0, Dr-Nb(III) binds reversibly NO, whereas at pH ≥ 7.8 NO induces the conversion of Dr-Nb(III) to Dr-Nb(II)-NO. The conversion of Dr-Nb(III) to Dr-Nb(II)-NO is a monophasic process, suggesting that the formation of the transient Dr-Nb(III)-NO species is lost in the mixing time of the rapid-mixing stopped-flow apparatus (∼ 1.5 ms). The pseudo-first-order rate constant for the reductive nitrosylation of Dr-Nb(III) is not linearly dependent on the NO concentration but tends to level off. Values of the rate-limiting constant (i.e., klim) increase linearly with the OH- concentration, indicating that the conversion of Dr-Nb(III) to Dr-Nb(II)-NO is limited by the OH--based catalysis. From the dependence of klim on [OH-], the value of the second-order rate constant kOH- was obtained (5.2 × 103 M-1 s-1). Reductive nitrosylation of Dr-Nb(III) leads to the inactivation of two NO molecules: one being converted to HNO2, and the other being tightly bound to the heme-Fe(II) atom.
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6
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De Simone G, Coletta A, di Masi A, Coletta M, Ascenzi P. The Balancing of Peroxynitrite Detoxification between Ferric Heme-Proteins and CO2: The Case of Zebrafish Nitrobindin. Antioxidants (Basel) 2022; 11:antiox11101932. [PMID: 36290653 PMCID: PMC9599043 DOI: 10.3390/antiox11101932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/20/2022] [Accepted: 09/22/2022] [Indexed: 11/16/2022] Open
Abstract
Nitrobindins (Nbs) are all-β-barrel heme proteins and are present in prokaryotes and eukaryotes. Although their function(s) is still obscure, Nbs trap NO and inactivate peroxynitrite. Here, the kinetics of peroxynitrite scavenging by ferric Danio rerio Nb (Dr-Nb(III)) in the absence and presence of CO2 is reported. The Dr-Nb(III)-catalyzed scavenging of peroxynitrite is facilitated by a low pH, indicating that the heme protein interacts preferentially with peroxynitrous acid, leading to the formation of nitrate (~91%) and nitrite (~9%). The physiological levels of CO2 dramatically facilitate the spontaneous decay of peroxynitrite, overwhelming the scavenging activity of Dr-Nb(III). The effect of Dr-Nb(III) on the peroxynitrite-induced nitration of L-tyrosine was also investigated. Dr-Nb(III) inhibits the peroxynitrite-mediated nitration of free L-tyrosine, while, in the presence of CO2, Dr-Nb(III) does not impair nitro-L-tyrosine formation. The comparative analysis of the present results with data reported in the literature indicates that, to act as efficient peroxynitrite scavengers in vivo, i.e., in the presence of physiological levels of CO2, the ferric heme protein concentration must be higher than 10−4 M. Thus, only the circulating ferric hemoglobin levels appear to be high enough to efficiently compete with CO2/HCO3− in peroxynitrite inactivation. The present results are of the utmost importance for tissues, like the eye retina in fish, where blood circulation is critical for adaptation to diving conditions.
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Affiliation(s)
| | - Andrea Coletta
- Dipartimento di Scienze, Università Roma Tre, 00146 Roma, Italy
| | | | - Massimo Coletta
- IRCCS Fondazione Bietti, 00198 Roma, Italy
- Correspondence: (M.C.); (P.A.)
| | - Paolo Ascenzi
- Dipartimento di Scienze, Università Roma Tre, 00146 Roma, Italy
- Correspondence: (M.C.); (P.A.)
