1
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Gabler T, Dali A, Bellei M, Sebastiani F, Becucci M, Battistuzzi G, Furtmüller PG, Smulevich G, Hofbauer S. Revisiting catalytic His and Glu residues in coproporphyrin ferrochelatase - unexpected activities of active site variants. FEBS J 2024; 291:2260-2272. [PMID: 38390750 DOI: 10.1111/febs.17101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/17/2024] [Accepted: 02/13/2024] [Indexed: 02/24/2024]
Abstract
The identification of the coproporphyrin-dependent heme biosynthetic pathway, which is used almost exclusively by monoderm bacteria in 2015 by Dailey et al. triggered studies aimed at investigating the enzymes involved in this pathway that were originally assigned to the protoporphyrin-dependent heme biosynthetic pathway. Here, we revisit the active site of coproporphyrin ferrochelatase by a biophysical and biochemical investigation using the physiological substrate coproporphyrin III, which in contrast to the previously used substrate protoporphyrin IX has four propionate substituents and no vinyl groups. In particular, we have compared the reactivity of wild-type coproporphyrin ferrochelatase from the firmicute Listeria monocytogenes with those of variants, namely, His182Ala (H182A) and Glu263Gln (E263Q), involving two key active site residues. Interestingly, both variants are active only toward the physiological substrate coproporphyrin III but inactive toward protoporphyrin IX. In addition, E263 exchange impairs the final oxidation step from ferrous coproheme to ferric coproheme. The characteristics of the active site in the context of the residues involved and the substrate binding properties are discussed here using structural and functional means, providing a further contribution to the deciphering of this enigmatic reaction mechanism.
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Affiliation(s)
- Thomas Gabler
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Andrea Dali
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Sesto Fiorentino, Italy
| | - Marzia Bellei
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
| | - Federico Sebastiani
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Sesto Fiorentino, Italy
| | - Maurizio Becucci
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Sesto Fiorentino, Italy
| | - Gianantonio Battistuzzi
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Paul Georg Furtmüller
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Giulietta Smulevich
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Sesto Fiorentino, Italy
- INSTM Research Unit of Firenze, Sesto Fiorentino, Italy
| | - Stefan Hofbauer
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
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2
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Gabler T, Dali A, Sebastiani F, Furtmüller PG, Becucci M, Hofbauer S, Smulevich G. Iron insertion into coproporphyrin III-ferrochelatase complex: Evidence for an intermediate distorted catalytic species. Protein Sci 2023; 32:e4788. [PMID: 37743577 PMCID: PMC10578119 DOI: 10.1002/pro.4788] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/07/2023] [Accepted: 09/20/2023] [Indexed: 09/26/2023]
Abstract
Understanding the reaction mechanism of enzymes at the molecular level is generally a difficult task, since many parameters affect the turnover. Often, due to high reactivity and formation of transient species or intermediates, detailed information on enzymatic catalysis is obtained by means of model substrates. Whenever possible, it is essential to confirm a reaction mechanism based on substrate analogues or model systems by using the physiological substrates. Here we disclose the ferrous iron incorporation mechanism, in solution, and in crystallo, by the coproporphyrin III-coproporphyrin ferrochelatase complex from the firmicute, pathogen, and antibiotic resistant, Listeria monocytogenes. Coproporphyrin ferrochelatase plays an important physiological role as the metalation represents the penultimate reaction step in the prokaryotic coproporphyrin-dependent heme biosynthetic pathway, yielding coproheme (ferric coproporphyrin III). By following the metal titration with resonance Raman spectroscopy and x-ray crystallography, we prove that upon metalation the saddling distortion becomes predominant both in the crystal and in solution. This is a consequence of the readjustment of hydrogen bond interactions of the propionates with the protein scaffold during the enzymatic catalysis. Once the propionates have established the interactions typical of the coproheme complex, the distortion slowly decreases, to reach the almost planar final product.
