1
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Zhang Z, Qian L, Zhang B, Ma C, Zhang G. Jellyfish-Inspired Polyurea Ionogel with Mechanical Robustness, Self-Healing, and Fluorescence Enabled by Hyperbranched Cluster Aggregates. Angew Chem Int Ed Engl 2024; 63:e202410335. [PMID: 38967098 DOI: 10.1002/anie.202410335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 07/04/2024] [Accepted: 07/05/2024] [Indexed: 07/06/2024]
Abstract
Ionogels are promising for soft iontronics, with their network structure playing a pivotal role in determining their performance and potential applications. However, simultaneously achieving mechanical toughness, low hysteresis, self-healing, and fluorescence using existing network structures is challenging. Drawing inspiration from jellyfish, we propose a novel hierarchical crosslinking network structure design for in situ formation of hyperbranched cluster aggregates (HCA) to fabricate polyurea ionogels to overcome these challenges. Leveraging the disparate reactivity of isocyanate groups, we induce the in situ formation of HCA through competing reactions, enhancing toughness and imparting the clustering-triggered emission of ionogel. This synergy between supramolecular interactions in the network and plasticizing effect in ionic liquid leads to reduced hysteresis of the ionogel. Furthermore, the incorporation of NCO-terminated prepolymer with dynamic oxime-urethane bonds (NPU) enables self-healing and enhances stretchability. Our investigations highlight the significant influence of HCA on ionogel performance, showcasing mechanical robustness including high strength (3.5 MPa), exceptional toughness (5.5 MJ m-3), resistance to puncture, and low hysteresis, self-healing, as well as fluorescence, surpassing conventional dynamic crosslinking approaches. This network design strategy is versatile and can meet the various demands of flexible electronics applications.
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Affiliation(s)
- Zhipeng Zhang
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Lu Qian
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Bin Zhang
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Chunfeng Ma
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Guangzhao Zhang
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China
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2
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Fang C, Rega N, Biczysko M. Editorial: Hot topic: excited state processes in biomolecules. Front Chem 2024; 12:1467074. [PMID: 39144700 PMCID: PMC11322346 DOI: 10.3389/fchem.2024.1467074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2024] [Accepted: 07/22/2024] [Indexed: 08/16/2024] Open
Affiliation(s)
- Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - Nadia Rega
- Department of Chemical Sciences, University of Napoli Federico II, Napoli, Italy
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3
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Johny M, Schouder CA, Al-Refaie A, He L, Wiese J, Stapelfeldt H, Trippel S, Küpper J. Water is a radiation protection agent for ionised pyrrole. Phys Chem Chem Phys 2024; 26:13118-13130. [PMID: 38629233 DOI: 10.1039/d3cp03471b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Radiation-induced damage of biological matter is an ubiquitous problem in nature. The influence of the hydration environment is widely discussed, but its exact role remains elusive. Utilising well defined solvated-molecule aggregates, we experimentally observed a hydrogen-bonded water molecule acting as a radiation protection agent for ionised pyrrole, a prototypical aromatic biomolecule. Pure samples of pyrrole and pyrrole(H2O) were outer-valence ionised and the subsequent damage and relaxation processes were studied. Bare pyrrole ions fragmented through the breaking of C-C or N-C covalent bonds. However, for pyrrole(H2O)+, we observed a strong protection of the pyrrole ring through the dissociative release of neutral water or by transferring an electron or proton across the hydrogen bond. Overall, a single water molecule strongly reduces the fragmentation probability and thus the persistent radiation damage of singly-ionised pyrrole.
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Affiliation(s)
- Melby Johny
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Constant A Schouder
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- LIDYL, CNRS, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Ahmed Al-Refaie
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
| | - Lanhai He
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
| | - Joss Wiese
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Chemistry, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Henrik Stapelfeldt
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Sebastian Trippel
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Jochen Küpper
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Chemistry, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
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4
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Li CY, Tian ZQ. Sixty years of electrochemical optical spectroscopy: a retrospective. Chem Soc Rev 2024; 53:3579-3605. [PMID: 38421335 DOI: 10.1039/d3cs00734k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Sixty years ago, Reddy, Devanatan, and Bockris performed the first in situ electrochemical ellipsometry experiment, which ushered in a new era in the study of electrochemistry, using optical spectroscopy. After six decades of development, electrochemical optical spectroscopy, particularly electrochemical vibrational spectroscopy, has advanced from a phase of immaturity with few methods and limited applications to a phase of maturity with excellent substrate generality and significantly improved resolutions. Here, we divide the development of electrochemical optical spectroscopy into four phases, focusing on the proof-of-concept of different electrochemical optical spectroscopy studies, the emergence of plasmonic enhancement-based electrochemical optical spectroscopic (in particular vibrational spectroscopic) methods, the realization of electrochemical vibrational spectroscopy on well-defined surfaces, and the efforts to achieve operando spectroelectrochemical applications. Finally, we discuss the future development trend of electrochemical optical spectroscopy, as well as examples of new methodology and research paradigms for operando spectroelectrochemistry.
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Affiliation(s)
- Chao-Yu Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
- School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China
| | - Zhong-Qun Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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5
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Lynch P, Das A, Alam S, Rich CC, Frontiera RR. Mastering Femtosecond Stimulated Raman Spectroscopy: A Practical Guide. ACS PHYSICAL CHEMISTRY AU 2024; 4:1-18. [PMID: 38283786 PMCID: PMC10811773 DOI: 10.1021/acsphyschemau.3c00031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 01/30/2024]
Abstract
Femtosecond stimulated Raman spectroscopy (FSRS) is a powerful nonlinear spectroscopic technique that probes changes in molecular and material structure with high temporal and spectral resolution. With proper spectral interpretation, this is equivalent to mapping out reactive pathways on highly anharmonic excited-state potential energy surfaces with femtosecond to picosecond time resolution. FSRS has been used to examine structural dynamics in a wide range of samples, including photoactive proteins, photovoltaic materials, plasmonic nanostructures, polymers, and a range of others, with experiments performed in multiple groups around the world. As the FSRS technique grows in popularity and is increasingly implemented in user facilities, there is a need for a widespread understanding of the methodology and best practices. In this review, we present a practical guide to FSRS, including discussions of instrumentation, as well as data acquisition and analysis. First, we describe common methods of generating the three pulses required for FSRS: the probe, Raman pump, and actinic pump, including a discussion of the parameters to consider when selecting a beam generation method. We then outline approaches for effective and efficient FSRS data acquisition. We discuss common data analysis techniques for FSRS, as well as more advanced analyses aimed at extracting small signals on a large background. We conclude with a discussion of some of the new directions for FSRS research, including spectromicroscopy. Overall, this review provides researchers with a practical handbook for FSRS as a technique with the aim of encouraging many scientists and engineers to use it in their research.
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Affiliation(s)
- Pauline
G. Lynch
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Aritra Das
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Shahzad Alam
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Christopher C. Rich
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Renee R. Frontiera
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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6
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Tutol J, Ong WSY, Phelps SM, Peng W, Goenawan H, Dodani SC. Engineering the ChlorON Series: Turn-On Fluorescent Protein Sensors for Imaging Labile Chloride in Living Cells. ACS CENTRAL SCIENCE 2024; 10:77-86. [PMID: 38292617 PMCID: PMC10823515 DOI: 10.1021/acscentsci.3c01088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/02/2023] [Accepted: 11/27/2023] [Indexed: 02/01/2024]
Abstract
Beyond its role as the "queen of electrolytes", chloride can also serve as an allosteric regulator or even a signaling ion. To illuminate this essential anion across such a spectrum of biological processes, researchers have relied on fluorescence imaging with genetically encoded sensors. In large part, these have been derived from the green fluorescent protein found in the jellyfish Aequorea victoria. However, a standalone sensor with a turn-on intensiometric response at physiological pH has yet to be reported. Here, we address this technology gap by building on our discovery of the anion-sensitive fluorescent protein mNeonGreen (mNG). The targeted engineering of two non-coordinating residues, namely K143 and R195, in the chloride binding pocket of mNG coupled with an anion walking screening and selection strategy resulted in the ChlorON sensors: ChlorON-1 (K143W/R195L), ChlorON-2 (K143R/R195I), and ChlorON-3 (K143R/R195L). In vitro spectroscopy revealed that all three sensors display a robust turn-on fluorescence response to chloride (20- to 45-fold) across a wide range of affinities (Kd ≈ 30-285 mM). We further showcase how this unique sensing mechanism can be exploited to directly image labile chloride transport with spatial and temporal resolution in a cell model overexpressing the cystic fibrosis transmembrane conductance regulator. Building from this initial demonstration, we anticipate that the ChlorON technology will have broad utility, accelerating the path forward for fundamental and translational aspects of chloride biology.