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7
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Hydroxylamine-induced oxidation of ferrous nitrobindins. J Biol Inorg Chem 2022; 27:443-453. [PMID: 35543759 DOI: 10.1007/s00775-022-01940-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/21/2022] [Indexed: 12/19/2022]
Abstract
Hemoglobin and myoglobin are generally taken as molecular models of all-α-helical heme-proteins. On the other hand, nitrophorins and nitrobindins (Nb), which are arranged in 8 and 10 β-strands, respectively, represent the molecular models of all-β-barrel heme-proteins. Here, kinetics of the hydroxylamine- (HA-) mediated oxidation of ferrous Mycobacterium tuberculosis, Arabidopsis thaliana, and Homo sapiens nitrobindins (Mt-Nb(II), At-Nb(II), and Hs-Nb(II), respectively), at pH 7.0 and 20.0 °C, are reported. Of note, HA displays antibacterial properties and is a good candidate for the treatment and/or prevention of reactive nitrogen species- (RNS-) linked aging-related pathologies, such as macular degeneration. Under anaerobic conditions, mixing the Mt-Nb(II), At-Nb(II), and Hs-Nb(II) solutions with the HA solutions brings about absorbance spectral changes reflecting the formation of the ferric derivative (i.e., Mt-Nb(III), At-Nb(III), and Hs-Nb(III), respectively). Values of the second order rate constant for the HA-mediated oxidation of Mt-Nb(II), At-Nb(II), and Hs-Nb(II) are 1.1 × 104 M-1 s-1, 6.5 × 104 M-1 s-1, and 2.2 × 104 M-1 s-1, respectively. Moreover, the HA:Nb(II) stoichiometry is 1:2 as reported for ferrous deoxygenated and carbonylated all-α-helical heme-proteins. A comparative look of the HA reduction kinetics by several ferrous heme-proteins suggests that an important role might be played by residues (such as His or Tyr) in the proximity of the heme-Fe atom either coordinating it or not. In this respect, Nbs seem to exploit somewhat different structural aspects, indicating that redox mechanisms for the heme-Fe(II)-to-heme-Fe(III) conversion might differ between all-α-helical and all-β-barrel heme-proteins.
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8
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De Simone G, Sbardella D, Oddone F, Pesce A, Coletta M, Ascenzi P. Structural and (Pseudo-)Enzymatic Properties of Neuroglobin: Its Possible Role in Neuroprotection. Cells 2021; 10:cells10123366. [PMID: 34943874 PMCID: PMC8699588 DOI: 10.3390/cells10123366] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/20/2021] [Accepted: 11/23/2021] [Indexed: 12/17/2022] Open
Abstract
Neuroglobin (Ngb), the third member of the globin family, was discovered in human and murine brains in 2000. This monomeric globin is structurally similar to myoglobin (Mb) and hemoglobin (Hb) α and β subunits, but it hosts a bis-histidyl six-coordinated heme-Fe atom. Therefore, the heme-based reactivity of Ngb is modulated by the dissociation of the distal HisE7-heme-Fe bond, which reflects in turn the redox state of the cell. The high Ngb levels (~100–200 μM) present in the retinal ganglion cell layer and in the optic nerve facilitate the O2 buffer and delivery. In contrast, the very low levels of Ngb (~1 μM) in most tissues and organs support (pseudo-)enzymatic properties including NO/O2 metabolism, peroxynitrite and free radical scavenging, nitrite, hydroxylamine, hydrogen sulfide reduction, and the nitration of aromatic compounds. Here, structural and (pseudo-)enzymatic properties of Ngb, which are at the root of tissue and organ protection, are reviewed, envisaging a possible role in the protection from neuronal degeneration of the retina and the optic nerve.
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Affiliation(s)
- Giovanna De Simone
- Dipartimento di Scienze, Università Roma Tre, Viale Marconi 446, 00146 Roma, Italy;
| | | | | | - Alessandra Pesce
- Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16100 Genova, Italy;
| | - Massimo Coletta
- IRCCS Fondazione Bietti, 00198 Roma, Italy; (D.S.); (F.O.)
- Dipartmento di Scienze Cliniche e Medicina Traslazionale, Università di Roma “Tor Vergata”, Via Montpellier 1, 00133 Roma, Italy
- Correspondence: (M.C.); (P.A.); Tel.: +39-06-72596365 (M.C.); +39-06-57336321 (P.A.)
| | - Paolo Ascenzi
- Dipartimento di Scienze, Università Roma Tre, Viale Marconi 446, 00146 Roma, Italy;
- Accademia Nazionale dei Lincei, Via della Lungara 10, 00165 Roma, Italy
- Unità di Neuroendocrinologia, Metabolismo e Neurofarmacologia, IRCSS Fondazione Santa Lucia, 00179 Roma, Italy
- Correspondence: (M.C.); (P.A.); Tel.: +39-06-72596365 (M.C.); +39-06-57336321 (P.A.)
