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Lipid Liquid Crystal Nanoparticles: Promising Photosensitizer Carriers for the Treatment of Infected Cutaneous Wounds. Pharmaceutics 2023; 15:pharmaceutics15020305. [PMID: 36839628 PMCID: PMC9964009 DOI: 10.3390/pharmaceutics15020305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 01/18/2023] Open
Abstract
Cutaneous chronic wounds impose a silent pandemic that affects the lives of millions worldwide. The delayed healing process is usually complicated by opportunistic bacteria that infect wounds. Staphylococcus aureus is one of the most prevalent bacteria in infected cutaneous wounds, with the ability to form antibiotic-resistant biofilms. Recently, we have demonstrated the potential of gallium protoporphyrin lipid liquid crystalline nanoparticles (GaPP-LCNP) as a photosensitizer against S. aureus biofilms in vitro. Herein, we investigate the potential of GaPP-LCNP using a pre-clinical model of infected cutaneous wounds. GaPP-LCNP showed superior antibacterial activity compared to unformulated GaPP, reducing biofilm bacterial viability by 5.5 log10 compared to 2.5 log10 in an ex vivo model, and reducing bacterial viability by 1 log10 in vivo, while unformulated GaPP failed to reduce bacterial burden. Furthermore, GaPP-LCNP significantly promoted wound healing through reduction in the bacterial burden and improved early collagen deposition. These findings pave the way for future pre-clinical investigation and treatment optimizations to translate GaPP-LCNP towards clinical application.
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2
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Awad M, Barnes TJ, Thomas N, Joyce P, Prestidge CA. Gallium Protoporphyrin Liquid Crystalline Lipid Nanoparticles: A Third-Generation Photosensitizer against Pseudomonas aeruginosa Biofilms. Pharmaceutics 2022; 14:pharmaceutics14102124. [PMID: 36297559 PMCID: PMC9610264 DOI: 10.3390/pharmaceutics14102124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 11/07/2022] Open
Abstract
The looming antimicrobial resistance pandemic has encouraged the investigation of antimicrobial photodynamic therapy (aPDT) as a promising technology to combat recalcitrant bacterial infections caused by antibiotic resistant strains. Here, we report on the optimization and effective application of gallium protoporphyrin liquid crystalline lipid nanoparticles (GaPP-LCNP) as a photosensitizer for aPDT against the Gram-negative bacteria P. aeruginosa in both planktonic and biofilm modes of growth. LCNP significantly enhanced the performance of GaPP as photosensitizer by two-fold, which was correlated with higher antibacterial activity, reducing the viability of planktonic P. aeruginosa by 7 log10 using 0.8 µM GaPP-LCNP and a light dose of 17 J.cm−2. Importantly, GaPP-LCNP also reduced the viability of biofilms by 6 log10 at relatively low light dose of 34.2 J.cm−2 using only 3 µM GaPP-LCNP. The high antibiofilm activity of GaPP-LCNP at low GaPP-LCNP dose indicated the high efficiency and safety profile of GaPP-LCNP as a promising platform for photodynamic inactivation of recalcitrant infections.
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Affiliation(s)
- Muhammed Awad
- Centre for Pharmaceutical Innovation, University of South Australia, Clinical and Health Sciences, Adelaide 5000, Australia
- Basil Hetzel Institute for Translational Health Research, Woodville 5011, Australia
| | - Timothy J. Barnes
- Centre for Pharmaceutical Innovation, University of South Australia, Clinical and Health Sciences, Adelaide 5000, Australia
| | - Nicky Thomas
- Centre for Pharmaceutical Innovation, University of South Australia, Clinical and Health Sciences, Adelaide 5000, Australia
| | - Paul Joyce
- Centre for Pharmaceutical Innovation, University of South Australia, Clinical and Health Sciences, Adelaide 5000, Australia
| | - Clive A. Prestidge
- Centre for Pharmaceutical Innovation, University of South Australia, Clinical and Health Sciences, Adelaide 5000, Australia
- Correspondence:
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3
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Yuan D, Yu H, Liu S, Hao L, Zhang J. Prediction and Experimental Verification of a Hierarchical Transcription Factor Regulatory Network of Porcine Myoglobin (Mb). Animals (Basel) 2021; 11:ani11123599. [PMID: 34944373 PMCID: PMC8698129 DOI: 10.3390/ani11123599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 11/16/2022] Open
Abstract
Myoglobin is a key chemical component that determines meat's color and affects consumers' purchase intentions. In this work, we firstly identified the promoter sequence of the Mb gene from the primary assembly of high-throughput genome sequencing in pigs, and predicted its potential transcription factors by LASAGNA. Through the data mining of the mRNA expression profile of longissimus dorsi muscle of different pig breeds, we constructed a hierarchical interplay network of Mb-TFs (Myoglobin-Transcription Factors), consisting of 16 adaptive transcription factors and 23 secondary transcription factors. The verification of gene expression in longissimus dorsi muscle showed that the Mb mRNA and encoded protein were significantly (p < 0.05) more abundant in Bama pigs than Yorkshire pigs. The qRT-PCR (Real-Time Quantitative Reverse Transcription PCR) validation on genes of the Mb-TFs network showed that FOS, STAT3, STAT1, NEFL21, NFE2L2 and MAFB were significant positive regulatory core transcription factors of Mb-TFs network in Bama pigs, whereas ATF3 was the secondary transcription factor most responsible for the activation of the above transcription factors. Our study provides a new strategy to unravel the mechanism of pork color formation, based on public transcriptome and genome data analysis.