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Affiliation(s)
- Thomas Gabler
- Department of ChemistryInstitute of Biochemistry, University of Natural Resources and Life SciencesViennaAustria
| | - Andrea Dali
- Dipartimento di Chimica “Ugo Schiff”—DICUSUniversità di FirenzeSesto FiorentinoItaly
| | - Federico Sebastiani
- Dipartimento di Chimica “Ugo Schiff”—DICUSUniversità di FirenzeSesto FiorentinoItaly
| | - Paul Georg Furtmüller
- Department of ChemistryInstitute of Biochemistry, University of Natural Resources and Life SciencesViennaAustria
| | - Maurizio Becucci
- Dipartimento di Chimica “Ugo Schiff”—DICUSUniversità di FirenzeSesto FiorentinoItaly
| | - Stefan Hofbauer
- Department of ChemistryInstitute of Biochemistry, University of Natural Resources and Life SciencesViennaAustria
| | - Giulietta Smulevich
- Dipartimento di Chimica “Ugo Schiff”—DICUSUniversità di FirenzeSesto FiorentinoItaly
- INSTM Research Unit of FirenzeSesto FiorentinoItaly
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3
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Dali A, Gabler T, Sebastiani F, Destinger A, Furtmüller PG, Pfanzagl V, Becucci M, Smulevich G, Hofbauer S. Active site architecture of coproporphyrin ferrochelatase with its physiological substrate coproporphyrin III: Propionate interactions and porphyrin core deformation. Protein Sci 2023; 32:e4534. [PMID: 36479958 PMCID: PMC9794026 DOI: 10.1002/pro.4534] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/29/2022] [Accepted: 12/03/2022] [Indexed: 12/13/2022]
Abstract
Coproporphyrin ferrochelatases (CpfCs) are enzymes catalyzing the penultimate step in the coproporphyrin-dependent (CPD) heme biosynthesis pathway, which is mainly utilized by monoderm bacteria. Ferrochelatases insert ferrous iron into a porphyrin macrocycle and have been studied for many decades, nevertheless many mechanistic questions remain unanswered to date. Especially CpfCs, which are found in the CPD pathway, are currently in the spotlight of research. This pathway was identified in 2015 and revealed that the correct substrate for these ferrochelatases is coproporphyrin III (cpIII) instead of protoporphyrin IX, as believed prior the discovery of the CPD pathway. The chemistry of cpIII, which has four propionates, differs significantly from protoporphyrin IX, which features two propionate and two vinyl groups. These findings let us to thoroughly describe the physiological cpIII-ferrochelatase complex in solution and in the crystal phase. Here, we present the first crystallographic structure of the CpfC from the representative monoderm pathogen Listeria monocytogenes bound to its physiological substrate, cpIII, together with the in-solution data obtained by resonance Raman and UV-vis spectroscopy, for wild-type ferrochelatase and variants, analyzing propionate interactions. The results allow us to evaluate the porphyrin distortion and provide an in-depth characterization of the catalytically-relevant binding mode of cpIII prior to iron insertion. Our findings are discussed in the light of the observed structural restraints and necessities for this porphyrin-enzyme complex to catalyze the iron insertion process. Knowledge about this initial situation is essential for understanding the preconditions for iron insertion in CpfCs and builds the basis for future studies.