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Affiliation(s)
- Jasmine
N. Tutol
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Whitney S. Y. Ong
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Shelby M. Phelps
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Weicheng Peng
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Helen Goenawan
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Sheel C. Dodani
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
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7
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Wang Y, Wang D, Zhang S. Proton coupled isomerization in double-hydrogen-bonding-center salicylaldehyde azine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 304:123294. [PMID: 37659245 DOI: 10.1016/j.saa.2023.123294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 09/04/2023]
Abstract
The proton transfer dynamics of Schiff bases are of great importance due to the application potential. The excited state intramolecular proton transfer (ESIPT) of photochromic salicylaldehyde azine (SAA) in solutions was investigated by experimental and computational methods. Two distinguished spectral bands are observed in transient absorption spectra upon the photoexcitation with 400 nm. From the delayed stimulated emission signals, the ESIPT process is determined to be within <200 fs. Subsequently, the photoprotonated products undergo the vibrational relaxation with several picoseconds and the following isomerization with tens of picoseconds. These processes are significantly affected by the polarity of the solvents. The longest component with nanosecond scale can be explained to the relaxation to the enol structure. According to our observations, the SAA molecules with symmetric double-hydrogen-bonding-centers undergo single proton transfer rather than double proton transfer and subsequent intramolecular isomerization.
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Affiliation(s)
- Ye Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Dongdong Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Song Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
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8
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Krueger TD, Henderson JN, Breen IL, Zhu L, Wachter RM, Mills JH, Fang C. Capturing excited-state structural snapshots of evolutionary green-to-red photochromic fluorescent proteins. Front Chem 2023; 11:1328081. [PMID: 38144887 PMCID: PMC10748491 DOI: 10.3389/fchem.2023.1328081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 11/24/2023] [Indexed: 12/26/2023] Open
Abstract
Photochromic fluorescent proteins (FPs) have proved to be indispensable luminous probes for sophisticated and advanced bioimaging techniques. Among them, an interplay between photoswitching and photoconversion has only been observed in a limited subset of Kaede-like FPs that show potential for discovering the key mechanistic steps during green-to-red photoconversion. Various spectroscopic techniques including femtosecond stimulated Raman spectroscopy (FSRS), X-ray crystallography, and femtosecond transient absorption were employed on a set of five related FPs with varying photoconversion and photoswitching efficiencies. A 3-methyl-histidine chromophore derivative, incorporated through amber suppression using orthogonal aminoacyl tRNA synthetase/tRNA pairs, displays more dynamic photoswitching but greatly reduced photoconversion versus the least-evolved ancestor (LEA). Excitation-dependent measurements of the green anionic chromophore reveal that the varying photoswitching efficiencies arise from both the initial transient dynamics of the bright cis state and the final trans-like photoswitched off state, with an exocyclic bridge H-rocking motion playing an active role during the excited-state energy dissipation. This investigation establishes a close-knit feedback loop between spectroscopic characterization and protein engineering, which may be especially beneficial to develop more versatile FPs with targeted mutations and enhanced functionalities, such as photoconvertible FPs that also feature photoswitching properties.
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Affiliation(s)
- Taylor D. Krueger
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - J. Nathan Henderson
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Isabella L. Breen
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - Rebekka M. Wachter
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Jeremy H. Mills
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
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9
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Hutchison CDM, Baxter JM, Fitzpatrick A, Dorlhiac G, Fadini A, Perrett S, Maghlaoui K, Lefèvre SB, Cordon-Preciado V, Ferreira JL, Chukhutsina VU, Garratt D, Barnard J, Galinis G, Glencross F, Morgan RM, Stockton S, Taylor B, Yuan L, Romei MG, Lin CY, Marangos JP, Schmidt M, Chatrchyan V, Buckup T, Morozov D, Park J, Park S, Eom I, Kim M, Jang D, Choi H, Hyun H, Park G, Nango E, Tanaka R, Owada S, Tono K, DePonte DP, Carbajo S, Seaberg M, Aquila A, Boutet S, Barty A, Iwata S, Boxer SG, Groenhof G, van Thor JJ. Optical control of ultrafast structural dynamics in a fluorescent protein. Nat Chem 2023; 15:1607-1615. [PMID: 37563326 PMCID: PMC10624617 DOI: 10.1038/s41557-023-01275-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 06/12/2023] [Indexed: 08/12/2023]
Abstract
The photoisomerization reaction of a fluorescent protein chromophore occurs on the ultrafast timescale. The structural dynamics that result from femtosecond optical excitation have contributions from vibrational and electronic processes and from reaction dynamics that involve the crossing through a conical intersection. The creation and progression of the ultrafast structural dynamics strongly depends on optical and molecular parameters. When using X-ray crystallography as a probe of ultrafast dynamics, the origin of the observed nuclear motions is not known. Now, high-resolution pump-probe X-ray crystallography reveals complex sub-ångström, ultrafast motions and hydrogen-bonding rearrangements in the active site of a fluorescent protein. However, we demonstrate that the measured motions are not part of the photoisomerization reaction but instead arise from impulsively driven coherent vibrational processes in the electronic ground state. A coherent-control experiment using a two-colour and two-pulse optical excitation strongly amplifies the X-ray crystallographic difference density, while it fully depletes the photoisomerization process. A coherent control mechanism was tested and confirmed the wave packets assignment.
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Affiliation(s)
| | - James M Baxter
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Ann Fitzpatrick
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot, UK
| | - Gabriel Dorlhiac
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Alisia Fadini
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Samuel Perrett
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Karim Maghlaoui
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Salomé Bodet Lefèvre
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Violeta Cordon-Preciado
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Josie L Ferreira
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Volha U Chukhutsina
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Douglas Garratt
- Quantum Optics and Laser Science Group, Blackett Laboratory, Imperial College London, London, UK
| | - Jonathan Barnard
- Quantum Optics and Laser Science Group, Blackett Laboratory, Imperial College London, London, UK
| | - Gediminas Galinis
- Quantum Optics and Laser Science Group, Blackett Laboratory, Imperial College London, London, UK
| | - Flo Glencross
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Rhodri M Morgan
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Sian Stockton
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Ben Taylor
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Letong Yuan
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Matthew G Romei
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Chi-Yun Lin
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Jon P Marangos
- Quantum Optics and Laser Science Group, Blackett Laboratory, Imperial College London, London, UK
| | - Marius Schmidt
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Viktoria Chatrchyan
- Physikalisch Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Heidelberg, Germany
| | - Tiago Buckup
- Physikalisch Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Heidelberg, Germany
| | - Dmitry Morozov
- Nanoscience Center and Department of Chemistry, University of Jyväskylä, Jyväskylä, Finland
| | - Jaehyun Park
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
- Department of Chemical Engineering, POSTECH, Pohang, Republic of Korea
| | - Sehan Park
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
| | - Intae Eom
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
| | - Minseok Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
| | - Dogeun Jang
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
| | - Hyeongi Choi
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
| | - HyoJung Hyun
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
| | - Gisu Park
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
| | - Eriko Nango
- RIKEN SPring-8 Center, Sayo, Hyogo, Japan
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi, Japan
| | - Rie Tanaka
- RIKEN SPring-8 Center, Sayo, Hyogo, Japan
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Sakyo, Kyoto, Japan
| | - Shigeki Owada
- RIKEN SPring-8 Center, Sayo, Hyogo, Japan
- Japan Synchrotron Radiation Research Institute, Sayo, Hyogo, Japan
| | - Kensuke Tono
- RIKEN SPring-8 Center, Sayo, Hyogo, Japan
- Japan Synchrotron Radiation Research Institute, Sayo, Hyogo, Japan
| | - Daniel P DePonte
- Linac Coherent Light Source, Stanford Linear Accelerator Centre (SLAC), National Accelerator Laboratory, Menlo Park, CA, USA
| | - Sergio Carbajo
- Linac Coherent Light Source, Stanford Linear Accelerator Centre (SLAC), National Accelerator Laboratory, Menlo Park, CA, USA
| | - Matt Seaberg
- Linac Coherent Light Source, Stanford Linear Accelerator Centre (SLAC), National Accelerator Laboratory, Menlo Park, CA, USA
| | - Andrew Aquila
- Linac Coherent Light Source, Stanford Linear Accelerator Centre (SLAC), National Accelerator Laboratory, Menlo Park, CA, USA
| | - Sebastien Boutet
- Linac Coherent Light Source, Stanford Linear Accelerator Centre (SLAC), National Accelerator Laboratory, Menlo Park, CA, USA
| | - Anton Barty
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Hamburg, Germany
| | - So Iwata
- RIKEN SPring-8 Center, Sayo, Hyogo, Japan
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Sakyo, Kyoto, Japan
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Gerrit Groenhof
- Nanoscience Center and Department of Chemistry, University of Jyväskylä, Jyväskylä, Finland
| | - Jasper J van Thor
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, UK.