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9
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De Simone G, di Masi A, Fattibene P, Ciaccio C, Platas-Iglesias C, Coletta M, Pesce A, Ascenzi P. Oxygen-mediated oxidation of ferrous nitrosylated nitrobindins. J Inorg Biochem 2021; 224:111579. [PMID: 34479003 DOI: 10.1016/j.jinorgbio.2021.111579] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 07/23/2021] [Accepted: 08/10/2021] [Indexed: 01/25/2023]
Abstract
The O2-mediated oxidation of all-β-barrel ferrous nitrosylated nitrobindin from Arabidopsis thaliana (At-Nb(II)-NO), Mycobacterium tuberculosis (Mt-Nb(II)-NO), and Homo sapiens (Hs-Nb(II)-NO) to ferric derivative (At-Nb(III), Mt-Nb(III), and Hs-Nb(III), respectively) has been investigated at pH 7.0 and 20.0 °C. Unlike ferrous nitrosylated horse myoglobin, human serum heme-albumin and human hemoglobin, the process in Nb(II)-NO is mono-exponential and linearly dependent on the O2 concentration, displaying a bimolecular behavior, characterized by kon = (6.3 ± 0.8) × 103 M-1 s-1, (1.4 ± 0.2) × 103 M-1 s-1, and (3.9 ± 0.5) × 103 M-1 s-1 for At-Nb(II)-NO, Mt-Nb(II)-NO, and Hs-Nb(II)-NO, respectively. No intermediate is detected, indicating that the O2 reaction with Nb(II)-NO is the rate-limiting step and that the subsequent conversion of the heme-Fe(III)-N(O)OO- species (i.e., N-bound peroxynitrite to heme-Fe(III)) to heme-Fe(III) and NO3- is much faster. A similar mechanism can be invoked for ferrous nitrosylated human neuroglobin and rabbit hemopexin, in which the heme-Fe(III)-N(O)OO- species is formed as well, although the rate-limiting step seems represented by the reshaping of the six-coordinated heme-Fe(III) complex. Although At-Nb(II)-NO and Mt-Nb(II)-NO are partially (while Hs-Nb(II)-NO is almost completely) penta-coordinated, density functional theory (DFT) calculations rule out that the cleavage of the proximal heme-Fe-His bond in Nb(II)-NO is responsible for the more stable heme-Fe(III)-N(O)OO- species. Moreover, the oxidation of the penta-coordinated heme-Fe(II)-NO adduct does not depend on O2 binding at the proximal side of the metal center. These features may instead reflect the peculiarity of Nb folding and of the heme environment, with a reduced steric constraint for the formation of the heme-Fe(III)-N(O)OO- complex.
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Affiliation(s)
- Giovanna De Simone
- Department of Sciences, Roma Tre University, Viale Guglielmo Marconi 446, 00146 Roma, Italy
| | - Alessandra di Masi
- Department of Sciences, Roma Tre University, Viale Guglielmo Marconi 446, 00146 Roma, Italy
| | - Paola Fattibene
- Technical Scientific Service and Core Facilities, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy
| | - Chiara Ciaccio
- Department of Clinical Sciences and Translational Medicine, University of Roma "Tor Vergata", Via Montpellier 1, I-00133 Roma, Italy
| | - Carlos Platas-Iglesias
- Centro de Investigatiòns Cientìficas Avanzadas (CIA), Departamento de Quìmica, Facultade de Ciencias, Universidad da Coruña, 15071 A Coruña, Galicia, Spain
| | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Roma "Tor Vergata", Via Montpellier 1, I-00133 Roma, Italy
| | - Alessandra Pesce
- Department of Physics, University of Genova, Via Dodecaneso 33, 16100 Genova, Italy
| | - Paolo Ascenzi
- Department of Sciences, Roma Tre University, Viale Guglielmo Marconi 446, 00146 Roma, Italy; Interdepartmental Laboratory of Electron Microscopy, Roma Tre University, Via della Vasca Navale 79, I-00146 Roma, Italy.