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Affiliation(s)
- Andrea Dali
- Dipartimento di Chimica “Ugo Schiff” – DICUSUniversità di FirenzeSesto Fiorentino (FI)Italy
| | - Thomas Gabler
- Department of ChemistryInstitute of Biochemistry, University of Natural Resources and Life SciencesViennaAustria
| | - Federico Sebastiani
- Dipartimento di Chimica “Ugo Schiff” – DICUSUniversità di FirenzeSesto Fiorentino (FI)Italy
| | - Alina Destinger
- Department of ChemistryInstitute of Biochemistry, University of Natural Resources and Life SciencesViennaAustria
| | - Paul Georg Furtmüller
- Department of ChemistryInstitute of Biochemistry, University of Natural Resources and Life SciencesViennaAustria
| | - Vera Pfanzagl
- Department of ChemistryInstitute of Biochemistry, University of Natural Resources and Life SciencesViennaAustria
| | - Maurizio Becucci
- Dipartimento di Chimica “Ugo Schiff” – DICUSUniversità di FirenzeSesto Fiorentino (FI)Italy
| | - Giulietta Smulevich
- Dipartimento di Chimica “Ugo Schiff” – DICUSUniversità di FirenzeSesto Fiorentino (FI)Italy,INSTM Research Unit of FirenzeSesto Fiorentino (Fi)Italy
| | - Stefan Hofbauer
- Department of ChemistryInstitute of Biochemistry, University of Natural Resources and Life SciencesViennaAustria
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4
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Gabler T, Sebastiani F, Helm J, Dali A, Obinger C, Furtmüller PG, Smulevich G, Hofbauer S. Substrate specificity and complex stability of coproporphyrin ferrochelatase is governed by hydrogen-bonding interactions of the four propionate groups. FEBS J 2021; 289:1680-1699. [PMID: 34719106 DOI: 10.1111/febs.16257] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/19/2021] [Accepted: 10/28/2021] [Indexed: 11/24/2022]
Abstract
Coproporpyhrin III is the substrate of coproporphyrin ferrochelatases (CpfCs). These enzymes catalyse the insertion of ferrous iron into the porphyrin ring. This is the penultimate step within the coproporphyrin-dependent haeme biosynthesis pathway. This pathway was discovered in 2015 and is mainly utilised by monoderm bacteria. Prior to this discovery, monoderm bacteria were believed to utilise the protoporphyrin-dependent pathway, analogously to diderm bacteria, where the substrate for the respective ferrochelatase is protoporphyrin IX, which has two propionate groups at positions 6 and 7 and two vinyl groups at positions 2 and 4. In this work, we describe for the first time the interactions of the four-propionate substrate, coproporphyrin III, and the four-propionate product, iron coproporphyrin III (coproheme), with the CpfC from Listeria monocytogenes and pin down differences with respect to the protoporphyrin IX and haeme b complexes in the wild-type (WT) enzyme. We further created seven LmCpfC variants aiming at altering substrate and product coordination. The WT enzyme and all the variants were comparatively studied by spectroscopic, thermodynamic and kinetic means to investigate in detail the H-bonding interactions, which govern complex stability and substrate specificity. We identified a tyrosine residue (Y124 in LmCpfC), coordinating the propionate at position 2, which is conserved in monoderm CpfCs, to be highly important for binding and stabilisation. Importantly, we also describe a tyrosine-serine-threonine triad, which coordinates the propionate at position 4. The study of the triad variants indicates structural differences between the coproporphyrin III and the coproheme complexes. ENZYME: EC 4.99.1.9.
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Affiliation(s)
- Thomas Gabler
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Federico Sebastiani
- Dipartimento di Chimica 'Ugo Schiff' (DICUS), Università di Firenze, Sesto Fiorentino, Italy
| | - Johannes Helm
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Andrea Dali
- Dipartimento di Chimica 'Ugo Schiff' (DICUS), Università di Firenze, Sesto Fiorentino, Italy
| | - Christian Obinger
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Paul G Furtmüller
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Giulietta Smulevich
- Dipartimento di Chimica 'Ugo Schiff' (DICUS), Università di Firenze, Sesto Fiorentino, Italy.,INSTM Research Unit of Firenze, Sesto Fiorentino, Italy
| | - Stefan Hofbauer
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, Vienna, Austria
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5
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Hofbauer S, Helm J, Obinger C, Djinović-Carugo K, Furtmüller PG. Crystal structures and calorimetry reveal catalytically relevant binding mode of coproporphyrin and coproheme in coproporphyrin ferrochelatase. FEBS J 2020; 287:2779-2796. [PMID: 31794133 PMCID: PMC7340540 DOI: 10.1111/febs.15164] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/18/2019] [Accepted: 12/02/2019] [Indexed: 01/24/2023]
