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Rybicka-Jasińska K, Derr JB, Vullev VI. What defines biomimetic and bioinspired science and engineering? PURE APPL CHEM 2021. [DOI: 10.1515/pac-2021-0323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Abstract
Biomimicry, biomimesis and bioinspiration define distinctly different approaches for deepening the understanding of how living systems work and employing this knowledge to meet pressing demands in engineering. Biomimicry involves shear imitation of biological structures that most often do not reproduce the functionality that they have while in the living organisms. Biomimesis aims at reproduction of biological structure-function relationships and advances our knowledge of how different components of complex living systems work. Bioinspiration employs this knowledge in abiotic manners that are optimal for targeted applications. This article introduces and reviews these concepts in a global historic perspective. Representative examples from charge-transfer science and solar-energy engineering illustrate the evolution from biomimetic to bioinspired approaches and show their importance. Bioinspired molecular electrets, aiming at exploration of dipole effects on charge transfer, demonstrate the pintail impacts of biological inspiration that reach beyond its high utilitarian values. The abiotic character of bioinspiration opens doors for the emergence of unprecedented properties and phenomena, beyond what nature can offer.
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Affiliation(s)
| | - James B. Derr
- Department of Biochemistry , University of California , Riverside , CA , 92521 , USA
| | - Valentine I. Vullev
- Department of Biochemistry , University of California , Riverside , CA , 92521 , USA
- Department of Bioengineering , University of California , Riverside , CA , 92521 , USA
- Department of Chemistry , University of California , Riverside , CA , 92521 , USA
- Materials Science and Engineering Program , University of California , Riverside , CA , 92521 , USA
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Role of intramolecular hydrogen bonds in promoting electron flow through amino acid and oligopeptide conjugates. Proc Natl Acad Sci U S A 2021; 118:2026462118. [PMID: 33707214 DOI: 10.1073/pnas.2026462118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Elucidating the factors that control charge transfer rates in relatively flexible conjugates is of importance for understanding energy flows in biology as well as assisting the design and construction of electronic devices. Here, we report ultrafast electron transfer (ET) and hole transfer (HT) between a corrole (Cor) donor linked to a perylene-diimide (PDI) acceptor by a tetrameric alanine (Ala)4 Selective photoexcitation of the donor and acceptor triggers subpicosecond and picosecond ET and HT. Replacement of the (Ala)4 linker with either a single alanine or phenylalanine does not substantially affect the ET and HT kinetics. We infer that electronic coupling in these reactions is not mediated by tetrapeptide backbone nor by direct donor-acceptor interactions. Employing a combination of NMR, circular dichroism, and computational studies, we show that intramolecular hydrogen bonding brings the donor and the acceptor into proximity in a "scorpion-shaped" molecular architecture, thereby accounting for the unusually high ET and HT rates. Photoinduced charge transfer relies on a (Cor)NH…O=C-NH…O=C(PDI) electronic-coupling pathway involving two pivotal hydrogen bonds and a central amide group as a mediator. Our work provides guidelines for construction of effective donor-acceptor assemblies linked by long flexible bridges as well as insights into structural motifs for mediating ET and HT in proteins.
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Derr JB, Rybicka-Jasińska K, Espinoza EM, Morales M, Billones MK, Clark JA, Vullev VI. On the Search of a Silver Bullet for the Preparation of Bioinspired Molecular Electrets with Propensity to Transfer Holes at High Potentials. Biomolecules 2021; 11:429. [PMID: 33804209 PMCID: PMC8001849 DOI: 10.3390/biom11030429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/01/2021] [Accepted: 03/07/2021] [Indexed: 01/24/2023] Open
Abstract
Biological structure-function relationships offer incomparable paradigms for charge-transfer (CT) science and its implementation in solar-energy engineering, organic electronics, and photonics. Electrets are systems with co-directionally oriented electric dopes with immense importance for CT science, and bioinspired molecular electrets are polyamides of anthranilic-acid derivatives with designs originating from natural biomolecular motifs. This publication focuses on the synthesis of molecular electrets with ether substituents. As important as ether electret residues are for transferring holes under relatively high potentials, the synthesis of their precursors presents formidable challenges. Each residue in the molecular electrets is introduced as its 2-nitrobenzoic acid (NBA) derivative. Hence, robust and scalable synthesis of ether derivatives of NBA is essential for making such hole-transfer molecular electrets. Purdie-Irvine alkylation, using silver oxide, produces with 90% yield the esters of the NBA building block for iso-butyl ether electrets. It warrants additional ester hydrolysis for obtaining the desired NBA precursor. Conversely, Williamson etherification selectively produces the same free-acid ether derivative in one-pot reaction, but a 40% yield. The high yields of Purdie-Irvine alkylation and the selectivity of the Williamson etherification provide important guidelines for synthesizing building blocks for bioinspired molecular electrets and a wide range of other complex ether conjugates.
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Affiliation(s)
- James Bennett Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA;
| | | | - Eli Misael Espinoza
- Department of Chemistry, University of California, Riverside, CA 92521, USA; (E.M.E.); (M.M.)
| | - Maryann Morales
- Department of Chemistry, University of California, Riverside, CA 92521, USA; (E.M.E.); (M.M.)
| | | | - John Anthony Clark
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; (K.R.-J.); (J.A.C.)
| | - Valentine Ivanov Vullev
- Department of Biochemistry, University of California, Riverside, CA 92521, USA;
- Department of Bioengineering, University of California, Riverside, CA 92521, USA; (K.R.-J.); (J.A.C.)