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10
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Mycobacterial and Human Ferrous Nitrobindins: Spectroscopic and Reactivity Properties. Int J Mol Sci 2021; 22:ijms22041674. [PMID: 33562340 PMCID: PMC7915275 DOI: 10.3390/ijms22041674] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/24/2022] Open
Abstract
Structural and functional properties of ferrous Mycobacterium tuberculosis (Mt-Nb) and human (Hs-Nb) nitrobindins (Nbs) were investigated. At pH 7.0 and 25.0 °C, the unliganded Fe(II) species is penta-coordinated and unlike most other hemoproteins no pH-dependence of its coordination was detected over the pH range between 2.2 and 7.0. Further, despite a very open distal side of the heme pocket (as also indicated by the vanishingly small geminate recombination of CO for both Nbs), which exposes the heme pocket to the bulk solvent, their reactivity toward ligands, such as CO and NO, is significantly slower than in most hemoproteins, envisaging either a proximal barrier for ligand binding and/or crowding of H2O molecules in the distal side of the heme pocket which impairs ligand binding to the heme Fe-atom. On the other hand, liganded species display already at pH 7.0 and 25 °C a severe weakening (in the case of CO) and a cleavage (in the case of NO) of the proximal Fe-His bond, suggesting that the ligand-linked movement of the Fe(II) atom onto the heme plane brings about a marked lengthening of the proximal Fe-imidazole bond, eventually leading to its rupture. This structural evidence is accompanied by a marked enhancement of both ligands dissociation rate constants. As a whole, these data clearly indicate that structural–functional relationships in Nbs strongly differ from what observed in mammalian and truncated hemoproteins, suggesting that Nbs play a functional role clearly distinct from other eukaryotic and prokaryotic hemoproteins.
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NO Scavenging through Reductive Nitrosylation of Ferric Mycobacterium tuberculosis and Homo sapiens Nitrobindins. Int J Mol Sci 2020; 21:ijms21249395. [PMID: 33321752 PMCID: PMC7763097 DOI: 10.3390/ijms21249395] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/24/2020] [Accepted: 12/01/2020] [Indexed: 11/17/2022] Open
Abstract
Ferric nitrobindins (Nbs) selectively bind NO and catalyze the conversion of peroxynitrite to nitrate. In this study, we show that NO scavenging occurs through the reductive nitrosylation of ferric Mycobacterium tuberculosis and Homo sapiens nitrobindins (Mt-Nb(III) and Hs-Nb(III), respectively). The conversion of Mt-Nb(III) and Hs-Nb(III) to Mt-Nb(II)-NO and Hs-Nb(II)-NO, respectively, is a monophasic process, suggesting that over the explored NO concentration range (between 2.5 × 10−5 and 1.0 × 10−3 M), NO binding is lost in the mixing time (i.e., NOkon ≥ 1.0 × 106 M−1 s−1). The pseudo-first-order rate constant for the reductive nitrosylation of Mt-Nb(III) and Hs-Nb(III) (i.e., k) is not linearly dependent on the NO concentration but tends to level off, with a rate-limiting step (i.e., klim) whose values increase linearly with [OH−]. This indicates that the conversion of Mt-Nb(III) and Hs-Nb(III) to Mt-Nb(II)-NO and Hs-Nb(II)-NO, respectively, is limited by the OH−-based catalysis. From the dependence of klim on [OH−], the values of the second-order rate constant kOH− for the reductive nitrosylation of Mt-Nb(III)-NO and Hs-Nb(III)-NO were obtained (4.9 (±0.5) × 103 M−1 s−1 and 6.9 (±0.8) × 103 M−1 s−1, respectively). This process leads to the inactivation of two NO molecules: one being converted to HNO2 and another being tightly bound to the ferrous heme-Fe(II) atom.