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10
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Krueger TD, Chen C, Fang C. Targeting Ultrafast Spectroscopic Insights into Red Fluorescent Proteins. Chem Asian J 2023; 18:e202300668. [PMID: 37682793 DOI: 10.1002/asia.202300668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/08/2023] [Accepted: 09/08/2023] [Indexed: 09/10/2023]
Abstract
Red fluorescent proteins (RFPs) represent an increasingly popular class of genetically encodable bioprobes and biomarkers that can advance next-generation breakthroughs across the imaging and life sciences. Since the rational design of RFPs with improved functions or enhanced versatility requires a mechanistic understanding of their working mechanisms, while fluorescence is intrinsically an ultrafast event, a suitable toolset involving steady-state and time-resolved spectroscopic techniques has become powerful in delineating key structural features and dynamic steps which govern irreversible photoconverting or reversible photoswitching RFPs, and large Stokes shift (LSS)RFPs. The pertinent cis-trans isomerization and protonation state change of RFP chromophores in their local environments, involving key residues in protein matrices, lead to rich and complicated spectral features across multiple timescales. In particular, ultrafast excited-state proton transfer in various LSSRFPs showcases the resolving power of wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) in mapping a photocycle with crucial knowledge about the red-emitting species. Moreover, recent progress in noncanonical RFPs with a site-specifically modified chromophore provides an appealing route for efficient engineering of redder and brighter RFPs, highly desirable for bioimaging. Such an effective feedback loop involving physical chemists, protein engineers, and biomedical microscopists will enable future successes to expand fundamental knowledge and improve human health.
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Affiliation(s)
- Taylor D Krueger
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
| | - Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
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11
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Tang L, Xu Y, Zhang W, Sui Y, Scida A, Tachibana SR, Garaga M, Sandstrom SK, Chiu NC, Stylianou KC, Greenbaum SG, Greaney PA, Fang C, Ji X. Strengthening Aqueous Electrolytes without Strengthening Water. Angew Chem Int Ed Engl 2023; 62:e202307212. [PMID: 37407432 DOI: 10.1002/anie.202307212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/11/2023] [Accepted: 07/05/2023] [Indexed: 07/07/2023]
Abstract
Aqueous electrolytes typically suffer from poor electrochemical stability; however, eutectic aqueous solutions-25 wt.% LiCl and 62 wt.% H3 PO4 -cooled to -78 °C exhibit a significantly widened stability window. Integrated experimental and simulation results reveal that, upon cooling, Li+ ions become less hydrated and pair up with Cl- , ice-like water clusters form, and H⋅⋅⋅Cl- bonding strengthens. Surprisingly, this low-temperature solvation structure does not strengthen water molecules' O-H bond, bucking the conventional wisdom that increasing water's stability requires stiffening the O-H covalent bond. We propose a more general mechanism for water's low temperature inertness in the electrolyte: less favorable solvation of OH- and H+ , the byproducts of hydrogen and oxygen evolution reactions. To showcase this stability, we demonstrate an aqueous Li-ion battery using LiMn2 O4 cathode and CuSe anode with a high energy density of 109 Wh/kg. These results highlight the potential of aqueous batteries for polar and extraterrestrial missions.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Yunkai Xu
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Weiyi Zhang
- Materials Science and Engineering, University of California, Riverside, CA, 92521, USA
| | - Yiming Sui
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Alexis Scida
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Sean R Tachibana
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Mounesha Garaga
- Hunter College, City University of New York, New York, NY, 10065, USA
| | - Sean K Sandstrom
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Nan-Chieh Chiu
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Kyriakos C Stylianou
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Steve G Greenbaum
- Hunter College, City University of New York, New York, NY, 10065, USA
| | - Peter Alex Greaney
- Materials Science and Engineering, University of California, Riverside, CA, 92521, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
| | - Xiulei Ji
- Department of Chemistry, Oregon State University, Corvallis, OR, 97331-4003, USA
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12
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Khoroshyy P, Martinez-Seara H, Myšková J, Lazar J. Dynamics of transition dipole moment orientation in representative fluorescent proteins. Phys Chem Chem Phys 2023; 25:22117-22123. [PMID: 37560975 DOI: 10.1039/d3cp01242e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Molecules of fluorescent proteins (FPs) exhibit distinct optical directionality. This optical directionality is characterized by transition dipole moments (TDMs), and their orientation with respect to the molecular structures. Although our recent observations of FP crystals allowed us to determine the mean TDM directions with respect to the framework of representative FP molecules, the dynamics of TDM orientations within FP molecules remain to be ascertained. Here we describe the results of our investigations of the dynamics of TDM directions in the fluorescent proteins eGFP, mTurquoise2 and mCherry, through time-resolved fluorescence polarization measurements and microsecond time scale all-atom molecular dynamics (MD) simulations. The investigated FPs exhibit initial fluorescence anisotropies (r0) consistent with significant differences in the orientation of the excitation and emission TDMs. However, based on MD data, we largely attribute this observation to rapid (sub-nanosecond) fluorophore motions within the FP molecular framework. Our results allow improved determinations of orientational distributions of FP molecules by polarization microscopy, as well as more accurate interpretations of fluorescence resonance energy transfer (FRET) observations.
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Affiliation(s)
- Petro Khoroshyy
- Inst. of Organic Chemistry and Biochemistry CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
- 1st Faculty of Medicine, Charles University, Albertov 4, 128 00, Prague 2, Czech Republic.
| | - Hector Martinez-Seara
- Inst. of Organic Chemistry and Biochemistry CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
| | - Jitka Myšková
- 1st Faculty of Medicine, Charles University, Albertov 4, 128 00, Prague 2, Czech Republic.
| | - Josef Lazar
- Inst. of Organic Chemistry and Biochemistry CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
- 1st Faculty of Medicine, Charles University, Albertov 4, 128 00, Prague 2, Czech Republic.
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13
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Chen L, He H, Huang X, Xu H, Yu Y. Control of the fluorescence molecule 2-(2'-hydroxyphenyl) benzothiazole derivatives by introducing electron-donating and withdrawing substituents groups. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 296:122666. [PMID: 37043917 DOI: 10.1016/j.saa.2023.122666] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 03/19/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
Using density functional theory (DFT) and time-dependent density functional theory (TDDFT), we investigate the fluorescence mechanism of (E)-4-(3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylstyryl)-1-methylpyridin-1-ium (HBTMY) and the excited-state intramolecular proton transfer process (ESIPT) of hydroxyphenyl. Herein, we introduce two electron-donating (amino and methoxy) and two electron-withdrawing (hydrogen and cyano) groups into HBTMY to study their effects on the fluorescence and the ESIPT process. Structural parameters, infrared vibration frequency, vertical excitation and emission energies as well as frontier molecular orbitals show that the substituents have different impacts on intramolecular hydrogen bonding behavior. The result shows that the fluorescence wavelength of molecules with the amino group could reach the near-infrared area, which favors using this fluorescence in the living cell. As the ability of electron-absorbing groups increases, the forward energy barrier in the potential energy curves decreases sharply making the ESIPT process more familiar to take place. Thus, this work offers a guide for cell imaging and provides strategies to adjust and control fluorescence by introducing substituents.