- Department of Chemistry, University of California, Riverside, CA 92521, USA; (E.M.E.); (M.M.)
- Department of Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA
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Derr JB, Tamayo J, Clark JA, Morales M, Mayther MF, Espinoza EM, Rybicka-Jasińska K, Vullev VI. Multifaceted aspects of charge transfer. Phys Chem Chem Phys 2020; 22:21583-21629. [PMID: 32785306 PMCID: PMC7544685 DOI: 10.1039/d0cp01556c] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Charge transfer and charge transport are by far among the most important processes for sustaining life on Earth and for making our modern ways of living possible. Involving multiple electron-transfer steps, photosynthesis and cellular respiration have been principally responsible for managing the energy flow in the biosphere of our planet since the Great Oxygen Event. It is impossible to imagine living organisms without charge transport mediated by ion channels, or electron and proton transfer mediated by redox enzymes. Concurrently, transfer and transport of electrons and holes drive the functionalities of electronic and photonic devices that are intricate for our lives. While fueling advances in engineering, charge-transfer science has established itself as an important independent field, originating from physical chemistry and chemical physics, focusing on paradigms from biology, and gaining momentum from solar-energy research. Here, we review the fundamental concepts of charge transfer, and outline its core role in a broad range of unrelated fields, such as medicine, environmental science, catalysis, electronics and photonics. The ubiquitous nature of dipoles, for example, sets demands on deepening the understanding of how localized electric fields affect charge transfer. Charge-transfer electrets, thus, prove important for advancing the field and for interfacing fundamental science with engineering. Synergy between the vastly different aspects of charge-transfer science sets the stage for the broad global impacts that the advances in this field have.
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Affiliation(s)
- James B Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA.
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Molecular electrets – Why do dipoles matter for charge transfer and excited-state dynamics? J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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6
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Skonieczny K, Espinoza EM, Derr JB, Morales M, Clinton JM, Xia B, Vullev VI. Biomimetic and bioinspired molecular electrets. How to make them and why does the established peptide chemistry not always work? PURE APPL CHEM 2020. [DOI: 10.1515/pac-2019-0111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract“Biomimetic” and “bioinspired” define different aspects of the impacts that biology exerts on science and engineering. Biomimicking improves the understanding of how living systems work, and builds tools for bioinspired endeavors. Biological inspiration takes ideas from biology and implements them in unorthodox manners, exceeding what nature offers. Molecular electrets, i.e. systems with ordered electric dipoles, are key for advancing charge-transfer (CT) science and engineering. Protein helices and their biomimetic analogues, based on synthetic polypeptides, are the best-known molecular electrets. The inability of native polypeptide backbones to efficiently mediate long-range CT, however, limits their utility. Bioinspired molecular electrets based on anthranilamides can overcome the limitations of their biological and biomimetic counterparts. Polypeptide helices are easy to synthesize using established automated protocols. These protocols, however, fail to produce even short anthranilamide oligomers. For making anthranilamides, the residues are introduced as their nitrobenzoic-acid derivatives, and the oligomers are built from their C- to their N-termini via amide-coupling and nitro-reduction steps. The stringent requirements for these reduction and coupling steps pose non-trivial challenges, such as high selectivity, quantitative yields, and fast completion under mild conditions. Addressing these challenges will provide access to bioinspired molecular electrets essential for organic electronics and energy conversion.
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Affiliation(s)
- Kamil Skonieczny
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44-52, 01-224 Warsaw, Poland
| | - Eli M. Espinoza
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - James B. Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
| | - Maryann Morales
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Jillian M. Clinton
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Bing Xia
- GlaxoSmithKline, 200 Cambridgepark Dr., Cambridge, MA 02140, USA
| | - Valentine I. Vullev
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
- Department of Chemistry, University of California, Riverside, CA 92521, USA
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
- Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA
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Derr JB, Tamayo J, Espinoza EM, Clark JA, Vullev VI. Dipole-induced effects on charge transfer and charge transport. Why do molecular electrets matter? CAN J CHEM 2018. [DOI: 10.1139/cjc-2017-0389] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Charge transfer (CT) and charge transport (CTr) are at the core of life-sustaining biological processes and of processes that govern the performance of electronic and energy-conversion devices. Electric fields are invaluable for guiding charge movement. Therefore, as electrostatic analogues of magnets, electrets have unexplored potential for generating local electric fields for accelerating desired CT processes and suppressing undesired ones. The notion about dipole-generated local fields affecting CT has evolved since the middle of the 20th century. In the 1990s, the first reports demonstrating the dipole effects on the kinetics of long-range electron transfer appeared. Concurrently, the development of molecular-level designs of electric junctions has led the exploration of dipole effects on CTr. Biomimetic molecular electrets such as polypeptide helices are often the dipole sources in CT systems. Conversely, surface-charge electrets and self-assembled monolayers of small polar conjugates are the preferred sources for modifying interfacial electric fields for controlling CTr. The multifaceted complexity of such effects on CT and CTr testifies for the challenges and the wealth of this field that still remains largely unexplored. This review outlines the basic concepts about dipole effects on CT and CTr, discusses their evolution, and provides accounts for their future developments and impacts.