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Munro OQ, Coutsolelos AG, Cheng B, Robert Scheidt W. Single hydroxo-bridged group 13 metalloporphyrin dimers: Solution studies and solid-state structures. J PORPHYR PHTHALOCYA 2019. [DOI: 10.1142/s1088424619500834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The syntheses of indium, gallium and aluminum porphyrin dimers with a single hydroxo-bridge, [Formula: see text][M(Porph)]2(OH)[Formula: see text], are described. Emphasis is given to indium and gallium derivatives. The X-ray structures for [Formula: see text] [Ga(OEP)]2(OH)[Formula: see text] ClO4 and [Formula: see text] [In(OEP)]2(OH)[Formula: see text] ClO4 (two forms) are presented. The dimeric molecules can be synthesized by the acid-treatment of the corresponding hydroxo-ligated monomeric complexes [M(OEP)(OH)] and [M(TPP)(OH)]. The nature of the starting material (the hydroxo-ligated monomer) was first suggested by IR spectroscopy and further proved by proton-deuterium exchange followed by 1H NMR spectroscopy. The structure of a monomeric indium hydroxide complex, [In(OEP)(OH)], is also presented. The synthesis of the dimer for all metals can be monitored by UV-vis spectroscopy, which clearly demonstrates that a blue-shift of the Soret band accompanies formation of the dimer from the monomer. A strong [Formula: see text]–[Formula: see text]interaction between the two porphyrin rings of these [Formula: see text]-hydroxo-bridged dimers is confirmed both by solution state studies (1H NMR and UV-vis spectroscopy) and the X-ray structures of [Formula: see text] [M(OEP)]2(OH)[Formula: see text] ClO4 (M = In, Ga). In addition, exposure of methylene chloride solutions of these bridged complexes to white light afforded the corresponding chloro derivatives, [M(Porph)Cl]. The stereochemistry of a range of [Formula: see text]-hydroxo dimers is discussed and DFT simulations at the HSEH1PBE/SDD level of theory provide suitable structural models and further electronic structure insights on selected [Ga(Porph)(OH)] and [Formula: see text] [Ga(Porph)]2(OH)[Formula: see text][Formula: see text] derivatives.
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Affiliation(s)
- Orde Q. Munro
- School of Chemistry, University of the Witwatersrand, Johannesburg, PO WITS 2050, South Africa
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Athanassios G. Coutsolelos
- Department of Chemistry, University of Crete, Voutes Campus, 70013 Heraklion-Crete, Greece
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Beisong Cheng
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - W. Robert Scheidt
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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5
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Yadav R, Scott EE. Endogenous insertion of non-native metalloporphyrins into human membrane cytochrome P450 enzymes. J Biol Chem 2018; 293:16623-16634. [PMID: 30217815 DOI: 10.1074/jbc.ra118.005417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/13/2018] [Indexed: 11/06/2022] Open
Abstract
Human cytochrome P450 enzymes are membrane-bound heme-containing monooxygenases. As is the case for many heme-containing enzymes, substitution of the metal in the center of the heme can be useful for mechanistic and structural studies of P450 enzymes. For many heme proteins, the iron protoporphyrin prosthetic group can be extracted and replaced with protoporphyrin containing another metal, but human membrane P450 enzymes are not stable enough for this approach. The method reported herein was developed to endogenously produce human membrane P450 proteins with a nonnative metal in the heme. This approach involved coexpression of the P450 of interest, a heme uptake system, and a chaperone in Escherichia coli growing in iron-depleted minimal medium supplemented with the desired trans-metallated protoporphyrin. Using the steroidogenic P450 enzymes CYP17A1 and CYP21A2 and the drug-metabolizing CYP3A4, we demonstrate that this approach can be used with several human P450 enzymes and several different metals, resulting in fully folded proteins appropriate for mechanistic, functional, and structural studies including solution NMR.