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12
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De Simone G, di Masi A, Vita GM, Polticelli F, Pesce A, Nardini M, Bolognesi M, Ciaccio C, Coletta M, Turilli ES, Fasano M, Tognaccini L, Smulevich G, Abbruzzetti S, Viappiani C, Bruno S, Ascenzi P. Mycobacterial and Human Nitrobindins: Structure and Function. Antioxid Redox Signal 2020; 33:229-246. [PMID: 32295384 DOI: 10.1089/ars.2019.7874] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Aims: Nitrobindins (Nbs) are evolutionary conserved all-β-barrel heme-proteins displaying a highly solvent-exposed heme-Fe(III) atom. The physiological role(s) of Nbs is almost unknown. Here, the structural and functional properties of ferric Mycobacterium tuberculosis Nb (Mt-Nb(III)) and ferric Homo sapiens Nb (Hs-Nb(III)) have been investigated and compared with those of ferric Arabidopsis thaliana Nb (At-Nb(III), Rhodnius prolixus nitrophorins (Rp-NP(III)s), and mammalian myoglobins. Results: Data here reported demonstrate that Mt-Nb(III), At-Nb(III), and Hs-Nb(III) share with Rp-NP(III)s the capability to bind selectively nitric oxide, but display a very low reactivity, if any, toward histamine. Data obtained overexpressing Hs-Nb in human embryonic kidney 293 cells indicate that Hs-Nb localizes mainly in the cytoplasm and partially in the nucleus, thanks to a nuclear localization sequence encompassing residues Glu124-Leu154. Human Hs-Nb corresponds to the C-terminal domain of the human nuclear protein THAP4 suggesting that Nb may act as a sensor possibly modulating the THAP4 transcriptional activity residing in the N-terminal region. Finally, we provide strong evidence that both Mt-Nb(III) and Hs-Nb(III) are able to scavenge peroxynitrite and to protect free l-tyrosine against peroxynitrite-mediated nitration. Innovation: Data here reported suggest an evolutionarily conserved function of Nbs related to their role as nitric oxide sensors and components of antioxidant systems. Conclusion: Human THAP4 may act as a sensing protein that couples the heme-based Nb(III) reactivity with gene transcription. Mt-Nb(III) seems to be part of the pool of proteins required to scavenge reactive nitrogen and oxygen species produced by the host during the immunity response.
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Affiliation(s)
| | | | | | - Fabio Polticelli
- Dipartimento di Scienze, Università Roma Tre, Roma, Italy.,Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Roma, Italy
| | | | - Marco Nardini
- Dipartimento di Bioscienze, Università di Milano, Milano, Italy
| | - Martino Bolognesi
- Dipartimento di Bioscienze, Università di Milano, Milano, Italy.,Centro di Ricerche Pediatriche R.E. Invernizzi, Università di Milano, Milano, Italy
| | - Chiara Ciaccio
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, Università di Roma Tor Vergata, Roma, Italy
| | - Massimo Coletta
- Dipartimento di Scienze Cliniche e Medicina Traslazionale, Università di Roma Tor Vergata, Roma, Italy
| | - Emily Samuela Turilli
- Dipartimento di Scienza ed Alta Tecnologia, Università dell'Insubria, Busto Arsizio, Italy
| | - Mauro Fasano
- Dipartimento di Scienza ed Alta Tecnologia, Università dell'Insubria, Busto Arsizio, Italy
| | - Lorenzo Tognaccini
- Dipartimento di Chimica Ugo Schiff, Università di Firenze, Sesto Fiorentino, Italy
| | - Giulietta Smulevich
- Dipartimento di Chimica Ugo Schiff, Università di Firenze, Sesto Fiorentino, Italy
| | - Stefania Abbruzzetti
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, Parma, Italy
| | - Cristiano Viappiani
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, Parma, Italy
| | - Stefano Bruno
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università di Parma, Parma, Italy
| | - Paolo Ascenzi
- Dipartimento di Scienze, Università Roma Tre, Roma, Italy
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13
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Oxygen dissociation from ferrous oxygenated human hemoglobin:haptoglobin complexes confirms that in the R-state α and β chains are functionally heterogeneous. Sci Rep 2019; 9:6780. [PMID: 31043649 PMCID: PMC6494993 DOI: 10.1038/s41598-019-43190-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 04/15/2019] [Indexed: 01/25/2023] Open
Abstract
The adverse effects of extra-erythrocytic hemoglobin (Hb) are counterbalanced by several plasma proteins devoted to facilitate the clearance of free heme and Hb. In particular, haptoglobin (Hp) traps the αβ dimers of Hb, which are delivered to the reticulo-endothelial system by CD163 receptor-mediated endocytosis. Since Hp:Hb complexes show heme-based reactivity, kinetics of O2 dissociation from the ferrous oxygenated human Hp1-1:Hb and Hp2-2:Hb complexes (Hp1-1:Hb(II)-O2 and Hp2-2:Hb(II)-O2, respectively) have been determined. O2 dissociation from Hp1-1:Hb(II)-O2 and Hp2-2:Hb(III)-O2 follows a biphasic process. The relative amplitude of the fast and slow phases ranges between 0.47 and 0.53 of the total amplitude, with values of koff1 (ranging between 25.6 ± 1.4 s-1 and 29.1 ± 1.3 s-1) being about twice faster than those of koff2 (ranging between 13.8 ± 1.6 s-1 and 16.1 ± 1.2 s-1). Values of koff1 and koff2 are essentially the same independently on whether O2 dissociation has been followed after addition of a dithionite solution or after O2 displacement by a CO solution in the presence of dithionite. They correspond to those reported for the dissociation of the first O2 molecule from tetrameric Hb(II)-O2, indicating that in the R-state α and β chains are functionally heterogeneous and the tetramer and the dimer behave identically. Accordingly, the structural conformation of the α and β chains of the Hb dimer bound to Hp corresponds to that of the subunits of the Hb tetramer in the R-state.