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Affiliation(s)
- James B. Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
| | - Jesse Tamayo
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - Eli M. Espinoza
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | - John A. Clark
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Valentine I. Vullev
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
- Department of Chemistry, University of California, Riverside, CA 92521, USA
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
- Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA
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Espinoza EM, Larsen-Clinton JM, Krzeszewski M, Darabedian N, Gryko DT, Vullev VI. Bioinspired approach toward molecular electrets: synthetic proteome for materials. PURE APPL CHEM 2017. [DOI: 10.1515/pac-2017-0309] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AbstractMolecular-level control of charge transfer (CT) is essential for both, organic electronics and solar-energy conversion, as well as for a wide range of biological processes. This article provides an overview of the utility of local electric fields originating from molecular dipoles for directing CT processes. Systems with ordered dipoles, i.e. molecular electrets, are the centerpiece of the discussion. The conceptual evolution from biomimicry to biomimesis, and then to biological inspiration, paves the roads leading from testing the understanding of how natural living systems function to implementing these lessons into optimal paradigms for specific applications. This progression of the evolving structure-function relationships allows for the development of bioinspired electrets composed of non-native aromatic amino acids. A set of such non-native residues that are electron-rich can be viewed as a synthetic proteome for hole-transfer electrets. Detailed considerations of the electronic structure of an individual residue prove of key importance for designating the points for optimal injection of holes (i.e. extraction of electrons) in electret oligomers. This multifaceted bioinspired approach for the design of CT molecular systems provides unexplored paradigms for electronic and energy science and engineering.
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Affiliation(s)
- Eli M. Espinoza
- Department of Chemistry, University of California, Riverside, CA 92521, USA
| | | | - Maciej Krzeszewski
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44-52, 01-224 Warsaw, Poland
| | - Narek Darabedian
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Daniel T. Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44-52, 01-224 Warsaw, Poland
| | - Valentine I. Vullev
- Department of Chemistry, University of California, Riverside, CA 92521, USA
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
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Li X, Markandeya N, Jonusauskas G, McClenaghan ND, Maurizot V, Denisov SA, Huc I. Photoinduced Electron Transfer and Hole Migration in Nanosized Helical Aromatic Oligoamide Foldamers. J Am Chem Soc 2016; 138:13568-13578. [DOI: 10.1021/jacs.6b05668] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Xuesong Li
- Univ. de Bordeaux, CBMN (UMR 5248), Institut Européen
de Chimie et Biologie, 2 rue Robert Escarpit, 33600 Pessac, France
- CNRS, CBMN (UMR 5248), Institut Européen
de Chimie et Biologie, 2 rue Robert Escarpit, 33600 Pessac, France
| | - Nagula Markandeya
- Univ. de Bordeaux, CBMN (UMR 5248), Institut Européen
de Chimie et Biologie, 2 rue Robert Escarpit, 33600 Pessac, France
- CNRS, CBMN (UMR 5248), Institut Européen
de Chimie et Biologie, 2 rue Robert Escarpit, 33600 Pessac, France
| | - Gediminas Jonusauskas
- Univ. de Bordeaux, Laboratoire Ondes et Matières
d’Aquitaine (UMR5798), 351 cours de la Libération, 33405 Talence cedex, France
| | - Nathan D. McClenaghan
- Univ. de Bordeaux, Institut des Sciences Moléculaires
(UMR5255), 351 cours de
la Libération, 33405 Talence cedex, France
| | - Victor Maurizot
- CNRS, CBMN (UMR 5248), Institut Européen
de Chimie et Biologie, 2 rue Robert Escarpit, 33600 Pessac, France
| | - Sergey A. Denisov
- Univ. de Bordeaux, Institut des Sciences Moléculaires
(UMR5255), 351 cours de
la Libération, 33405 Talence cedex, France
| | - Ivan Huc
- CNRS, CBMN (UMR 5248), Institut Européen
de Chimie et Biologie, 2 rue Robert Escarpit, 33600 Pessac, France
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Espinoza EM, Xia B, Darabedian N, Larsen JM, Nuñez V, Bao D, Mac JT, Botero F, Wurch M, Zhou F, Vullev VI. Nitropyrene Photoprobes: Making Them, and What Are They Good for? European J Org Chem 2015. [DOI: 10.1002/ejoc.201501339] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Larsen JM, Espinoza EM, Hartman JD, Lin CK, Wurch M, Maheshwari P, Kaushal RK, Marsella MJ, Beran GJO, Vullev VI. Building blocks for bioinspired electrets: molecular-level approach to materials for energy and electronics. PURE APPL CHEM 2015. [DOI: 10.1515/pac-2015-0109] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AbstractIn biology, an immense diversity of protein structural and functional motifs originates from only 20 common proteinogenic native amino acids arranged in various sequences. Is it possible to attain the same diversity in electronic materials based on organic macromolecules composed of non-native residues with different characteristics? This publication describes the design, preparation and characterization of non-native aromatic β-amino acid residues, i.e. derivatives of anthranilic acid, for polyamides that can efficiently mediate hole transfer. Chemical derivatization with three types of substituents at two positions of the aromatic ring allows for adjusting the energy levels of the frontier orbitals of the anthranilamide residues over a range of about one electronvolt. Most importantly, the anthranilamide residues possess permanent electric dipoles, adding to the electronic properties of the bioinspired conjugates they compose, making them molecular electrets.