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Affiliation(s)
- Rahul Yadav
- From the Departments of Medicinal Chemistry and
| | - Emily E Scott
- From the Departments of Medicinal Chemistry and .,Pharmacology, University of Michigan, Ann Arbor, Michigan 48109
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6
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Xu S, Kaltashov IA. Evaluation of Gallium as a Tracer of Exogenous Hemoglobin-Haptoglobin Complexes for Targeted Drug Delivery Applications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:2025-2032. [PMID: 27619921 DOI: 10.1007/s13361-016-1484-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 08/15/2016] [Accepted: 08/16/2016] [Indexed: 06/06/2023]
Abstract
Haptoglobin (Hp) is a plasma glycoprotein that generates significant interest in the drug delivery community because of its potential for delivery of antiretroviral medicines with high selectivity to macrophages and monocytes, the latent reservoirs of human immunodeficiency virus. As is the case with other therapies that exploit transport networks for targeted drug delivery, the success of the design and optimization of Hp-based therapies will critically depend on the ability to accurately localize and quantitate Hp-drug conjugates on the varying and unpredictable background of endogenous proteins having identical structure. In this work, we introduce a new strategy for detecting and quantitating exogenous Hp and Hp-based drugs with high sensitivity in complex biological samples using gallium as a tracer of this protein and inductively coupled plasma mass spectrometry (ICP MS) as a method of detection. Metal label is introduced by reconstituting hemoglobin (Hb) with gallium(III)-protoporphyrin IX followed by its complexation with Hp. Formation of the Hp/Hb assembly and its stability are evaluated with native electrospray ionization mass spectrometry. Both stable isotopes of Ga give rise to an abundant signal in ICP MS of a human plasma sample spiked with the metal-labeled Hp/Hb complex. The metal label signal exceeds the spectral interferences' contributions by more than an order of magnitude even with the concentration of the exogenous protein below 10 nM, the level that is more than adequate for the planned pharmacokinetic studies of Hp-based therapeutics. Graphical Abstract ᅟ.
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Affiliation(s)
- Shengsheng Xu
- Department of Chemistry, University of Massachusetts, Amherst, MA, 01003, USA
| | - Igor A Kaltashov
- Department of Chemistry, University of Massachusetts, Amherst, MA, 01003, USA.
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7
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Zhang H, Choi J, Ramani A, Voiry D, Natoli SN, Chhowalla M, McMillin DR, Choi JH. Engineering Chemically Exfoliated Large-Area Two-Dimensional MoS2Nanolayers with Porphyrins for Improved Light Harvesting. Chemphyschem 2016; 17:2854-62. [PMID: 27304393 DOI: 10.1002/cphc.201600511] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Hanyu Zhang
- School of Mechanical Engineering; Purdue University; West Lafayette IN 47907 USA
| | - Jungwook Choi
- School of Mechanical Engineering; Yeungnam University; Gyeongsan 38541 Republic of Korea
| | - Arjun Ramani
- School of Mechanical Engineering; Purdue University; West Lafayette IN 47907 USA
| | - Damien Voiry
- Materials Science and Engineering; Rutgers University; Piscataway NJ 08854 USA
| | - Sean N. Natoli
- Department of Chemistry; Purdue University; West Lafayette IN 47907 USA
| | - Manish Chhowalla
- Materials Science and Engineering; Rutgers University; Piscataway NJ 08854 USA
| | - David R. McMillin
- Department of Chemistry; Purdue University; West Lafayette IN 47907 USA
| | - Jong Hyun Choi
- School of Mechanical Engineering; Purdue University; West Lafayette IN 47907 USA
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8
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de Visser SP, Stillman MJ. Challenging Density Functional Theory Calculations with Hemes and Porphyrins. Int J Mol Sci 2016; 17:519. [PMID: 27070578 PMCID: PMC4848975 DOI: 10.3390/ijms17040519] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 01/09/2023] Open
Abstract
In this paper we review recent advances in computational chemistry and specifically focus on the chemical description of heme proteins and synthetic porphyrins that act as both mimics of natural processes and technological uses. These are challenging biochemical systems involved in electron transfer as well as biocatalysis processes. In recent years computational tools have improved considerably and now can reproduce experimental spectroscopic and reactivity studies within a reasonable error margin (several kcal·mol(-1)). This paper gives recent examples from our groups, where we investigated heme and synthetic metal-porphyrin systems. The four case studies highlight how computational modelling can correctly reproduce experimental product distributions, predicted reactivity trends and guide interpretation of electronic structures of complex systems. The case studies focus on the calculations of a variety of spectroscopic features of porphyrins and show how computational modelling gives important insight that explains the experimental spectra and can lead to the design of porphyrins with tuned properties.