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14
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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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15
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De Simone G, di Masi A, Polticelli F, Ascenzi P. Human nitrobindin: the first example of an all-β-barrel ferric heme-protein that catalyzes peroxynitrite detoxification. FEBS Open Bio 2018; 8:2002-2010. [PMID: 30524950 PMCID: PMC6275384 DOI: 10.1002/2211-5463.12534] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 08/29/2018] [Accepted: 09/26/2018] [Indexed: 11/12/2022] Open
Abstract
Nitrobindins (Nbs), constituting a heme‐protein family spanning from bacteria to Homo sapiens, display an all‐β‐barrel structural organization. Human Nb has been described as a domain of the nuclear protein named THAP4, whose physiological function is still unknown. We report the first evidence of the heme‐Fe(III)‐based detoxification of peroxynitrite by the all‐β‐barrel C‐terminal Nb‐like domain of THAP4. Ferric human Nb (Nb(III)) catalyzes the conversion of peroxynitrite to NO3− and impairs the nitration of free l‐tyrosine. The rate of human Nb(III)‐mediated scavenging of peroxynitrite is similar to those of all‐α‐helical horse heart and sperm whale myoglobin and human hemoglobin, generally taken as the prototypes of all‐α‐helical heme‐proteins. The heme‐Fe(III) reactivity of all‐β‐barrel human Nb(III) and all‐α‐helical prototypical heme‐proteins possibly reflects the out‐to‐in‐plane transition of the heme‐Fe(III)‐atom preceding peroxynitrite binding. Human Nb(III) not only catalyzes the detoxification of peroxynitrite but also binds NO, possibly representing a target of reactive nitrogen species.
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Affiliation(s)
| | | | - Fabio Polticelli
- Department of Sciences Roma Tre University Italy.,National Institute of Nuclear Physics Roma Tre Section Italy
| | - Paolo Ascenzi
- Interdepartmental Laboratory for Electron Microscopy Roma Tre University Italy
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16
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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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17
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Ascenzi P, Coletta M. Peroxynitrite Detoxification by Human Haptoglobin:Hemoglobin Complexes: A Comparative Study. J Phys Chem B 2018; 122:11100-11107. [DOI: 10.1021/acs.jpcb.8b05340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Paolo Ascenzi
- Interdepartmental Laboratory for Electron Microscopy, Roma Tre University, Via della Vasca Navale 79, I-00146 Roma, Italy
| | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, Via Montpellier 1, I-00133 Roma, Italy
- Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Via Celso Ulpiani 27, I-70126 Bari, Italy
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18
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Xu W, Fang Y, Ou Z, Chen M, Kadish KM. Synthesis, electrochemical and spectroelectrochemical characterization of iron(III) tetraarylporphyrins containing four β,β′-butano and β,β′-benzo fused rings. J PORPHYR PHTHALOCYA 2018. [DOI: 10.1142/s1088424618500517] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Six iron(III) tetraarylporphyrins containing four [Formula: see text]-butano or [Formula: see text]-benzo fused rings were synthesized and characterized by electrochemistry and spectroelectrochemistry in nonaqueous media. The examined compounds are represented as butano(TpYPP)FeCl and benzo(TpYPP)FeCl, where TpYPP is a dianion of the meso-substituted porphyrin, Y is a CH[Formula: see text], H or Cl substituent on the para-position of the four meso-phenyl rings and butano and benzo are the [Formula: see text]-substituents on each of the four pyrrole rings of the compound. Up to three reductions are observed for each Fe(III) butano- and benzoporphyrin in CH[Formula: see text]Cl[Formula: see text] or pyridine containing 0.1 M TBAP, the first of which is assigned in each case to a metal-centered electron transfer. The second reduction is also metal-centered in CH[Formula: see text]Cl[Formula: see text] and leads to formation of an Fe(I) porphyrin, but it is porphyrin ring-centered and gives an Fe(II) porphyrin [Formula: see text]-anion radical reduction product when pyridine is used as the solvent. The effects of the solvent and type of fused ring system (butano or benzo) on the UV-vis spectra and electrochemical properties of the Fe(III) porphyrins are discussed and comparisons are made to both the structurally related non-[Formula: see text]-substituted iron porphyrins and earlier described butano- or benzotetraarylporphyrins containing Cu(II) or Co(II) central metal ions.