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Affiliation(s)
- Jillian M. Larsen
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Eli M. Espinoza
- 2Department of Chemistry, University of California, Riverside, CA, 92507, USA
| | - Joshua D. Hartman
- 2Department of Chemistry, University of California, Riverside, CA, 92507, USA
| | - Chung-Kuang Lin
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Michelle Wurch
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Payal Maheshwari
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Raman K. Kaushal
- 1Department of Bioengineering, University of California, Riverside, CA, 92507, USA
| | - Michael J. Marsella
- 2Department of Chemistry, University of California, Riverside, CA, 92507, USA
| | - Gregory J. O. Beran
- 2Department of Chemistry, University of California, Riverside, CA, 92507, USA
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Amdursky N. Electron Transfer across Helical Peptides. Chempluschem 2015; 80:1075-1095. [DOI: 10.1002/cplu.201500121] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/06/2015] [Indexed: 02/05/2023]
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Holbrook RJ, Weinberg DJ, Peterson MD, Weiss EA, Meade TJ. Light-activated protein inhibition through photoinduced electron transfer of a ruthenium(II)-cobalt(III) bimetallic complex. J Am Chem Soc 2015; 137:3379-85. [PMID: 25671465 DOI: 10.1021/jacs.5b00342] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We describe a mechanism of light activation that initiates protein inhibitory action of a biologically inert Co(III) Schiff base (Co(III)-sb) complex. Photoinduced electron transfer (PET) occurs from a Ru(II) bipyridal complex to a covalently attached Co(III) complex and is gated by conformational changes that occur in tens of nanoseconds. Reduction of the Co(III)-sb by PET initiates displacement of the inert axial imidazole ligands, promoting coordination to active site histidines of α-thrombin. Upon exposure to 455 nm light, the rate of ligand exchange with 4-methylimidazole, a histidine mimic, increases by approximately 5-fold, as observed by NMR spectroscopy. Similarly, the rate of α-thrombin inhibition increases over 5-fold upon irradiation. These results convey a strategy for light activation of inorganic therapeutic agents through PET utilizing redox-active metal centers.
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Affiliation(s)
- Robert J Holbrook
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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14
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Juhaniewicz J, Pawlowski J, Sek S. Electron Transport Mediated by Peptides Immobilized on Surfaces. Isr J Chem 2015. [DOI: 10.1002/ijch.201400165] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Tarakeshwar P, Palma JL, Holland GP, Fromme P, Yarger JL, Mujica V. Probing the Nature of Charge Transfer at Nano-Bio Interfaces: Peptides on Metal Oxide Nanoparticles. J Phys Chem Lett 2014; 5:3555-3559. [PMID: 26278609 DOI: 10.1021/jz501854x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Characterizing the nano-bio interface has been a long-standing endeavor in the quest for novel biosensors, biophotovoltaics, and biocompatible electronic devices. In this context, the present computational work on the interaction of two peptides, A6K (Ac-AAAAAAK-NH2) and A7 (Ac-AAAAAAA-NH2) with semiconducting TiO2 nanoparticles is an effort to understand the peptide-metal oxide nanointerface. These investigations were spurred by recent experimental observations that nanostructured semiconducting metal oxides templated with A6K peptides not only stabilize large proteins like photosystem-I (PS-I) but also exhibit enhanced charge-transfer characteristics. Our results indicate that α-helical structures of A6K are not only energetically more stabilized on TiO2 nanoparticles, but the resulting hybrids also exhibit enhanced electron transfer characteristics. This enhancement can be attributed to substantial changes in the electronic characteristics at the peptide-TiO2 interface. Apart from understanding the mechanism of electron transfer (ET) in peptide-stabilized PS-I on metal oxide nanoparticles, the current work also has implications in the development of novel solar cells and photocatalysts.
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Affiliation(s)
- Pilarisetty Tarakeshwar
- †Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Julio L Palma
- ‡Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-5001, United States
| | - Gregory P Holland
- §Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, United States
| | - Petra Fromme
- †Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Jeffery L Yarger
- †Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Vladimiro Mujica
- †Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
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Bao D, Upadhyayula S, Larsen JM, Xia B, Georgieva B, Nuñez V, Espinoza EM, Hartman JD, Wurch M, Chang A, Lin CK, Larkin J, Vasquez K, Beran GJO, Vullev VI. Dipole-mediated rectification of intramolecular photoinduced charge separation and charge recombination. J Am Chem Soc 2014; 136:12966-73. [PMID: 25162490 DOI: 10.1021/ja505618n] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Controlling charge transfer at a molecular scale is critical for efficient light harvesting, energy conversion, and nanoelectronics. Dipole-polarization electrets, the electrostatic analogue of magnets, provide a means for "steering" electron transduction via the local electric fields generated by their permanent electric dipoles. Here, we describe the first demonstration of the utility of anthranilamides, moieties with ordered dipoles, for controlling intramolecular charge transfer. Donor-acceptor dyads, each containing a single anthranilamide moiety, distinctly rectify both the forward photoinduced electron transfer and the subsequent charge recombination. Changes in the observed charge-transfer kinetics as a function of media polarity were consistent with the anticipated effects of the anthranilamide molecular dipoles on the rectification. The regioselectivity of electron transfer and the molecular dynamics of the dyads further modulated the observed kinetics, particularly for charge recombination. These findings reveal the underlying complexity of dipole-induced effects on electron transfer and demonstrate unexplored paradigms for molecular rectifiers.