Abstract
Coproporphyrin ferrochelatases (CpfCs, EC 4.99.1.9) insert ferrous iron into coproporphyrin III yielding coproheme. CpfCs are utilized by prokaryotic, mainly monoderm (Gram-positive) bacteria within the recently detected coproporphyrin-dependent (CPD) heme biosynthesis pathway. Here, we present a comprehensive study on CpfC from Listeria monocytogenes (LmCpfC) including the first crystal structure of a coproheme-bound CpfC. Comparison of crystal structures of apo-LmCpfC and coproheme-LmCpfC allowed identification of structural rearrangements and of amino acids involved in tetrapyrrole macrocycle and Fe2+ binding. Differential scanning calorimetry of apo-, coproporphyrin III-, and coproheme-LmCpfC underline the pronounced noncovalent interaction of both coproporphyrin and coproheme with the protein (ΔTm = 11 °C compared to apo-LmCpfC), which includes the propionates (p2, p4, p6, p7) and the amino acids Arg29, Arg45, Tyr46, Ser53, and Tyr124. Furthermore, the thermodynamics and kinetics of coproporphyrin III and coproheme binding to apo-LmCpfC is presented as well as the kinetics of insertion of ferrous iron into coproporphyrin III-LmCpfC that immediately leads to formation of ferric coproheme-LmCpfC (kcat /KM = 4.7 × 105 m-1 ·s-1 ). We compare the crystal structure of coproheme-LmCpfC with available structures of CpfCs with artificial tetrapyrrole macrocycles and discuss our data on substrate binding, iron insertion and substrate release in the context of the CPD heme biosynthesis pathway. ENZYME: EC 4.99.1.9 DATABASE: pdb-codes of structural data in this work: 6RWV, 6SV3.
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Affiliation(s)
- Stefan Hofbauer
- Department of Chemistry, Institute of Biochemistry, BOKU - University of Natural Resources and Life Sciences, Vienna, Austria
| | - Johannes Helm
- Department of Chemistry, Institute of Biochemistry, BOKU - University of Natural Resources and Life Sciences, Vienna, Austria
| | - Christian Obinger
- Department of Chemistry, Institute of Biochemistry, BOKU - University of Natural Resources and Life Sciences, Vienna, Austria
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Austria
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia
| | - Paul G Furtmüller
- Department of Chemistry, Institute of Biochemistry, BOKU - University of Natural Resources and Life Sciences, Vienna, Austria
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6
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Schuelke-Sanchez AE, Stone AA, Liptak MD. CfbA promotes insertion of cobalt and nickel into ruffled tetrapyrroles in vitro. Dalton Trans 2019; 49:1065-1076. [PMID: 31868194 DOI: 10.1039/c9dt03601f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The nickel chelatase CfbA is the smallest member of the chelatase family, but the mechanism by which this enzyme inserts nickel into sirohydrochlorin is unknown. In order to gain mechanistic insight, metal binding, tetrapyrrole binding, and enzyme activity were characterized for a variety of substrates using several spectroscopic and computational approaches. Mass spectrometery and magnetic circular dichroism experiments revealed that CfbA binds an octahedral, high-spin metal substrate. UV/Vis absorption spectroscopy demonstrated that the enzyme binds a wide range of tetrapyrrole substrates and perturbs their electronic structures. Based upon activity assays, CfbA promotes insertion of cobalt and nickel into several tetrapyrroles, including cobalt insertion into protopophyrin IX. Finally, density functional theory models were developed which strongly suggest that observed spectral changes upon binding to the enzyme can be explained by tetrapyrrole ruffling, but not deprotonation or saddling. The observation of an octahedral, high-spin metal bound to CfbA leads to a generalization for all class II chelatases: these enzymes bind labile metal substrates and metal desolvation is not a rate-limiting step. The conclusion that CfbA ruffles its tetrapyrrole substrate reveals that the CfbA mechanism is different from that currently proposed for ferrochelatase, and identifies an intriguing correlation between metal substrate specificity and tetrapyrrole distortion mode in chelatases.
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Affiliation(s)
| | - Alissa A Stone
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, USA.
| | - Matthew D Liptak
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, USA.