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Affiliation(s)
- Lu Chen
- College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Haixiang He
- College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China; Guangxi Key Laboratory of Electrochemical Energy Materials, Nanning 530004, PR China; Guangxi Colleges and Universities Key Laboratory of Applied Chemistry Technology and Resource Development, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China.
| | - Xindi Huang
- Guangxi Institute of Metrology and Test, Nanning 530004, PR China
| | - Honghong Xu
- College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Yan Yu
- College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
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14
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Chen C, Henderson JN, Ruchkin DA, Kirsh JM, Baranov MS, Bogdanov AM, Mills JH, Boxer SG, Fang C. Structural Characterization of Fluorescent Proteins Using Tunable Femtosecond Stimulated Raman Spectroscopy. Int J Mol Sci 2023; 24:11991. [PMID: 37569365 PMCID: PMC10418586 DOI: 10.3390/ijms241511991] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/19/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
The versatile functions of fluorescent proteins (FPs) as fluorescence biomarkers depend on their intrinsic chromophores interacting with the protein environment. Besides X-ray crystallography, vibrational spectroscopy represents a highly valuable tool for characterizing the chromophore structure and revealing the roles of chromophore-environment interactions. In this work, we aim to benchmark the ground-state vibrational signatures of a series of FPs with emission colors spanning from green, yellow, orange, to red, as well as the solvated model chromophores for some of these FPs, using wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) in conjunction with quantum calculations. We systematically analyzed and discussed four factors underlying the vibrational properties of FP chromophores: sidechain structure, conjugation structure, chromophore conformation, and the protein environment. A prominent bond-stretching mode characteristic of the quinoidal resonance structure is found to be conserved in most FPs and model chromophores investigated, which can be used as a vibrational marker to interpret chromophore-environment interactions and structural effects on the electronic properties of the chromophore. The fundamental insights gained for these light-sensing units (e.g., protein active sites) substantiate the unique and powerful capability of wavelength-tunable FSRS in delineating FP chromophore properties with high sensitivity and resolution in solution and protein matrices. The comprehensive characterization for various FPs across a colorful palette could also serve as a solid foundation for future spectroscopic studies and the rational engineering of FPs with diverse and improved functions.
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Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USA;
| | - J. Nathan Henderson
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; (J.N.H.); (J.H.M.)
| | - Dmitry A. Ruchkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ulitsa Miklukho-Maklaya, 16/10, 117997 Moscow, Russia; (D.A.R.); (M.S.B.); (A.M.B.)
| | - Jacob M. Kirsh
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA; (J.M.K.); (S.G.B.)
| | - Mikhail S. Baranov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ulitsa Miklukho-Maklaya, 16/10, 117997 Moscow, Russia; (D.A.R.); (M.S.B.); (A.M.B.)
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, 117997 Moscow, Russia
| | - Alexey M. Bogdanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ulitsa Miklukho-Maklaya, 16/10, 117997 Moscow, Russia; (D.A.R.); (M.S.B.); (A.M.B.)
| | - Jeremy H. Mills
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; (J.N.H.); (J.H.M.)
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Steven G. Boxer
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA; (J.M.K.); (S.G.B.)
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USA;
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15
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Chen C, Zhang H, Zhang J, Ai HW, Fang C. Structural origin and rational development of bright red noncanonical variants of green fluorescent protein. Phys Chem Chem Phys 2023; 25:15624-15634. [PMID: 37211909 PMCID: PMC10330862 DOI: 10.1039/d3cp01315d] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The incorporation of noncanonical amino acids (ncAAs) into fluorescent proteins is promising for red-shifting their fluorescence and benefiting tissue imaging with deep penetration and low phototoxicity. However, ncAA-based red fluorescent proteins (RFPs) have been rare. The 3-aminotyrosine modified superfolder green fluorescent protein (aY-sfGFP) represents a recent advance, yet the molecular mechanism for its red-shifted fluorescence remains elusive while its dim fluorescence hinders applications. Herein, we implement femtosecond stimulated Raman spectroscopy to obtain structural fingerprints in the electronic ground state and reveal that aY-sfGFP possesses a GFP-like instead of RFP-like chromophore. Red color of aY-sfGFP intrinsically arises from a unique "double-donor" chromophore structure that raises ground-state energy and enhances charge transfer, notably differing from the conventional conjugation mechanism. We further developed two aY-sfGFP mutants (E222H and T203H) with significantly improved (∼12-fold higher) brightness by rationally restraining the chromophore's nonradiative decay through electronic and steric effects, aided by solvatochromic and fluorogenic studies of the model chromophore in solution. This study thus provides functional mechanisms and generalizable insights into ncAA-RFPs with an efficient route for engineering redder and brighter fluorescent proteins.
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Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, USA.
| | - Hao Zhang
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA.
- Department of Molecular Physiology and Biological Physics and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Jing Zhang
- Department of Molecular Physiology and Biological Physics and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | - Hui-Wang Ai
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA.
- Department of Molecular Physiology and Biological Physics and Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
- The UVA Comprehensive Cancer Center, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, USA.
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16
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Xie J, Wang Z, Zhu R, Jiang J, Weng TC, Ren Y, Han S, Huang Y, Liu W. Investigation of Excited-State Intramolecular Proton Transfer and Structural Dynamics in Bis-Benzimidazole Derivative (BBM). Int J Mol Sci 2023; 24:ijms24119438. [PMID: 37298391 DOI: 10.3390/ijms24119438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
The bis-benzimidazole derivative (BBM) molecule, consisting of two 2-(2'-hydroxyphenyl) benzimidazole (HBI) halves, has been synthesized and successfully utilized as a ratiometric fluorescence sensor for the sensitive detection of Cu2+ based on enol-keto excited-state intramolecular proton transfer (ESIPT). In this study, we strategically implement femtosecond stimulated Raman spectroscopy and several time-resolved electronic spectroscopies, aided by quantum chemical calculations to investigate the detailed primary photodynamics of the BBM molecule. The results demonstrate that the ESIPT from BBM-enol* to BBM-keto* was observed in only one of the HBI halves with a time constant of 300 fs; after that, the rotation of the dihedral angle between the two HBI halves generated a planarized BBM-keto* isomer in 3 ps, leading to a dynamic redshift of BBM-keto* emission.
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Affiliation(s)
- Junhan Xie
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ziyu Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ruixue Zhu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jiaming Jiang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Tsu-Chien Weng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yi Ren
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shuhua Han
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan 250100, China
| | - Yifan Huang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Weimin Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
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17
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Liang K, Bi L, Zhu Q, Zhou H, Li S. Ultrafast Dynamics Revealed with Time-Resolved Scanning Tunneling Microscopy: A Review. ACS APPLIED OPTICAL MATERIALS 2023; 1:924-938. [PMID: 37260467 PMCID: PMC10227725 DOI: 10.1021/acsaom.2c00169] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/23/2023] [Indexed: 06/02/2023]
Abstract
A scanning tunneling microscope (STM) capable of performing pump-probe spectroscopy integrates unmatched atomic-scale resolution with high temporal resolution. In recent years, the union of electronic, terahertz, or visible/near-infrared pulses with STM has contributed to our understanding of the atomic-scale processes that happen between milliseconds and attoseconds. This time-resolved STM (TR-STM) technique is evolving into an unparalleled approach for exploring the ultrafast nuclear, electronic, or spin dynamics of molecules, low-dimensional structures, and material surfaces. Here, we review the recent advancements in TR-STM; survey its application in measuring the dynamics of three distinct systems, nucleus, electron, and spin; and report the studies on these transient processes in a series of materials. Besides the discussion on state-of-the-art techniques, we also highlight several emerging research topics about the ultrafast processes in nanoscale objects where we anticipate that the TR-STM can help broaden our knowledge.