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Affiliation(s)
- Duoduo Bao
- Department of Bioengineering, ‡Department of Biochemistry, §Department of Chemistry, and ∥Materials Science and Engineering Program, University of California , Riverside, California 92521, United States
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17
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Nuñez V, Upadhyayula S, Millare B, Larsen JM, Hadian A, Shin S, Vandrangi P, Gupta S, Xu H, Lin AP, Georgiev GY, Vullev VI. Microfluidic Space-Domain Time-Resolved Emission Spectroscopy of Terbium(III) and Europium(III) Chelates with Pyridine-2,6-Dicarboxylate. Anal Chem 2013; 85:4567-77. [DOI: 10.1021/ac400200x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Vicente Nuñez
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Srigokul Upadhyayula
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521,
United States
| | - Brent Millare
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Jillian M. Larsen
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Ali Hadian
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Sanghoon Shin
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Prashanthi Vandrangi
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Sharad Gupta
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Hong Xu
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Adam P. Lin
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Georgi Y. Georgiev
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
| | - Valentine I. Vullev
- Department of Bioengineering
and Center for Bioengineering Research, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521,
United States
- Department
of Chemistry, University of California,
Riverside, California 92521,
United States
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18
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Xia B, Bao D, Upadhyayula S, Jones G, Vullev VI. Anthranilamides as bioinspired molecular electrets: experimental evidence for a permanent ground-state electric dipole moment. J Org Chem 2013; 78:1994-2004. [PMID: 23270467 DOI: 10.1021/jo301942g] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
As electrostatic equivalents of magnets, organic electrets offer unparalleled properties for impacting energy conversion and electronic applications. While biological systems have evolved to efficiently utilize protein α-helices as molecular electrets, the synthetic counterparts of these conjugates still remain largely unexplored. This paper describes a study of the electronic properties of anthranilamide oligomers, which proved to be electrets based on their intrinsic dipole moments as evident from their spectral and dielectric properties. NMR studies provided the means for estimating the direction of the intrinsic electric dipoles of these conjugates. This study sets the foundation for the development of a class of organic materials that are de novo designed from biomolecular motifs and possess unexplored electronic properties.
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Affiliation(s)
- Bing Xia
- Department of Bioengineering, University of California, Riverside, California 92521, United States
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19
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Jeong HS, Choi SM, Kim HW, Park JW, Park HN, Park SM, Jang SK, Rhee YM, Kim BH. Fluorescent peptide indicator displacement assay for monitoring interactions between RNA and RNA binding proteins. ACTA ACUST UNITED AC 2013; 9:948-51. [DOI: 10.1039/c2mb25470k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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20
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Abstract
Electrochemical studies of a set of ferrocene-labeled helical peptides of increasing length were carried out by forming self-assembled monolayers (SAMs) on gold electrodes. Electron transfer (ET) rates showed a very weakly distance dependent nature that has been interpreted as a result of a dynamically controlled tunneling mechanism. Specifically, the slow equilibrium between the α- and the 310 helical conformers in a SAM has been invoked, and the rate of formation of the more conductive 310 conformer has been proposed to be related to the ET rates observed.
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Affiliation(s)
- Himadri Shekhar Mandal
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
| | - Heinz-Bernhard Kraatz
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
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21
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Upadhyayula S, Bao D, Millare B, Sylvia SS, Habib KMM, Ashraf K, Ferreira A, Bishop S, Bonderer R, Baqai S, Jing X, Penchev M, Ozkan M, Ozkan CS, Lake RK, Vullev VI. Permanent electric dipole moments of carboxyamides in condensed media: what are the limitations of theory and experiment? J Phys Chem B 2011; 115:9473-90. [PMID: 21682315 DOI: 10.1021/jp2045383] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Electrostatic properties of proteins are crucial for their functionality. Carboxyamides are small polar groups that, as peptide bonds, are principal structural components of proteins that govern their electrostatic properties. We investigated the medium dependence of the molar polarization and of the permanent dipole moments of amides with different state of alkylation. The experimentally measured and theoretically calculated dipole moments manifested a solvent dependence that increased with the increase in the media polarity. We ascribed the observed enhancement of the amide polarization to the reaction fields in the solvated cavities. Chloroform, for example, caused about a 25% increase in the amide dipole moments determined for vacuum, as the experimental and theoretical results demonstrated. Another chlorinated solvent, 1,1,2,2-tetrachloroethane, however, caused an "abnormal" increase in the experimentally measured amide dipoles, which the theoretical approaches we used could not readily quantify. We showed and discussed alternatives for addressing such discrepancies between theory and experiment.
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Affiliation(s)
- Srigokul Upadhyayula
- Department of Bioengineering, University of California, Riverside, California 92521, United States
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22
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Abstract
Bacterial endospores are some of the most resilient forms of life known to us, with their persistent survival capability resulting from a complex and effective structural organization. The outer membrane of endospores is surrounded by the densely packed endospore coat and exosporium, containing amyloid or amyloid-like proteins. In fact, it is the impenetrable composition of the endospore coat and the exosporium that makes staining methodologies for endospore detection complex and challenging. Therefore, a plausible strategy for facile and expedient staining would be to target components of the protective surface layers of the endospores. Instead of targeting endogenous markers encapsulated in the spores, here we demonstrated staining of these dormant life entities that targets the amyloid domains, i.e., the very surface components that make the coats of these species impenetrable. Using an amyloid staining dye, thioflavin T (ThT), we examined this strategy. A short incubation of bacillus endospore suspensions with ThT, under ambient conditions, resulted in (i) an enhancement of the fluorescence of ThT and (ii) the accumulation of ThT in the endospores, affording fluorescence images with excellent contrast ratios. Fluorescence images revealed that ThT tends to accumulate in the surface regions of the endospores. The observed fluorescence enhancement and dye accumulation, coupled with the sensitivity of emission techniques, provide an effective and rapid means of staining endospores without the inconvenience of pre- or posttreatment of samples.