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Affiliation(s)
- Sam P de Visser
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, the University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
| | - Martin J Stillman
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada.
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9
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Brewitz HH, Kühl T, Goradia N, Galler K, Popp J, Neugebauer U, Ohlenschläger O, Imhof D. Role of the Chemical Environment beyond the Coordination Site: Structural Insight into Fe(III) Protoporphyrin Binding to Cysteine-Based Heme-Regulatory Protein Motifs. Chembiochem 2015; 16:2216-24. [PMID: 26260099 DOI: 10.1002/cbic.201500331] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Indexed: 12/17/2022]
Abstract
The importance of heme as a transient regulatory molecule has become a major focus in biochemical research. However, detailed information about the molecular basis of transient heme-protein interactions is still missing. We report an in-depth structural analysis of Fe(III) heme-peptide complexes by a combination of UV/Vis, resonance Raman, and 2D-NMR spectroscopic methods. The experiments reveal insights both into the coordination to the central iron ion and into the spatial arrangement of the amino acid sequences interacting with protoporphyrin IX. Cysteine-based peptides display different heme-binding behavior as a result of the existence of ordered, partially ordered, and disordered conformations in the heme-unbound state. Thus, the heme-binding mode is clearly the consequence of the nature and flexibility of the residues surrounding the iron ion coordinating cysteine. Our analysis reveals scenarios for transient binding of heme to heme-regulatory motifs in proteins and demonstrates that a thorough structural analysis is required to unravel how heme alters the structure and function of a particular protein.
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Affiliation(s)
- Hans Henning Brewitz
- Department of Pharmaceutical Chemistry I, Pharmaceutical Institute, University of Bonn, Brühler Strasse 7, 53119, Bonn, Germany
| | - Toni Kühl
- Centre National de la Recherche Scientifique (CNRS), Laboratoire BIP-UMR 7281, 31, chemin Joseph Aiguier, Batiment IM, 13009, Marseille, France
| | - Nishit Goradia
- Biomolecular NMR Spectroscopy, Leibniz Institute for Age Research-Fritz Lipmann Institute, Beutenbergstrasse 11, 07745, Jena, Germany
| | - Kerstin Galler
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Erlanger Allee 101, 07747, Jena, Germany.,Leibniz Institute of Photonic Technology, Albert-Einstein-Strasse 9, 07745, Jena, Germany
| | - Jürgen Popp
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Erlanger Allee 101, 07747, Jena, Germany.,Leibniz Institute of Photonic Technology, Albert-Einstein-Strasse 9, 07745, Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Ute Neugebauer
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Erlanger Allee 101, 07747, Jena, Germany.,Leibniz Institute of Photonic Technology, Albert-Einstein-Strasse 9, 07745, Jena, Germany
| | - Oliver Ohlenschläger
- Biomolecular NMR Spectroscopy, Leibniz Institute for Age Research-Fritz Lipmann Institute, Beutenbergstrasse 11, 07745, Jena, Germany
| | - Diana Imhof
- Department of Pharmaceutical Chemistry I, Pharmaceutical Institute, University of Bonn, Brühler Strasse 7, 53119, Bonn, Germany.