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Affiliation(s)
- Kangkai Liang
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Liya Bi
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Qingyi Zhu
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
| | - Hao Zhou
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
| | - Shaowei Li
- Department
of Chemistry and Biochemistry, University
of California, San Diego, La Jolla, California 92093-0309, United States
- Materials
Science and Engineering Program, University
of California, San Diego, La Jolla, California 92093-0418, United States
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18
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Fresch E, Collini E. The Role of H-Bonds in the Excited-State Properties of Multichromophoric Systems: Static and Dynamic Aspects. Molecules 2023; 28:molecules28083553. [PMID: 37110786 PMCID: PMC10141795 DOI: 10.3390/molecules28083553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/12/2023] [Accepted: 04/15/2023] [Indexed: 04/29/2023] Open
Abstract
Given their importance, hydrogen bonds (H-bonds) have been the subject of intense investigation since their discovery. Indeed, H-bonds play a fundamental role in determining the structure, the electronic properties, and the dynamics of complex systems, including biologically relevant materials such as DNA and proteins. While H-bonds have been largely investigated for systems in their electronic ground state, fewer studies have focused on how the presence of H-bonds could affect the static and dynamic properties of electronic excited states. This review presents an overview of the more relevant progress in studying the role of H-bond interactions in modulating excited-state features in multichromophoric biomimetic complex systems. The most promising spectroscopic techniques that can be used for investigating the H-bond effects in excited states and for characterizing the ultrafast processes associated with their dynamics are briefly summarized. Then, experimental insights into the modulation of the electronic properties resulting from the presence of H-bond interactions are provided, and the role of the H-bond in tuning the excited-state dynamics and the related photophysical processes is discussed.
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Affiliation(s)
- Elisa Fresch
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Elisabetta Collini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
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19
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Solaris J, Krueger TD, Chen C, Fang C. Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red. Molecules 2023; 28:3506. [PMID: 37110741 PMCID: PMC10144053 DOI: 10.3390/molecules28083506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Proton transfer processes of organic molecules are key to charge transport and photoprotection in biological systems. Among them, excited-state intramolecular proton transfer (ESIPT) reactions are characterized by quick and efficient charge transfer within a molecule, resulting in ultrafast proton motions. The ESIPT-facilitated interconversion between two tautomers (PS and PA) comprising the tree fungal pigment Draconin Red in solution was investigated using a combination of targeted femtosecond transient absorption (fs-TA) and excited-state femtosecond stimulated Raman spectroscopy (ES-FSRS) measurements. Transient intensity (population and polarizability) and frequency (structural and cooling) dynamics of -COH rocking and -C=C, -C=O stretching modes following directed stimulation of each tautomer elucidate the excitation-dependent relaxation pathways, particularly the bidirectional ESIPT progression out of the Franck-Condon region to the lower-lying excited state, of the intrinsically heterogeneous chromophore in dichloromethane solvent. A characteristic overall excited-state PS-to-PA transition on the picosecond timescale leads to a unique "W"-shaped excited-state Raman intensity pattern due to dynamic resonance enhancement with the Raman pump-probe pulse pair. The ability to utilize quantum mechanics calculations in conjunction with steady-state electronic absorption and emission spectra to induce disparate excited-state populations in an inhomogeneous mixture of similar tautomers has broad implications for the modeling of potential energy surfaces and delineation of reaction mechanisms in naturally occurring chromophores. Such fundamental insights afforded by in-depth analysis of ultrafast spectroscopic datasets are also beneficial for future development of sustainable materials and optoelectronics.
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20
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Krueger TD, Tang L, Fang C. Delineating Ultrafast Structural Dynamics of a Green-Red Fluorescent Protein for Calcium Sensing. BIOSENSORS 2023; 13:bios13020218. [PMID: 36831983 PMCID: PMC9954042 DOI: 10.3390/bios13020218] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 05/14/2023]
Abstract
Fluorescent proteins (FPs) are indispensable tools for noninvasive bioimaging and sensing. Measuring the free cellular calcium (Ca2+) concentrations in vivo with genetically encodable FPs can be a relatively direct measure of neuronal activity due to the complex signaling role of these ions. REX-GECO1 is a recently developed red-green emission and excitation ratiometric FP-based biosensor that achieves a high dynamic range due to differences in the chromophore response to light excitation with and without calcium ions. Using steady-state electronic measurements (UV/Visible absorption and emission), along with time-resolved spectroscopic techniques including femtosecond transient absorption (fs-TA) and femtosecond stimulated Raman spectroscopy (FSRS), the potential energy surfaces of these unique biosensors are unveiled with vivid details. The ground-state structural characterization of the Ca2+-free biosensor via FSRS reveals a more spacious protein pocket that allows the chromophore to efficiently twist and reach a dark state. In contrast, the more compressed cavity within the Ca2+-bound biosensor results in a more heterogeneous distribution of chromophore populations that results in multi-step excited state proton transfer (ESPT) pathways on the sub-140 fs, 600 fs, and 3 ps timescales. These results enable rational design strategies to enlarge the spectral separation between the protonated/deprotonated forms and the Stokes shift leading to a larger dynamic range and potentially higher fluorescence quantum yield, which should be broadly applicable to the calcium imaging and biosensor communities.
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21
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Pu R, Wang Z, Zhu R, Jiang J, Weng TC, Huang Y, Liu W. Investigation of Ultrafast Configurational Photoisomerization of Bilirubin Using Femtosecond Stimulated Raman Spectroscopy. J Phys Chem Lett 2023; 14:809-816. [PMID: 36655842 DOI: 10.1021/acs.jpclett.2c03535] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Phototherapy is an efficient and safe way to reduce high levels of free 4Z,15Z-bilirubin (ZZ-BR) in the serum of newborns. The success of BR phototherapy lies in photoinduced configurational and structural isomerization processes that form excretable isomers. However, the physical picture of photoinduced photoisomerization of ZZ-BR is still unclear. Here, we strategically implement tunable femtosecond stimulated Raman spectroscopy and several time-resolved electronic spectroscopies, assisted by quantum chemical calculations, to dissect the detailed primary configurational isomerization dynamics of free ZZ-BR in organic solvents. The results of this study demonstrate that upon photoexcitation, ultrafast configurational isomerization proceeds by a volume-conserving "hula twist", followed by intramolecular hydrogen-bond distortion and large-scale rotation of the two dipyrrinone halves of the ZZ-BR isomer in a few picoseconds. After that, most of the population recovers back to ZZ-BR, and a very small amount is converted into stable BR isomers via structural isomerization.
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Affiliation(s)
- Ruihua Pu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
| | - Ziyu Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
| | - Ruixue Zhu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jiaming Jiang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Tsu-Chien Weng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yifan Huang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Weimin Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, China
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22
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Wang Z, Zhang Y, Chen C, Zhu R, Jiang J, Weng TC, Ji Q, Huang Y, Fang C, Liu W. Mapping the Complete Photocycle that Powers a Large Stokes Shift Red Fluorescent Protein. Angew Chem Int Ed Engl 2023; 62:e202212209. [PMID: 36440527 DOI: 10.1002/anie.202212209] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 11/29/2022]
Abstract
Large Stokes shift (LSS) red fluorescent proteins (RFPs) are highly desirable for bioimaging advances. The RFP mKeima, with coexisting cis- and trans-isomers, holds significance as an archetypal system for LSS emission due to excited-state proton transfer (ESPT), yet the mechanisms remain elusive. We implemented femtosecond stimulated Raman spectroscopy (FSRS) and various time-resolved electronic spectroscopies, aided by quantum calculations, to dissect the cis- and trans-mKeima photocycle from ESPT, isomerization, to ground-state proton transfer in solution. This work manifests the power of FSRS with global analysis to resolve Raman fingerprints of intermediate states. Importantly, the deprotonated trans-isomer governs LSS emission at 620 nm, while the deprotonated cis-isomer's 520 nm emission is weak due to an ultrafast cis-to-trans isomerization. Complementary spectroscopic techniques as a table-top toolset are thus essential to study photochemistry in physiological environments.