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23
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Kumar RJ, MacDonald JM, Singh TB, Waddington LJ, Holmes AB. Hierarchical Self-Assembly of Semiconductor Functionalized Peptide α-Helices and Optoelectronic Properties. J Am Chem Soc 2011; 133:8564-73. [DOI: 10.1021/ja110858k] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rohan J. Kumar
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South, Victoria 3169, Australia
| | - James M. MacDonald
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South, Victoria 3169, Australia
| | - Th. Birendra Singh
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South, Victoria 3169, Australia
| | - Lynne J. Waddington
- CSIRO Materials Science and Engineering, 343 Royal Parade, Parkville, VIC 3052, Australia
| | - Andrew B. Holmes
- CSIRO Materials Science and Engineering, Private Bag 10, Clayton South, Victoria 3169, Australia
- School of Chemistry, Bio21 Institute, University of Melbourne, VIC 3010, Australia
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24
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Thomas MS, Nuñez V, Upadhyayula S, Zielins ER, Bao D, Vasquez JM, Bahmani B, Vullev VI. Kinetics of bacterial fluorescence staining with 3,3'-diethylthiacyanine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:9756-9765. [PMID: 20481488 DOI: 10.1021/la1013279] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
For more than a century, colorimetric and fluorescence staining have been the foundation of a broad range of key bioanalytical techniques. The dynamics of such staining processes, however, still remains largely unexplored. We investigated the kinetics of fluorescence staining of two gram-negative and two gram-positive species with 3,3'-diethylthiacyanine (THIA) iodide. An increase in the THIA fluorescence quantum yield, induced by the bacterial dye uptake, was the principal reason for the observed emission enhancement. The fluorescence quantum yield of THIA depended on the media viscosity and not on the media polarity, which suggested that the microenvironment of the dye molecules taken up by the cells was restrictive. The kinetics of fluorescence staining did not manifest a statistically significant dependence neither on the dye concentration, nor on the cell count. In the presence of surfactant additives, however, the fluorescence-enhancement kinetic patterns manifested species specificity with statistically significant discernibility.
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Affiliation(s)
- Marlon S Thomas
- Department of Bioengineering, University of California, Riverside, California 92521, USA
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25
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Bao D, Ramu S, Contreras A, Upadhyayula S, Vasquez JM, Beran G, Vullev VI. Electrochemical Reduction of Quinones: Interfacing Experiment and Theory for Defining Effective Radii of Redox Moieties. J Phys Chem B 2010; 114:14467-79. [DOI: 10.1021/jp101730e] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Duoduo Bao
- Department of Bioengineering, University of California, Riverside, California 92521, Center for Bioengineering Research, University of California, Riverside, California 92521, and Department of Chemistry, University of California, Riverside, California 92521
| | - Sangeetha Ramu
- Department of Bioengineering, University of California, Riverside, California 92521, Center for Bioengineering Research, University of California, Riverside, California 92521, and Department of Chemistry, University of California, Riverside, California 92521
| | - Antonio Contreras
- Department of Bioengineering, University of California, Riverside, California 92521, Center for Bioengineering Research, University of California, Riverside, California 92521, and Department of Chemistry, University of California, Riverside, California 92521
| | - Srigokul Upadhyayula
- Department of Bioengineering, University of California, Riverside, California 92521, Center for Bioengineering Research, University of California, Riverside, California 92521, and Department of Chemistry, University of California, Riverside, California 92521
| | - Jacob M. Vasquez
- Department of Bioengineering, University of California, Riverside, California 92521, Center for Bioengineering Research, University of California, Riverside, California 92521, and Department of Chemistry, University of California, Riverside, California 92521
| | - Gregory Beran
- Department of Bioengineering, University of California, Riverside, California 92521, Center for Bioengineering Research, University of California, Riverside, California 92521, and Department of Chemistry, University of California, Riverside, California 92521
| | - Valentine I. Vullev
- Department of Bioengineering, University of California, Riverside, California 92521, Center for Bioengineering Research, University of California, Riverside, California 92521, and Department of Chemistry, University of California, Riverside, California 92521
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26
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Williams RM. Distance and orientation dependence of photoinduced electron transfer through twisted, bent and helical bridges: a Karplus relation for charge transfer interaction. Photochem Photobiol Sci 2010; 9:1018-26. [DOI: 10.1039/c0pp00050g] [Citation(s) in RCA: 23] [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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27