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7
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Iordache AM, Cristescu R, Fagadar-Cosma E, Popescu AC, Ciucu AA, Iordache SM, Balan A, Nichita C, Stamatin I, Chrisey DB. Histamine detection using functionalized porphyrin as electrochemical mediator. CR CHIM 2018. [DOI: 10.1016/j.crci.2017.05.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Gorski A, Starukhin A, Stavrov S, Gawinkowski S, Waluk J. Resonance Raman spectroscopy study of protonated porphyrin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 173:350-355. [PMID: 27685003 DOI: 10.1016/j.saa.2016.09.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 09/14/2016] [Accepted: 09/20/2016] [Indexed: 06/06/2023]
Abstract
Resonance Raman microscopy was used to study the resonance Raman scattering of the diacid (diprotonated form) of free-base porphyrin (21H,23H-porphine) in a crystal powder and KBr pellets. Intensive lines in the spectral range between 100÷1000cm-1 have been detected and assigned as spectral manifestation of out-of-plane modes. The Raman spectra were simulated by means of DFT methods and compared with the experimental data. It is evident from experimental and theoretical results that the activation of out-of-plane modes arises from saddle distortion of the porphyrin macrocycle upon formation of its diprotonated form.
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Affiliation(s)
- A Gorski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka, 44/52, 01-224 Warsaw, Poland.
| | - A Starukhin
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka, 44/52, 01-224 Warsaw, Poland; B. I. Stepanov Institute of Physics, National Academy of Science of Belarus, Nezalezhnasti Ave., 70, 220072 Minsk, Belarus
| | - S Stavrov
- Sackler Institute of Molecular Medicine, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - S Gawinkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka, 44/52, 01-224 Warsaw, Poland
| | - J Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka, 44/52, 01-224 Warsaw, Poland; Faculty of Mathematics and Natural Sciences, College of Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
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9
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Castillero P, Roales J, Lopes-Costa T, Sánchez-Valencia JR, Barranco A, González-Elipe AR, Pedrosa JM. Optical Gas Sensing of Ammonia and Amines Based on Protonated Porphyrin/TiO₂ Composite Thin Films. SENSORS 2016; 17:s17010024. [PMID: 28025570 PMCID: PMC5298597 DOI: 10.3390/s17010024] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/14/2016] [Accepted: 12/20/2016] [Indexed: 12/27/2022]
Abstract
Open porous and transparent microcolumnar structures of TiO2 prepared by physical vapour deposition in glancing angle configuration (GLAD-PVD) have been used as host matrices for two different fluorescent cationic porphyrins, 5-(N-methyl 4-pyridyl)-10,15,20-triphenyl porphine chloride (MMPyP) and meso-tetra (N-methyl 4-pyridyl) porphine tetrachloride (TMPyP). The porphyrins have been anchored by electrostatic interactions to the microcolumns by self-assembly through the dip-coating method. These porphyrin/TiO2 composites have been used as gas sensors for ammonia and amines through previous protonation of the porphyrin with HCl followed by subsequent exposure to the basic analyte. UV–vis absorption, emission, and time-resolved spectroscopies have been used to confirm the protonation–deprotonation of the two porphyrins and to follow their spectral changes in the presence of the analytes. The monocationic porphyrin has been found to be more sensible (up to 10 times) than its tetracationic counterpart. This result has been attributed to the different anchoring arrangements of the two porphyrins to the TiO2 surface and their different states of aggregation within the film. Finally, there was an observed decrease of the emission fluorescence intensity in consecutive cycles of exposure and recovery due to the formation of ammonium chloride inside the film.
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Affiliation(s)
- Pedro Castillero
- Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, Américo Vespucio 49, Sevilla 41092, Spain.
| | - Javier Roales
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera Km. 1, Sevilla 41013, Spain.
| | - Tânia Lopes-Costa
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera Km. 1, Sevilla 41013, Spain.
| | - Juan R Sánchez-Valencia
- Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, Américo Vespucio 49, Sevilla 41092, Spain.
| | - Angel Barranco
- Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, Américo Vespucio 49, Sevilla 41092, Spain.
| | - Agustín R González-Elipe
- Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, Américo Vespucio 49, Sevilla 41092, Spain.
| | - José M Pedrosa
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera Km. 1, Sevilla 41013, Spain.