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Affiliation(s)
- Weijie Xu
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Yuanyuan Fang
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Zhongping Ou
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
- Department of Chemistry, University of Houston, Houston, TX 77204-5003, USA
| | - Mingyuan Chen
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
- Department of Chemistry, University of Houston, Houston, TX 77204-5003, USA
| | - Karl M. Kadish
- Department of Chemistry, University of Houston, Houston, TX 77204-5003, USA
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19
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Ascenzi P, De Simone G, Polticelli F, Gioia M, Coletta M. Reductive nitrosylation of ferric human hemoglobin bound to human haptoglobin 1-1 and 2-2. J Biol Inorg Chem 2018; 23:437-445. [PMID: 29605886 DOI: 10.1007/s00775-018-1551-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/09/2018] [Indexed: 12/22/2022]
Abstract
Haptoglobin (Hp) sequesters hemoglobin (Hb) preventing the Hb-based damage occurring upon its physiological release into plasma. Here, reductive nitrosylation of ferric human hemoglobin [Hb(III)] bound to human haptoglobin (Hp) 1-1 and 2-2 [Hp1-1:Hb(III) and Hp2-2:Hb(III), respectively] has been investigated between pH 7.5 and 9.5, at T=20.0 °C. Over the whole pH range explored, only one process is detected reflecting NO binding to Hp1-1:Hb(III) and Hp2-2:Hb(III). Values of the pseudo-first-order rate constant for Hp1-1:Hb(III) and Hp2-2:Hb(III) nitrosylation (k) do not depend linearly on the ligand concentration but tend to level off. The conversion of Hp1-1:Hb(III)-NO to Hp1-1:Hb(II)-NO and of Hp2-2:Hb(III)-NO to Hp2-2:Hb(II)-NO is limited by the OH-- and H2O-based catalysis. In fact, bimolecular NO binding to Hp1-1:Hb(III), Hp2-2:Hb(III), Hp1-1:Hb(II), and Hp2-2:Hb(II) proceeds very rapidly. The analysis of data allowed to determine the values of the dissociation equilibrium constant for Hp1-1:Hb(III) and Hp2-2:Hb(III) nitrosylation [K = (1.2 ± 0.1) × 10-4 M], which is pH-independent, and of the first-order rate constant for Hp1-1:Hb(III) and Hp2-2:Hb(III) conversion to Hp1-1:Hb(II)-NO and Hp2-2:Hb(II)-NO, respectively (k'). From the dependence of k' on [OH-], values of hOH- [(4.9 ± 0.6) × 103 M-1 s-1 and (6.79 ± 0.7) × 103 M-1 s-1, respectively] and of [Formula: see text] [(2.6 ± 0.3) × 10-3 s-1] were determined. Values of kinetic and thermodynamic parameters for Hp1-1:Hb(III) and Hp2-2:Hb(III) reductive nitrosylation match well with those of the Hb R-state, which is typical of the αβ dimers of Hb bound to Hp.