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Ashraf MK, Millare B, Gerasimenko AA, Bao D, Pandey RR, Lake RK, Vullev VI. Theoretical design of bioinspired macromolecular electrets based on anthranilamide derivatives. Biotechnol Prog 2009; 25:915-22. [PMID: 19452534 DOI: 10.1002/btpr.189] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Polypeptide helices possess considerable intrinsic dipole moments oriented along their axes. While for proline helices the dipoles originate solely from the ordered orientation of the amide bonds, for 3(10-) and alpha-helices the polarization resultant from the formation of hydrogen-bond network further increases the magnitude of the macromolecular dipoles. The enormous electric-field gradients, generated by the dipoles of alpha-helices (which amount to about 5 D per residue with 0.15 nm residue increments along the helix), play a crucial role in the selectivity and the transport properties of ion channels. The demonstration of dipole-induced rectification of vectorial charge transfer mediated by alpha-helices has opened a range of possibilities for applications of these macromolecules in molecular and biomolecular electronics. These biopolymers, however, possess relatively large bandgaps. As an alternative, we examined a series of synthetic macromolecules, aromatic oligo-ortho-amides, which form extended structures with amide bonds in ordered orientation, supported by a hydrogen-bond network. Unlike their biomolecular counterparts, the extended pi-conjugation of these macromolecules will produce bandgaps significantly smaller than the polypeptide bandgaps. Using ab initio density functional theory calculations, we modeled anthranilamide derivatives that are representative oligo-ortho-amide conjugates. Our calculations, indeed, showed intrinsic dipole moments oriented along the polymer axes and increasing with the increase in the length of the oligomers. Each anthranilamide residue contributed about 3 D to the vectorial macromolecular dipole. When we added electron donating (diethylamine) and electron withdrawing (nitro and trifluoromethyl) groups for n- and p-doping, respectively, we observed that: (1) proper positioning of the electron donating and withdrawing groups further polarized the aromatic residues, increasing the intrinsic dipole to about 4.5 D per residue; and (2) extension of the pi-conjugation over some of the doping groups narrowed the band gaps with as much as 1 eV. The investigated bioinspired systems offer alternatives for the development of broad range of organic electronic materials with nonlinear properties.
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Affiliation(s)
- M K Ashraf
- Department of Electrical Engineering, University of California, Riverside, CA 92521, USA.
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28
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Wolffs M, Delsuc N, Veldman D, Anh NV, Williams RM, Meskers SCJ, Janssen RAJ, Huc I, Schenning APHJ. Helical Aromatic Oligoamide Foldamers as Organizational Scaffolds for Photoinduced Charge Transfer. J Am Chem Soc 2009; 131:4819-29. [DOI: 10.1021/ja809367u] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Martin Wolffs
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Nicolas Delsuc
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Dirk Veldman
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Nguyễn Vân Anh
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - René M. Williams
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Stefan C. J. Meskers
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - René A. J. Janssen
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Ivan Huc
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Albertus P. H. J. Schenning
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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29
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Shi X, Duft D, Parks JH. Fluorescence Quenching Induced by Conformational Fluctuations in Unsolvated Polypeptides. J Phys Chem B 2008; 112:12801-15. [DOI: 10.1021/jp8033598] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiangguo Shi
- The Rowland Institute at Harvard, 100 Edwin H. Land Boulevard, Cambridge, Massachusetts 02142
| | - Denis Duft
- The Rowland Institute at Harvard, 100 Edwin H. Land Boulevard, Cambridge, Massachusetts 02142
| | - Joel H Parks
- The Rowland Institute at Harvard, 100 Edwin H. Land Boulevard, Cambridge, Massachusetts 02142
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30
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Kas OY, Charati MB, Rothberg LJ, Galvin ME, Kiick KL. Regulation of electronic behavior via confinement of PPV-based oligomers on peptide scaffolds. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b800860d] [Citation(s) in RCA: 18] [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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31
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Paulo PMR, Costa SMB. Interactions in noncovalent PAMAM/TMPyP systems studied by fluorescence spectroscopy. J Phys Chem B 2007; 109:13928-40. [PMID: 16852748 DOI: 10.1021/jp050894f] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Steady-state absorption and emission spectroscopy and time-resolved fluorescence measurements were employed in the study of meso-tetrakis(4-N-methylpyridinium)porphine (TMPyP) interactions with half-generation carboxyl-terminated poly(amidoamine) (PAMAM) dendrimers in water. TMPyP experiences a less polar environment and a strong fluorescence quenching effect upon dendrimer association. The tertiary amine functional groups in PAMAM dendrimers are likely to be responsible for the fluorescence quenching of TMPyP through an electron-transfer mechanism. The Stern-Volmer plots achieve a plateau at high dendrimer concentrations that was attributed to full porphyrin-dendrimer association, and an average fluorescence quantum yield of 15-20% relative to aqueous TMPyP was estimated. The association constant for the 1:1 complex with generation 2.5 at dendrimer-porphyrin ratio D/P = 1 is 5.75 x 10(7) M(-1), indicating a strong binding affinity. The dissociation of the complex with increasing ionic strength reinforces the role of electrostatic forces in porphyrin-dendrimer association. Comparison of Stern-Volmer plots obtained from quantum yields or lifetimes showed the importance of a static effect in these systems. The fluorescence decays of the porphyrin-dendrimer complex were fitted with a dispersed kinetics model. At intermediate dendrimer-porphyrin ratios (D/P approximately 1), diffusional quenching processes between free porphyrin and dendrimer were modeled with the Sano-Tachiya pair survival probability equation. Transient diffusional effects were dismissed as a possible explanation for the static effect detected.
