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Bedran ZV, Zhukov SS, Abramov PA, Tyurenkov IO, Gorshunov BP, Mostert AB, Motovilov KA. Water-Activated Semiquinone Formation and Carboxylic Acid Dissociation in Melanin Revealed by Infrared Spectroscopy. Polymers (Basel) 2021; 13:4403. [PMID: 34960952 PMCID: PMC8705668 DOI: 10.3390/polym13244403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/29/2021] [Accepted: 12/09/2021] [Indexed: 01/22/2023] Open
Abstract
Eumelanin is a widespread biomacromolecule pigment in the biosphere and has been widely investigated for numerous bioelectronics and energetic applications. Many of these applications depend on eumelanin's ability to conduct proton current at various levels of hydration. The origin of this behavior is connected to a comproportionation reaction between oxidized and reduced monomer moieties and water. A hydration-dependent FTIR spectroscopic study on eumelanin is presented herein, which allows for the first time tracking the comproportionation reaction via the gradual increase of the overall aromaticity of melanin monomers in the course of hydration. We identified spectral features associated with the presence of specific "one and a half" C𝌁O bonds, typical for o-semiquinones. Signatures of semiquinone monomers with internal hydrogen bonds and that carboxylic groups, in contrast to semiquinones, begin to dissociate at the very beginning of melanin hydration were indicated. As such, we suggest a modification to the common hydration-dependent conductivity mechanism and propose that the conductivity at low hydration is dominated by carboxylic acid protons, whereas higher hydration levels manifest semiquinone protons.
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Affiliation(s)
- Zakhar V. Bedran
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Institute Lane 9, 141701 Dolgoprudny, Russia; (Z.V.B.); (S.S.Z.); (P.A.A.); (I.O.T.); (B.P.G.)
| | - Sergey S. Zhukov
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Institute Lane 9, 141701 Dolgoprudny, Russia; (Z.V.B.); (S.S.Z.); (P.A.A.); (I.O.T.); (B.P.G.)
| | - Pavel A. Abramov
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Institute Lane 9, 141701 Dolgoprudny, Russia; (Z.V.B.); (S.S.Z.); (P.A.A.); (I.O.T.); (B.P.G.)
| | - Ilya O. Tyurenkov
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Institute Lane 9, 141701 Dolgoprudny, Russia; (Z.V.B.); (S.S.Z.); (P.A.A.); (I.O.T.); (B.P.G.)
| | - Boris P. Gorshunov
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Institute Lane 9, 141701 Dolgoprudny, Russia; (Z.V.B.); (S.S.Z.); (P.A.A.); (I.O.T.); (B.P.G.)
| | - A. Bernardus Mostert
- Department of Chemistry, Swansea University, Singleton Park, Swansea SA2 8PP, UK;
| | - Konstantin A. Motovilov
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Institute Lane 9, 141701 Dolgoprudny, Russia; (Z.V.B.); (S.S.Z.); (P.A.A.); (I.O.T.); (B.P.G.)
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Exploring the UVB-protective efficacy of melanin precursor extracted from marine imperfect fungus: Featuring characterization and application studies under in vitro conditions. Int Microbiol 2018; 21:59-71. [DOI: 10.1007/s10123-018-0005-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/20/2018] [Accepted: 04/06/2018] [Indexed: 01/30/2023]
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Mondal S, Thampi A, Puranik M. Kinetics of Melanin Polymerization during Enzymatic and Nonenzymatic Oxidation. J Phys Chem B 2018; 122:2047-2063. [PMID: 29364665 DOI: 10.1021/acs.jpcb.7b07941] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanin is an abundant biopigment in the animal kingdom, but its structure remains poorly understood. This is a substantial impediment to understanding the mechanistic origin of its observed functions. Proposed models of melanin structure include aggregates of both linear and macrocyclic units and noncovalently held monomers. Both models are broadly in agreement with current experimental data. To constrain the structural and kinetic models of melanin, experimental data of high resolution with chemical specificity accompanied by atomistic modeling are required. We have addressed this by obtaining electronic absorption, infrared, and ultraviolet resonance Raman (RR) spectra of melanin at several wavelengths of excitation that are sensitive to small changes in structure. From these experiments, we observed kinetics of the formation of different species en route to melanin polymerization. Exclusive chemical signatures of monomer 3,4-dihydroxyphenylalanine (dopa), intermediate dopachrome (DC), and early-time polymer are established through their vibrational bands at 1292, 1670, and 1616 cm-1 respectively. Direct evidence of reduced heterogeneity of melanin oligomers in tyrosinase-induced formation is provided from experimental measurements of vibrational bandwidths. Models made with density functional theory show that the linear homopolymeric structures of 5,6-dihydroxyindole can account for experimentally observed wavenumbers and broad bandwidth in Raman spectra of dopa-melanin. We capture resonance Raman (RR) signature of DC, the intermediate stabilized by the enzyme tyrosinase, for the first time in an enzyme-assisted melanization reaction using 488 nm excitation wavelength and propose that this wavelength can be used to probe reaction intermediates of melanin formation in solution.