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Affiliation(s)
- Ziyu Wang
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Ya Zhang
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, 97331, Corvallis, OR, USA
| | - Ruixue Zhu
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Jiaming Jiang
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Tsu-Chien Weng
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Quanjiang Ji
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Yifan Huang
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, 97331, Corvallis, OR, USA
| | - Weimin Liu
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
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23
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Liu Y, Chaudhari AS, Chatterjee A, Andrikopoulos PC, Picchiotti A, Rebarz M, Kloz M, Lorenz-Fonfria VA, Schneider B, Fuertes G. Sub-Millisecond Photoinduced Dynamics of Free and EL222-Bound FMN by Stimulated Raman and Visible Absorption Spectroscopies. Biomolecules 2023; 13:161. [PMID: 36671546 PMCID: PMC9855911 DOI: 10.3390/biom13010161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/05/2023] [Accepted: 01/08/2023] [Indexed: 01/15/2023] Open
Abstract
Time-resolved femtosecond-stimulated Raman spectroscopy (FSRS) provides valuable information on the structural dynamics of biomolecules. However, FSRS has been applied mainly up to the nanoseconds regime and above 700 cm-1, which covers only part of the spectrum of biologically relevant time scales and Raman shifts. Here we report on a broadband (~200-2200 cm-1) dual transient visible absorption (visTA)/FSRS set-up that can accommodate time delays from a few femtoseconds to several hundreds of microseconds after illumination with an actinic pump. The extended time scale and wavenumber range allowed us to monitor the complete excited-state dynamics of the biological chromophore flavin mononucleotide (FMN), both free in solution and embedded in two variants of the bacterial light-oxygen-voltage (LOV) photoreceptor EL222. The observed lifetimes and intermediate states (singlet, triplet, and adduct) are in agreement with previous time-resolved infrared spectroscopy experiments. Importantly, we found evidence for additional dynamical events, particularly upon analysis of the low-frequency Raman region below 1000 cm-1. We show that fs-to-sub-ms visTA/FSRS with a broad wavenumber range is a useful tool to characterize short-lived conformationally excited states in flavoproteins and potentially other light-responsive proteins.
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Affiliation(s)
- Yingliang Liu
- Institute of Biotechnology of the Czech Academy of Sciences, 25250 Vestec, Czech Republic
- ELI Beamlines Facility Extreme Light Infrastructure ERIC, 25241 Dolni Brezany, Czech Republic
| | - Aditya S. Chaudhari
- Institute of Biotechnology of the Czech Academy of Sciences, 25250 Vestec, Czech Republic
- Faculty of Science, Charles University, 12800 Prague, Czech Republic
| | - Aditi Chatterjee
- Institute of Biotechnology of the Czech Academy of Sciences, 25250 Vestec, Czech Republic
- Faculty of Science, Charles University, 12800 Prague, Czech Republic
| | | | - Alessandra Picchiotti
- ELI Beamlines Facility Extreme Light Infrastructure ERIC, 25241 Dolni Brezany, Czech Republic
- The Hamburg Centre for Ultrafast Imaging, Hamburg University, 22761 Hamburg, Germany
| | - Mateusz Rebarz
- ELI Beamlines Facility Extreme Light Infrastructure ERIC, 25241 Dolni Brezany, Czech Republic
| | - Miroslav Kloz
- ELI Beamlines Facility Extreme Light Infrastructure ERIC, 25241 Dolni Brezany, Czech Republic
| | | | - Bohdan Schneider
- Institute of Biotechnology of the Czech Academy of Sciences, 25250 Vestec, Czech Republic
| | - Gustavo Fuertes
- Institute of Biotechnology of the Czech Academy of Sciences, 25250 Vestec, Czech Republic
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24
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Bailey-Darland S, Krueger TD, Fang C. Ultrafast Spectroscopies of Nitrophenols and Nitrophenolates in Solution: From Electronic Dynamics and Vibrational Structures to Photochemical and Environmental Implications. Molecules 2023; 28:601. [PMID: 36677656 PMCID: PMC9866910 DOI: 10.3390/molecules28020601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/27/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Nitrophenols are a group of small organic molecules with significant environmental implications from the atmosphere to waterways. In this work, we investigate a series of nitrophenols and nitrophenolates, with the contrasting ortho-, meta-, and para-substituted nitro group to the phenolic hydroxy or phenolate oxygen site (2/3/4NP or NP-), implementing a suite of steady-state and time-resolved spectroscopic techniques that include UV/Visible spectroscopy, femtosecond transient absorption (fs-TA) spectroscopy with probe-dependent and global analysis, and femtosecond stimulated Raman spectroscopy (FSRS), aided by quantum calculations. The excitation-dependent (400 and 267 nm) electronic dynamics in water and methanol, for six protonated or deprotonated nitrophenol molecules (three regioisomers in each set), enable a systematic investigation of the excited-state dynamics of these functional "nanomachines" that can undergo nitro-group twisting (as a rotor), excited-state intramolecular or intermolecular proton transfer (donor-acceptor, ESIPT, or ESPT), solvation, and cooling (chromophore) events on molecular timescales. In particular, the meta-substituted compound 3NP or 3NP- exhibits the strongest charge-transfer character with FSRS signatures (e.g., C-N peak frequency), and thus, does not favor nitroaromatic twist in the excited state, while the ortho-substituted compound 2NP can undergo ESIPT in water and likely generate nitrous acid (HONO) after 267 nm excitation. The delineated mechanistic insights into the nitro-substituent-location-, protonation-, solvent-, and excitation-wavelength-dependent effects on nitrophenols, in conjunction with the ultraviolet-light-induced degradation of 2NP in water, substantiates an appealing discovery loop to characterize and engineer functional molecules for environmental applications.
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25
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Addison K, Roy P, Bressan G, Skudaite K, Robb J, Bulman Page PC, Ashworth EK, Bull JN, Meech SR. Photophysics of the red-form Kaede chromophore. Chem Sci 2023; 14:3763-3775. [PMID: 37035701 PMCID: PMC10074405 DOI: 10.1039/d3sc00368j] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
The chromophore responsible for colour switching in the optical highlighting protein Kaede has unexpectedly complicated excited state dynamics, which are measured and analysed here. This will inform the development of new imaging proteins.
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Affiliation(s)
- Kiri Addison
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Palas Roy
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Giovanni Bressan
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Karolina Skudaite
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Josh Robb
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | | | - Eleanor K. Ashworth
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - James N. Bull
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Stephen R. Meech
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
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26
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dos Santos Rodrigues FH, Delgado GG, Santana da Costa T, Tasic L. Applications of fluorescence spectroscopy in protein conformational changes and intermolecular contacts. BBA ADVANCES 2023; 3:100091. [PMID: 37207090 PMCID: PMC10189374 DOI: 10.1016/j.bbadva.2023.100091] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023] Open
Abstract
Emission fluorescence is one of the most versatile and powerful biophysical techniques used in several scientific subjects. It is extensively applied in the studies of proteins, their conformations, and intermolecular contacts, such as in protein-ligand and protein-protein interactions, allowing qualitative, quantitative, and structural data elucidation. This review, aimed to outline some of the most widely used fluorescence techniques in this area, illustrate their applications and display a few examples. At first, the data on the intrinsic fluorescence of proteins is disclosed, mainly on the tryptophan side chain. Predominantly, research to study protein conformational changes, protein interactions, and changes in intensities and shifts of the fluorescence emission maximums were discussed. Fluorescence anisotropy or fluorescence polarization is a measurement of the changing orientation of a molecule in space, concerning the time between the absorption and emission events. Absorption and emission indicate the spatial alignment of the molecule's dipoles relative to the electric vector of the electromagnetic wave of excitation and emitted light, respectively. In other words, if the fluorophore population is excited with vertically polarized light, the emitted light will retain some polarization based on how fast it rotates in solution. Therefore, fluorescence anisotropy can be successfully used in protein-protein interaction investigations. Then, green fluorescent proteins (GFPs), photo-transformable fluorescent proteins (FPs) such as photoswitchable and photoconvertible FPs, and those with Large Stokes Shift (LSS) are disclosed in more detail. FPs are potent tools for the study of biological systems. Their versatility and wide range of colours and properties allow many applications. Finally, the application of fluorescence in life sciences is exposed, especially the application of FPs in fluorescence microscopy techniques with super-resolution that enables precise in vivo photolabeling to monitor the movement and interactions of target proteins.