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Affiliation(s)
- Pedro M R Paulo
- Centro de Química Estrutural, Complexo 1, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
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32
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Iavarone AT, Patriksson A, van der Spoel D, Parks JH. Fluorescence probe of Trp-cage protein conformation in solution and in gas phase. J Am Chem Soc 2007; 129:6726-35. [PMID: 17487969 DOI: 10.1021/ja065092s] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Measurements of protein unfolding in the absence of solvent, when combined with unfolding studies in solution, offer a unique opportunity to measure the effects of solvent on protein structure and dynamics. The experiments presented here rely on the fluorescence of an attached dye to probe the local conformational dynamics through interactions with a Trp residue and fields originating on charge sites. We present fluorescence measurements of thermal fluctuations accompanying conformational change of a miniprotein, Trp-cage, in solution and in gas phase. Molecular dynamics (MD) simulations are performed as a function of temperature, charge state, and charge location to elucidate the dye-protein conformational dynamics leading to the changes in measured fluorescence. The results indicate that the stability of the unsolvated protein is dominated by hydrogen bonds. Substituting asparagine for aspartic acid at position 9 results in a dramatic alteration of the solution unfolding curve, indicating that the salt bridge involving Lys8, Asp9, and Arg16 (+ - +) is essential for Trp-cage stability in solution. In contrast, this substitution results in minor changes in the unfolding curve of the unsolvated protein, showing that hydrogen bonds are the major contributor to the stability of Trp-cage in gas phase. Consistent with this hypothesis, the decrease in the number of hydrogen bonds with increasing temperature indicated by MD simulations agrees reasonably well with the experimentally derived enthalpies of conformational change. The simulation results display relatively compact conformations compared with NMR structures that are generally consistent with experimental results. The measured unfolding curves of unsolvated Trp-cage ions are invariant with the acetonitrile content of the solution from which they are formed, possibly as a result of conformational relaxation during or after desolvation. This work demonstrates the power of combined solution and gas-phase studies and of single-point mutations to identify specific noncovalent interactions which contribute to protein-fold stability. The combination of experiment and simulation is particularly useful because these approaches yield complementary information which can be used to deduce the details of structural changes of proteins in the gas phase.
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Affiliation(s)
- Anthony T Iavarone
- Rowland Institute at Harvard, 100 Edwin H. Land Boulevard, Cambridge, Massachusetts 02142, USA
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33
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Dvoranová D, Brezová V, Valko M, Staško A. Photoinduced transformation of camptothecin in the presence of iron(III) ions. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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34
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Benniston AC, Harriman A. Charge on the move: how electron-transfer dynamics depend on molecular conformation. Chem Soc Rev 2006; 35:169-79. [PMID: 16444298 DOI: 10.1039/b503169a] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This tutorial review illustrates the many facets whereby the molecular conformation helps to control the rates of through-bond electron transfer. A brief introduction to Marcus theory is given, highlighting the importance of the coupling element and the super-exchange mechanism, before considering the reasons why the coupling element might depend on the molecular geometry. The methods currently available for determination of both the coupling element and the geometry are reviewed and various examples are given for systems where the structure controls the degree of electronic coupling along the molecular axis. The role of the "bridge" connecting the donor and acceptor is emphasized.
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Affiliation(s)
- Andrew C Benniston
- Molecular Photonics Laboratory, School of Natural Sciences, Bedson Building, University of Newcastle, Newcastle upon Tyne, UK NE1 7RU.
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35
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Yao C, Kraatz HB, Steer RP. Photophysics of pyrene-labelled compounds of biophysical interest. Photochem Photobiol Sci 2004; 4:191-9. [PMID: 15696236 DOI: 10.1039/b414577c] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effects of the chemical constitution and structure of the substituent on the excited state dynamics of several model fluorescent pyrene-labelled molecules of biophysical interest have been examined. Nine new 1-substituted pyrenyl compounds, Py-NH-CO-C2H5, Py-NH-CO-Leu-Boc, Py-CH2-NH-CO-C2H5, Py-CH2-NH-CO-Leu-Boc, Py-CO-NH-C3H7, Py-CO-NH-Leu-OMe, Py-CH2-CO-NH-C3H7, Py-CH2-CO-NH-Leu-OMe and Py-C3H6-CO-NH-Leu-OMe, have been synthesized and their electronic spectra, fluorescence quantum yields and excited state lifetimes measured. These data have been used to calculate the radiative, kr, and non-radiative decay constants of their S1 states and the values of these constants correlated with the structures of the tethers. Non-radiative S1 decay rates (mainly intersystem crossing to T1) vary in parallel with the radiative rates so that the excited state lifetimes and radiative rate constants change considerably with the structure of the substituent whereas the quantum yields of fluorescence do not. An excellent correlation between [epsilon]max of the S1-S0 transition and either kr or the excited state lifetime is observed as long as no additional intermolecular or intramolecular excited state decay process of significant rate competes with the 'normal' radiative and non-radiative (ISC) decay processes of the pyrenyl chromophore. This correlation may have predictive value. Rates of bimolecular quenching of the S1 states of these molecules by molecular oxygen have been measured. The quenching process is diffusion-controlled with a spin statistical factor of 1, indicating that the S1-T1 electronic energy spacings of all the derivatives exceed the O2(1Deltag-3Sigmag-) electronic excitation energy of ca. 1 eV.
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Affiliation(s)
- Chunxiang Yao
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK, Canada S7N 5C9
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