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Affiliation(s)
- Sayan Mondal
- Indian Institute of Science Education and Research , Pune 411008, India
| | - Arya Thampi
- Indian Institute of Science Education and Research , Pune 411008, India
| | - Mrinalini Puranik
- Indian Institute of Science Education and Research , Pune 411008, India
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Perna G, Lasalvia M, Capozzi V. Vibrational spectroscopy of synthetic and natural eumelanin. POLYM INT 2016. [DOI: 10.1002/pi.5182] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Giuseppe Perna
- Dipartimento di Medicina Clinica e Sperimentale; Università degli studi di Foggia; via Napoli 20 71122 Foggia Italy
| | - Maria Lasalvia
- Dipartimento di Medicina Clinica e Sperimentale; Università degli studi di Foggia; via Napoli 20 71122 Foggia Italy
| | - Vito Capozzi
- Dipartimento di Medicina Clinica e Sperimentale; Università degli studi di Foggia; via Napoli 20 71122 Foggia Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Bari; Via Orabona 4 70126 Bari Italy
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De Marchi F, Cui D, Lipton-Duffin J, Santato C, MacLeod JM, Rosei F. Self-assembly of indole-2-carboxylic acid at graphite and gold surfaces. J Chem Phys 2015; 142:101923. [DOI: 10.1063/1.4908143] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Fabrizio De Marchi
- Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada
| | - Daling Cui
- Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada
| | - Josh Lipton-Duffin
- Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada
| | - Clara Santato
- Département de Génie physique, École Polytechnique de Montréal, C.P. 6079, Succ. Centre Ville, Montréal, Quebec H3C 3A7, Canada
| | - Jennifer M. MacLeod
- Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada
| | - Federico Rosei
- Centre Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2, Canada
- Center for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
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Huijser A, Rode MF, Corani A, Sobolewski AL, Sundström V. Photophysics of indole-2-carboxylic acid in an aqueous environment studied by fluorescence spectroscopy in combination with ab initio calculations. Phys Chem Chem Phys 2012; 14:2078-86. [DOI: 10.1039/c2cp22958g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Huijser A, Pezzella A, Sundström V. Functionality of epidermal melanin pigments: current knowledge on UV-dissipative mechanisms and research perspectives. Phys Chem Chem Phys 2011; 13:9119-27. [DOI: 10.1039/c1cp20131j] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gamble AB, Keller PA. Synthesis of reaction-ready 6,6′-biindole and 6,6′-biisatin via palladium(ii)-catalysed intramolecular C–H functionalisation. Chem Commun (Camb) 2010; 46:4076-8. [DOI: 10.1039/c002098b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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d'Ischia M, Napolitano A, Pezzella A, Meredith P, Sarna T. Chemische und strukturelle Vielfalt der Eumelanine - ein kaum erforschtes optoelektronisches Biopolymer. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200803786] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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d'Ischia M, Napolitano A, Pezzella A, Meredith P, Sarna T. Chemical and structural diversity in eumelanins: unexplored bio-optoelectronic materials. Angew Chem Int Ed Engl 2009; 48:3914-21. [PMID: 19294706 PMCID: PMC2799031 DOI: 10.1002/anie.200803786] [Citation(s) in RCA: 373] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Eumelanins, the characteristic black, insoluble, and heterogeneous biopolymers of human skin, hair, and eyes, have intrigued and challenged generations of chemists, physicists, and biologists because of their unique structural and optoelectronic properties. Recently, the methods of organic chemistry have been combined with advanced spectroscopic and imaging techniques, theoretical calculations, and methods of condensed-matter physics to gradually force these materials to reveal their secrets. Herein we review the latest advances in the field with a view to showing how the emerging knowledge is not only helping to explain eumelanin functionality, but may also be translated into effective strategies for exploiting their properties to create a new class of biologically inspired high-tech materials.
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Affiliation(s)
- Marco d'Ischia
- Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126, Naples, Italy.
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Duong HA, Chua S, Huleatt PB, Chai CLL. Synthesis of Biindolyls via Palladium-Catalyzed Reactions. J Org Chem 2008; 73:9177-80. [DOI: 10.1021/jo801846b] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hung A. Duong
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1 Pesek Rd, Jurong Island, Singapore 627833
| | - Sheena Chua
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1 Pesek Rd, Jurong Island, Singapore 627833
| | - Paul B. Huleatt
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1 Pesek Rd, Jurong Island, Singapore 627833
| | - Christina L. L. Chai
- Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1 Pesek Rd, Jurong Island, Singapore 627833
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Simon JD, Hong L, Peles DN. Insights into melanosomes and melanin from some interesting spatial and temporal properties. J Phys Chem B 2008; 112:13201-17. [PMID: 18817437 DOI: 10.1021/jp804248h] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanosomes are organelles found in a wide variety of tissues throughout the animal kingdom and exhibit a range of different shapes: spheres of up to approximately 1 mum diameters and ellipsoids with lengths of up to approximately 2 mum and varying aspect ratios. The functions of melanosomes include photoprotection, mitigation of the effects of reactive oxygen species, and metal chelation. The melanosome contains a variety of biological molecules, e.g., proteins and lipids, but the dominant constituent is the pigment melanin, and the functions ascribed to melanosomes are uniquely enabled by the chemical properties of the melanins they contain. In the past decade, there has been significant progress in understanding melanins and their impact on human health. While the molecular details of melanin production and how the pigment is organized within the melanosome determine its properties and biological functions, the physical and chemical properties of the surface of the melanosome are central to their range of ascribed functions. Surprisingly, few studies designed to probe this biological surface have been reported. In this article, we discuss recent work using surface-sensitive analytic, spectroscopic, and imaging techniques to examine the structural and chemical properties of many types of natural pigments: sepia melanin granules, human and bovine ocular melanosomes, human hair melanosomes, and neuromelanin. N 2 adsorption/desorption measurements and atomic force microscopy provide novel insights into surface morphology. The chemical properties of the melanins present on the surface are revealed by X-ray photoelectron spectroscopy and photoemission electron microscopy. These technologies are also applied to elucidate changes in surface properties that occur with aging. Specifically, studies of the surface properties of human retinal pigment epithelium melanosomes as a function of age are stimulating the development of models for their age-dependent behaviors. The article concludes with a brief discussion of important unanswered research questions in this field.
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Affiliation(s)
- John D Simon
- Department of Chemistry, Duke UNiversity, Durham, NC, USA
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