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10
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He C, Howes BD, Smulevich G, Rumpel S, Reijerse EJ, Lubitz W, Cox N, Knipp M. Nitrite Dismutase Reaction Mechanism: Kinetic and Spectroscopic Investigation of the Interaction between Nitrophorin and Nitrite. J Am Chem Soc 2015; 137:4141-50. [DOI: 10.1021/ja512938u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Chunmao He
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Barry D. Howes
- Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3-13, I-50019 Sesto Fiorentino(Fi), Italy
| | - Giulietta Smulevich
- Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3-13, I-50019 Sesto Fiorentino(Fi), Italy
| | - Sigrun Rumpel
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Edward J. Reijerse
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Nicholas Cox
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Markus Knipp
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
- Faculty
of Chemistry and Biochemistry, Ruhr University, Universitätsstrasse 150, D-44780 Bochum, Germany
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11
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Vu NT, Moriwaki Y, Caaveiro JMM, Terada T, Tsutsumi H, Hamachi I, Shimizu K, Tsumoto K. Selective binding of antimicrobial porphyrins to the heme-receptor IsdH-NEAT3 of Staphylococcus aureus. Protein Sci 2013; 22:942-53. [PMID: 23649633 DOI: 10.1002/pro.2276] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/24/2013] [Accepted: 04/25/2013] [Indexed: 12/20/2022]
Abstract
The Isd (iron-regulated surface determinant) system of the human pathogen Staphylococcus aureus is responsible for the acquisition of heme from the host organism. We recently reported that the extracellular heme receptor IsdH-NEAT3 captures and transfers noniron antimicrobial porphyrins containing metals in oxidation state (III). However, it is unclear if geometric factors such as the size of the metal (ionic radius) affect binding and transfer of metalloporphyrins. We carried out an ample structural, functional, and thermodynamic analysis of the binding properties of antimicrobial indium(III)-porphyrin, which bears a much larger metal ion than the iron(III) of the natural ligand heme. The results demonstrate that the NEAT3 receptor recognizes the In(III)-containing PPIX in a manner very similar to that of heme. Site-directed mutagenesis identifies Tyr642 as the central element in the recognition mechanism as suggested from the crystal structures. Importantly, the NEAT3 receptor possesses the remarkable ability to capture dimers of metalloporphyrin. Molecular dynamics simulations reveal that IsdH-NEAT3 does not require conformational changes, or large rearrangements of the residues within its binding site, to accommodate the much larger (heme)2 ligand. We discuss the implications of these findings for the design of potent inhibitors against this family of key receptors of S. aureus.
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Affiliation(s)
- Nhuan T Vu
- Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
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12
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Wójtowicz H, Bielecki M, Wojaczyński J, Olczak M, Smalley JW, Olczak T. The Porphyromonas gingivalis HmuY haemophore binds gallium(iii), zinc(ii), cobalt(iii), manganese(iii), nickel(ii), and copper(ii) protoporphyrin IX but in a manner different to iron(iii) protoporphyrin IX. Metallomics 2013; 5:343-51. [DOI: 10.1039/c3mt20215a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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14
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Bohle DS, Dodd EL, Pinter TBJ, Stillman MJ. Soluble diamagnetic model for malaria pigment: coordination chemistry of gallium(III)protoporphyrin-IX. Inorg Chem 2012; 51:10747-61. [PMID: 23030718 DOI: 10.1021/ic301106g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The facile axial ligand exchange properties of gallium(III) protoporphyrin IX in methanol solution were utilized to explore self-association interactions by NMR techniques. Structural changes were observed, as well as competitive behavior with the ligands acetate and fluoride, which differed from that seen with the synthetic analogue gallium(III) octaethylporphyrin which lacks acid groups in its side-chains and has less solution heterogeneity as indicated by absorption and MCD spectroscopies. The propionic acid side chains of protoporphyrin IX are implicated in all such interactions of PPIX, and both dynamic metal-propionic interactions and the formation of propionate-bridged dimers are observed. Fluoride coordination provides an unusual example of slow ligand exchange, and this allows for the identification of a fluoride bridged dimer in solution. An improved synthesis of the chloride and hydroxide complexes of gallium(III) protoporphyrin IX is reported. An insoluble gallium analogue of hematin anhydride is described. In general, the interactions between solvent and the metal are found to confer very high solubility, making [Ga(PPIX)](+) a useful model for ferric heme species.
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Affiliation(s)
- D Scott Bohle
- Department of Chemistry, McGill University, Montreal, Quebec, Canada.