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Affiliation(s)
| | - Gonzalo Garcia Delgado
- Chemical Biology Laboratory, Institute of Chemistry, Organic Chemistry Department, University of Campinas, P. O. Box 6154, Campinas 13083-970, SP, Brazil
| | - Thyerre Santana da Costa
- Chemical Biology Laboratory, Institute of Chemistry, Organic Chemistry Department, University of Campinas, P. O. Box 6154, Campinas 13083-970, SP, Brazil
| | - Ljubica Tasic
- Chemical Biology Laboratory, Institute of Chemistry, Organic Chemistry Department, University of Campinas, P. O. Box 6154, Campinas 13083-970, SP, Brazil
- Corresponding author: Ljubica Tasic: IQ, UNICAMP, Rua Josué de Castro sn, 13083-970 Campinas, SP, Brazil
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27
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Krueger TD, Tang L, Chen C, Zhu L, Breen IL, Wachter RM, Fang C. To twist or not to twist: From chromophore structure to dynamics inside engineered photoconvertible and photoswitchable fluorescent proteins. Protein Sci 2023; 32:e4517. [PMID: 36403093 PMCID: PMC9793981 DOI: 10.1002/pro.4517] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/31/2022] [Accepted: 11/15/2022] [Indexed: 11/21/2022]
Abstract
Green-to-red photoconvertible fluorescent proteins (FPs) are vital biomimetic tools for powerful techniques such as super-resolution imaging. A unique Kaede-type FP named the least evolved ancestor (LEA) enables delineation of the evolutionary step to acquire photoconversion capability from the ancestral green fluorescent protein (GFP). A key residue, Ala69, was identified through several steady-state and time-resolved spectroscopic techniques that allows LEA to effectively photoswitch and enhance the green-to-red photoconversion. However, the inner workings of this functional protein have remained elusive due to practical challenges of capturing the photoexcited chromophore motions in real time. Here, we implemented femtosecond stimulated Raman spectroscopy and transient absorption on LEA-A69T, aided by relevant crystal structures and control FPs, revealing that Thr69 promotes a stronger π-π stacking interaction between the chromophore phenolate (P-)ring and His193 in FP mutants that cannot photoconvert or photoswitch. Characteristic time constants of ~60-67 ps are attributed to P-ring twist as the onset for photoswitching in LEA (major) and LEA-A69T (minor) with photoconversion capability, different from ~16/29 ps in correlation with the Gln62/His62 side-chain twist in ALL-GFP/ALL-Q62H, indicative of the light-induced conformational relaxation preferences in various local environments. A minor subpopulation of LEA-A69T capable of positive photoswitching was revealed by time-resolved electronic spectroscopies with targeted light irradiation wavelengths. The unveiled chromophore structure and dynamics inside engineered FPs in an aqueous buffer solution can be generalized to improve other green-to-red photoconvertible FPs from the bottom up for deeper biophysics with molecular biology insights and powerful bioimaging advances.
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Affiliation(s)
| | - Longteng Tang
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Cheng Chen
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Liangdong Zhu
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Isabella L. Breen
- School of Molecular Sciences, Center for Bioenergy and Photosynthesis, Biodesign Center for Applied Structural DiscoveryArizona State UniversityTempeArizonaUSA
| | - Rebekka M. Wachter
- School of Molecular Sciences, Center for Bioenergy and Photosynthesis, Biodesign Center for Applied Structural DiscoveryArizona State UniversityTempeArizonaUSA
| | - Chong Fang
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
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28
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Direct or Indirect ESPT Mechanism in CFP psamFP488? A Theoretical-Computational Investigation. Int J Mol Sci 2022; 23:ijms232415640. [PMID: 36555282 PMCID: PMC9779432 DOI: 10.3390/ijms232415640] [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: 09/30/2022] [Revised: 11/27/2022] [Accepted: 12/02/2022] [Indexed: 12/14/2022] Open
Abstract
Fluorescent Proteins are widely studied for their multiple applications in technological and biotechnological fields. Despite this, they continue to represent a challenge in terms of a complete understanding of all the non-equilibrium photo-induced processes that rule their properties. In this context, a theoretical-computational approach can support experimental results in unveiling and understanding the processes taking place after electronic excitation. A non-standard cyan fluorescent protein, psamFP488, is characterized by an absorption maximum that is blue-shifted in comparison to other cyan fluorescent proteins. This protein is characterized by an extended Stokes shift and an ultrafast (170 fs) excited state proton transfer. In this work, a theoretical-computational study, including excited state ab initio dynamics, is performed to help understanding the reaction mechanism and propose new hypotheses on the role of the residues surrounding the chromophore. Our results suggest that the proton transfer could be indirect toward the acceptor (Glu167) and involves other residues surrounding the chromophore, despite the ultrafast kinetics.
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29
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Tang L, Bednar RM, Rozanov ND, Hemshorn ML, Mehl RA, Fang C. Rational Design for High Bioorthogonal Fluorogenicity of Tetrazine-Encoded Green Fluorescent Proteins. NATURAL SCIENCES (WEINHEIM, GERMANY) 2022; 2:e20220028. [PMID: 36440454 PMCID: PMC9699285 DOI: 10.1002/ntls.20220028] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The development of bioorthogonal fluorogenic probes constitutes a vital force to advance life sciences. Tetrazine-encoded green fluorescent proteins (GFPs) show high bioorthogonal reaction rate and genetic encodability, but suffer from low fluorogenicity. Here, we unveil the real-time fluorescence mechanisms by investigating two site-specific tetrazine-modified superfolder GFPs via ultrafast spectroscopy and theoretical calculations. Förster resonance energy transfer (FRET) is quantitatively modeled and revealed to govern the fluorescence quenching; for GFP150-Tet with a fluorescence turn-on ratio of ~9, it contains trimodal subpopulations with good (P1), random (P2), and poor (P3) alignments between the transition dipole moments of protein chromophore (donor) and tetrazine tag (Tet-v2.0, acceptor). By rationally designing a more free/tight environment, we created new mutants Y200A/S202Y to introduce more P2/P1 populations and improve the turn-on ratios to ~14/31, making the fluorogenicity of GFP150-Tet-S202Y the highest among all up-to-date tetrazine-encoded GFPs. In live eukaryotic cells, the GFP150-Tet-v3.0-S202Y mutant demonstrates notably increased fluorogenicity, substantiating our generalizable design strategy.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA
| | - Riley M. Bednar
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Sciences Building, Corvallis, Oregon 97331-7305, USA
| | - Nikita D. Rozanov
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA
| | - Marcus L. Hemshorn
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Sciences Building, Corvallis, Oregon 97331-7305, USA
| | - Ryan A. Mehl
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Sciences Building, Corvallis, Oregon 97331-7305, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA
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30
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Abstract
Surface-enhanced Raman spectroscopy (SERS) is a vibrational spectroscopy technique that enables specific identification of target analytes with sensitivity down to the single-molecule level by harnessing metal nanoparticles and nanostructures. Excitation of localized surface plasmon resonance of a nanostructured surface and the associated huge local electric field enhancement lie at the heart of SERS, and things will become better if strong chemical enhancement is also available simultaneously. Thus, the precise control of surface characteristics of enhancing substrates plays a key role in broadening the scope of SERS for scientific purposes and developing SERS into a routine analytical tool. In this review, the development of SERS substrates is outlined with some milestones in the nearly half-century history of SERS. In particular, these substrates are classified into zero-dimensional, one-dimensional, two-dimensional, and three-dimensional substrates according to their geometric dimension. We show that, in each category of SERS substrates, design upon the geometric and composite configuration can be made to achieve an optimized enhancement factor for the Raman signal. We also show that the temporal dimension can be incorporated into SERS by applying femtosecond pulse laser technology, so that the SERS technique can be used not only to identify the chemical structure of molecules but also to uncover the ultrafast dynamics of molecular structural changes. By adopting SERS substrates with the power of four-dimensional spatiotemporal control and design, the ultimate goal of probing the single-molecule chemical structural changes in the femtosecond time scale, watching the chemical reactions in four dimensions, and visualizing the elementary reaction steps in chemistry might be realized in the near future.