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10
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Diller K, Papageorgiou AC, Klappenberger F, Allegretti F, Barth JV, Auwärter W. In vacuo interfacial tetrapyrrole metallation. Chem Soc Rev 2016; 45:1629-56. [PMID: 26781034 DOI: 10.1039/c5cs00207a] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The metallation of tetrapyrroles at well-defined surfaces under ultra-high vacuum conditions represents an unconventional synthesis approach to achieve tetrapyrrole-based metal-organic complexes and architectures. Different protocols, pioneered over the last decade, and now widely applied in several fields, provide an elegant route to metallo-tetrapyrrole systems often elusive to conventional procedures and give access and exquisite insight into on-surface tetrapyrrole chemistry. As highlighted by the functionality of metallo-porphyrins in biological or other environments and by the eminent role of metallo-phthalocyanines in synthetic materials, the control on the metal centres incorporated into the macrocycle is of utmost importance to achieve tailored properties in tetrapyrrole-based nanosystems. In the on-surface scenario, precise metallation pathways were developed, including reactions of tetrapyrroles with metals supplied by physical vapour deposition, chemical vapour deposition or the tip of a scanning tunnelling microscope, and self-metallation by atoms of an underlying support. Herein, we provide a comprehensive overview of in vacuo tetrapyrrole metallation, addressing two-dimensional as well as three-dimensional systems. Furthermore, we comparatively assess the available library of on-surface metallation protocols and elaborate on the state-of-the-art methodology.
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Affiliation(s)
- Katharina Diller
- Physik-Department E20, Technische Universität München (TUM), James-Franck-Str. 1, 85748 Garching, Germany. and Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland.
| | - Anthoula C Papageorgiou
- Physik-Department E20, Technische Universität München (TUM), James-Franck-Str. 1, 85748 Garching, Germany.
| | - Florian Klappenberger
- Physik-Department E20, Technische Universität München (TUM), James-Franck-Str. 1, 85748 Garching, Germany.
| | - Francesco Allegretti
- Physik-Department E20, Technische Universität München (TUM), James-Franck-Str. 1, 85748 Garching, Germany.
| | - Johannes V Barth
- Physik-Department E20, Technische Universität München (TUM), James-Franck-Str. 1, 85748 Garching, Germany.
| | - Willi Auwärter
- Physik-Department E20, Technische Universität München (TUM), James-Franck-Str. 1, 85748 Garching, Germany.
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11
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Hunter GA, Vankayala SL, Gillam ME, Kearns FL, Lee Woodcock H, Ferreira GC. The conserved active site histidine-glutamate pair of ferrochelatase coordinately catalyzes porphyrin metalation. J PORPHYR PHTHALOCYA 2016. [DOI: 10.1142/s1088424616500395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Ferrochelatase catalyzes the insertion of ferrous iron into protoporphyrin IX to generate heme. Despite recent research on the reaction mechanism of ferrochelatase, the precise roles and localization of individual active site residues in catalysis, particularly those involved in the insertion of the ferrous iron into the protoporphyrin IX substrate, remain controversial. One outstanding question is from which side of the macrocycle of the bound porphyin substrate is the ferrous iron substrate inserted. Pre-steady state kinetic experiments done under single-turnover conditions conclusively demonstrate that metal ion insertion is pH-dependent, and that the conserved active site His-Glu pair coordinately catalyzes the metal ion insertion reaction. Further, p[Formula: see text] calculations and molecular dynamic simulations indicate that the active site His is deprotonated and the protonation state of the Glu relates to the conformational state of ferrochelatase. Specifically, the conserved Glu in the open conformation of ferrochelatase is deprotonated, while it remains protonated in the closed conformation. These findings support not only the role of the His-Glu pair in catalyzing metal ion insertion, as these residues need to be deprotonated to bind the incoming metal ion, but also the importance of the relationship between the protonation state of the Glu residue and the conformation of ferrochelatase. Finally, the results of this study are consistent with our previous proposal that the unwinding of the [Formula: see text]-helix, the major structural determinant of the closed to open conformational transition in ferrochelatase, is associated with the Glu residue binding the Fe[Formula: see text] substrate from a mitochondrial Fe[Formula: see text] donor.
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Affiliation(s)
- Gregory A. Hunter
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33620, USA
| | | | - Mallory E. Gillam
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33620, USA
| | - Fiona L. Kearns
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
| | - H. Lee Woodcock
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
| | - Gloria C. Ferreira
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33620, USA
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
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