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Affiliation(s)
- Paolo Ascenzi
- Interdepartmental Laboratory of Electron Microscopy, Roma Tre University, Via Della Vasca Navale 79, 00146, Rome, Italy.
| | - Giovanna De Simone
- Department of Sciences, Roma Tre University, Viale Guglielmo Marconi 446, 00146, Rome, Italy
| | - Fabio Polticelli
- Department of Sciences, Roma Tre University, Viale Guglielmo Marconi 446, 00146, Rome, Italy.,Roma Tre Section, National Institute of Nuclear Physics, Via Della Vasca Navale 84, 00146, Rome, Italy
| | - Magda Gioia
- Department of Clinical Sciences and Translational Medicine, University of Roma "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy.,Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Via Celso Ulpiani 27, 70126, Bari, Italy
| | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Roma "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy.,Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Via Celso Ulpiani 27, 70126, Bari, Italy
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20
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De Simone G, Ascenzi P, di Masi A, Polticelli F. Nitrophorins and nitrobindins: structure and function. Biomol Concepts 2018; 8:105-118. [PMID: 28574374 DOI: 10.1515/bmc-2017-0013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 05/03/2017] [Indexed: 12/23/2022] Open
Abstract
Classical all α-helical globins are present in all living organisms and are ordered in three lineages: (i) flavohemoglobins and single domain globins, (ii) protoglobins and globin coupled sensors and (iii) truncated hemoglobins, displaying the 3/3 or the 2/2 all α-helical fold. However, over the last two decades, all β-barrel and mixed α-helical-β-barrel heme-proteins displaying heme-based functional properties (e.g. ligand binding, transport and sensing) closely similar to those of all α-helical globins have been reported. Monomeric nitrophorins (NPs) and α1-microglobulin (α1-m), belonging to the lipocalin superfamily and nitrobindins (Nbs) represent prototypical heme-proteins displaying the all β-barrel and mixed α-helical-β-barrel folds. NPs are confined to the Reduviidae and Cimicidae families of Heteroptera, whereas α1-m and Nbs constitute heme-protein families spanning bacteria to Homo sapiens. The structural organization and the reactivity of the stable ferric solvent-exposed heme-Fe atom suggest that NPs and Nbs are devoted to NO transport, storage and sensing, whereas Hs-α1-m participates in heme metabolism. Here, the structural and functional properties of NPs and Nbs are reviewed in parallel with those of sperm whale myoglobin, which is generally taken as the prototype of monomeric globins.
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21
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Ascenzi P, Bocedi A, Gioia M, Fanali G, Fasano M, Coletta M. Warfarin inhibits allosterically the reductive nitrosylation of ferric human serum heme-albumin. J Inorg Biochem 2017; 177:63-75. [PMID: 28926756 DOI: 10.1016/j.jinorgbio.2017.08.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 08/30/2017] [Indexed: 12/31/2022]
Abstract
Human serum heme-albumin (HSA-heme-Fe) displays heme-based ligand binding and (pseudo-)enzymatic properties. Here, the effect of the prototypical drug warfarin on kinetics and thermodynamics of NO binding to ferric and ferrous HSA-heme-Fe (HSA-heme-Fe(III) and HSA-heme-Fe(II), respectively) and on the NO-mediated reductive nitrosylation of the heme-Fe atom is reported; data were obtained between pH5.5 and 9.5 at 20.0°C. Since warfarin is a common drug, its effect on the reactivity of HSA-heme-Fe represents a relevant issue in the pharmacological therapy management. The inhibition of NO binding to HSA-heme-Fe(III) and HSA-heme-Fe(II) as well as of the NO-mediated reductive nitrosylation of the heme-Fe(III) atom by warfarin has been ascribed to drug binding to the fatty acid binding site 2 (FA2), shifting allosterically the penta-to-six coordination equilibrium of the heme-Fe atom toward the low reactive species showing the six-coordinated metal center by His146 and Tyr161 residues. These data: (i) support the role of HSA-heme-Fe in trapping NO, (ii) highlight the modulation of the heme-Fe-based reactivity by drugs, and (iii) could be relevant for the modulation of HSA functions by drugs in vivo.
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Affiliation(s)
- Paolo Ascenzi
- Interdepartmental Laboratory for Electron Microscopy, Roma Tre University, I-00146 Roma, Italy.
| | - Alessio Bocedi
- Department of Chemical Sciences and Technology, University of Roma "Tor Vergata", I-00133 Roma, Italy
| | - Magda Gioia
- Department of Clinical Sciences and Translational Medicine, University of Roma "Tor Vergata", I-00133 Roma, Italy; Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, I-70126 Bari, Italy
| | | | - Mauro Fasano
- Department of Science and High Technology, University of Insubria, I-21052 Busto Arsizio, VA, Italy; Neuroscience Research Center, University of Insubria, I-21052 Busto Arsizio, VA, 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 the Chemistry of Metals in Biological Systems, I-70126 Bari, Italy
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