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15
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Kuter D, Venter GA, Naidoo KJ, Egan TJ. Experimental and time-dependent density functional theory characterization of the UV-visible spectra of monomeric and μ-oxo dimeric ferriprotoporphyrin IX. Inorg Chem 2012; 51:10233-50. [PMID: 22963249 DOI: 10.1021/ic301154e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Speciation of ferriprotoporphyrin IX, Fe(III)PPIX, in aqueous solution is complex. Despite the use of its characteristic spectroscopic features for identification, the theoretical basis of the unique UV-visible absorbance spectrum of μ-[Fe(III)PPIX](2)O has not been explored. To investigate this and to establish a structural and spectroscopic model for Fe(III)PPIX species, density functional theory (DFT) calculations were undertaken for H(2)O-Fe(III)PPIX and μ-[Fe(III)PPIX](2)O. The models agreed with related Fe(III)porphyrin crystal structures and reproduced vibrational spectra well. The UV-visible absorbance spectra of H(2)O-Fe(III)PPIX and μ-[Fe(III)PPIX](2)O were calculated using time-dependent DFT and reproduced major features of the experimental spectra of both. Transitions contributing to calculated excitations have been identified. The features of the electronic spectrum calculated for μ-[Fe(III)PPIX](2)O were attributed to delocalization of electron density between the two porphyrin rings of the dimer, the weaker ligand field of the axial ligand, and antiferromagnetic coupling of the Fe(III) centers. Room temperature magnetic circular dichroism (MCD) spectra have been recorded and are shown to be useful in distinguishing between these two Fe(III)PPIX species. Bands underlying major spectroscopic features were identified through simultaneous deconvolution of UV-visible and MCD spectra. Computed UV-visible spectra were compared to deconvoluted spectra. Interpretation of the prominent bands of H(2)O-Fe(III)PPIX largely conforms to previous literature. Owing to the weak paramagnetism of μ-[Fe(III)PPIX](2)O at room temperature and the larger number of underlying excitations, interpretation of its experimental UV-visible spectrum was necessarily tentative. Nonetheless, comparison with the calculated spectra of antiferromagnetically coupled and paramagnetic forms of the μ-oxo dimer of Fe(III)porphine suggested that the composition of the Soret band involves a mixture of π→π* and π→d(π) charge transfer transitions. The Q-band and charge transfer bands appear to amalgamate into a mixed low energy envelope consisting of excitations with heavily admixed π→π* and charge transfer transitions.
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Affiliation(s)
- David Kuter
- Department of Chemistry, Department of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701 South Africa
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16
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Tiedemann MT, Pinter TBJ, Stillman MJ. Insight into blocking heme transfer by exploiting molecular interactions in the core Isd heme transporters IsdA-NEAT, IsdC-NEAT, and IsdE of Staphylococcus aureus. Metallomics 2012; 4:751-60. [PMID: 22786442 DOI: 10.1039/c2mt20067h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The pathogenic bacterium Staphylococcus aureus has adopted specialized mechanisms for scavenging iron from its host. The nine cell wall and membrane-associated iron regulated surface determinant (Isd) proteins (IsdH, IsdB, IsdA, IsdC, IsdDEF, IsdG and IsdI) allow Staphylococcus aureus to scavenge iron from the heme in hemoglobin and haptoglobin-hemoglobin. Of these, it is IsdE that chaperones the heme to the ATP binding cassette-type transmembrane transporter (IsdF). IsdH, IsdB, IsdA and IsdC contain at least one heme binding Near Transporter (NEAT) domain. Previous studies have shown that ferric heme is transferred unidirectionally in the sequence IsdA-NEAT (Tyr - proximal amino acid) → IsdC-NEAT (Tyr) → IsdE (His). IsdA-NEAT does not transfer heme directly to IsdE. In this paper we investigated PPIX transfer through the core cell wall proteins of the Isd system (IsdA-NEAT, IsdC-NEAT and IsdE) with FePPIX-dimethylester, and the metal substituted CoPPIX and MnPPIX using ESI-MS, UV-visible absorption and MCD spectroscopy. IsdA binds each of the rings but the subsequent transfer properties to IsdC-N or IsdE are not the same as found with heme. FePPIX-DME transfers from IsdA-N to IsdC-N but neither protein transfers the ring to IsdE. IsdA-N does not transfer CoPPIX to IsdC-N or IsdE. IsdA-N does transfer MnPPIX to both IsdC-N and IsdE. Significantly, it is possible that since CoPPIX and FePPIX-DME bind to IsdA-N, the lack of transfer to IsdC-N and subsequently to IsdE for CoPPIX could prove to be used as a potential disruption agent to the S. aureus heme transfer system and may identify a possible anti-microbial.
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Affiliation(s)
- Michael T Tiedemann
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada
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