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Affiliation(s)
| | | | - Hai-Yao Yang
- School of Physics and Optoelectronics, South China University of Technology, Wushan Road 381, Guangzhou 510641, China
| | - Zhiyuan Li
- School of Physics and Optoelectronics, South China University of Technology, Wushan Road 381, Guangzhou 510641, China
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31
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Abstract
As an emerging optical imaging modality, stimulated Raman scattering (SRS) microscopy provides invaluable opportunities for chemical biology studies using its rich chemical information. Through rapid progress over the past decade, the development of Raman probes harnessing the chemical biology toolbox has proven to play a key role in advancing SRS microscopy and expanding biological applications. In this perspective, we first discuss the development of biorthogonal SRS imaging using small tagging of triple bonds or isotopes and highlight their unique advantages for metabolic pathway analysis and microbiology investigations. Potential opportunities for chemical biology studies integrating small tagging with SRS imaging are also proposed. We next summarize the current designs of highly sensitive and super-multiplexed SRS probes, as well as provide future directions and considerations for next-generation functional probe design. These rationally designed SRS probes are envisioned to bridge the gap between SRS microscopy and chemical biology research and should benefit their mutual development.
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Affiliation(s)
- Jiajun Du
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Haomin Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Lu Wei
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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32
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Boulanger SA, Chen C, Myasnyanko IN, Baranov MS, Fang C. Fluorescence Modulation of ortho-Green Fluorescent Protein Chromophores Following Ultrafast Proton Transfer in Solution. J Phys Chem B 2022; 126:5081-5093. [PMID: 35786966 DOI: 10.1021/acs.jpcb.2c03812] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photophysical and photochemical properties of the green fluorescent protein (GFP) chromophore and derivatives underlie their bioimaging applications. To date, ultrafast spectroscopic tools represent the key for unraveling fluorescence mechanisms toward rational design of this powerful biomimetic framework. To correlate the excited-state intramolecular proton transfer (ESIPT) with chromophore emission properties, we implement experimental and computational tool sets to elucidate real-time electronic and structural dynamics of two archetypal ortho-GFP chromophores (o-HBDI and o-LHBDI) possessing an intramolecular hydrogen bond to undergo efficient ESIPT, only differing in a bridge-bond constraint. Using excited-state femtosecond stimulated Raman spectroscopy (FSRS), a low-frequency phenolic (P)-ring-deformation mode (∼562 cm-1) was uncovered to accompany ESIPT. The tautomerized chromophore undergoes either rapid P-ring isomerization to reach the ground state with essentially no fluorescence for o-HBDI or enhanced (up to an impressive 180-fold in acetonitrile) and solvent-polarity-dependent fluorescence by P-ring locking in o-LHBDI. The significant dependence of the fluorescence enhancement ratio on solvent viscosity confirms P-ring isomerization as the dominant nonradiative decay pathway for o-HBDI. This work provides crucial insights into the dynamic solute-solvent electrostatic and steric interactions, enabling the application-specific improvement of ESIPT-capable molecules as versatile fluorescence-based sensors and imaging agents from large Stokes shift emission to brighter probes in physiological environments.
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Affiliation(s)
- Sean A Boulanger
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
| | - Ivan N Myasnyanko
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia.,Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia.,Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, United States
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33
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Tang L, Fang C. Photoswitchable Fluorescent Proteins: Mechanisms on Ultrafast Timescales. Int J Mol Sci 2022; 23:6459. [PMID: 35742900 PMCID: PMC9223536 DOI: 10.3390/ijms23126459] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 12/15/2022] Open
Abstract
The advancement of super-resolution imaging (SRI) relies on fluorescent proteins with novel photochromic properties. Using light, the reversibly switchable fluorescent proteins (RSFPs) can be converted between bright and dark states for many photocycles and their emergence has inspired the invention of advanced SRI techniques. The general photoswitching mechanism involves the chromophore cis-trans isomerization and proton transfer for negative and positive RSFPs and hydration-dehydration for decoupled RSFPs. However, a detailed understanding of these processes on ultrafast timescales (femtosecond to millisecond) is lacking, which fundamentally hinders the further development of RSFPs. In this review, we summarize the current progress of utilizing various ultrafast electronic and vibrational spectroscopies, and time-resolved crystallography in investigating the on/off photoswitching pathways of RSFPs. We show that significant insights have been gained for some well-studied proteins, but the real-time "action" details regarding the bidirectional cis-trans isomerization, proton transfer, and intermediate states remain unclear for most systems, and many other relevant proteins have not been studied yet. We expect this review to lay the foundation and inspire more ultrafast studies on existing and future engineered RSFPs. The gained mechanistic insights will accelerate the rational development of RSFPs with enhanced two-way switching rate and efficiency, better photostability, higher brightness, and redder emission colors.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA
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34
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Bin Mohd Yusof MS, Song H, Debnath T, Lowe B, Yang M, Loh ZH. Ultrafast proton transfer of the aqueous phenol radical cation. Phys Chem Chem Phys 2022; 24:12236-12248. [PMID: 35579397 DOI: 10.1039/d2cp00505k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Proton transfer (PT) reactions are fundamental to numerous chemical and biological processes. While sub-picosecond PT involving electronically excited states has been extensively studied, little is known about ultrafast PT triggered by photoionization. Here, we employ femtosecond optical pump-probe spectroscopy and quantum dynamics calculations to investigate the ultrafast proton transfer dynamics of the aqueous phenol radical cation (PhOH˙+). Analysis of the vibrational wave packet dynamics reveals unusually short dephasing times of 0.18 ± 0.02 ps and 0.16 ± 0.02 ps for the PhOH˙+ O-H wag and bend frequencies, respectively, suggestive of ultrafast PT occurring on the ∼0.1 ps timescale. The reduced potential energy surface obtained from ab initio calculations shows that PT is barrierless when it is coupled to the intermolecular hindered translation between PhOH˙+ and the proton-acceptor water molecule. Quantum dynamics calculations yield a lifetime of 193 fs for PhOH˙+, in good agreement with the experimental results and consistent with the PT reaction being mediated by the intermolecular O⋯O stretch. These results suggest that photoionization can be harnessed to produce photoacids that undergo ultrafast PT. In addition, they also show that PT can serve as an ultrafast deactivation channel for limiting the oxidative damage potential of radical cations.
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Affiliation(s)
- Muhammad Shafiq Bin Mohd Yusof
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Hongwei Song
- State Key Laboratory for Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Tushar Debnath
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Bethany Lowe
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Minghui Yang
- State Key Laboratory for Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
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35
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Twisted intramolecular charge transfer of nitroaromatic push-pull chromophores. Sci Rep 2022; 12:6557. [PMID: 35449231 PMCID: PMC9023442 DOI: 10.1038/s41598-022-10565-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/11/2022] [Indexed: 12/02/2022] Open
Abstract
The structural changes during the intramolecular charge transfer (ICT) of nitroaromatic chromophores, 4-dimethylamino-4′-nitrobiphenyl (DNBP) and 4-dimethylamino-4′-nitrostilbene (DNS) were investigated by femtosecond stimulated Raman spectroscopy (FSRS) with both high spectral and temporal resolutions. The kinetically resolved Raman spectra of DNBP and DNS in the locally-excited and charge-transferred states of the S1 state appear distinct, especially in the skeletal vibrational modes of biphenyl and stilbene including ν8a and νC=C. The ν8a of two phenyls and the νC=C of the central ethylene group (only for stilbene), which are strongly coupled in the planar geometries, are broken with the twist of nitrophenyl group with the ICT. Time-resolved vibrational spectroscopy measurements and the time-dependent density functional theory simulations support the ultrafast ICT dynamics of 220–480 fs with the twist of nitrophenyl group occurring in the S1 state of the nitroaromatic chromophores. While the ICT of DNBP occurs via a barrier-less pathway, the ICT coordinates of DNS are strongly coupled to several low-frequency out-of-phase deformation modes relevant to the twist of the nitrophenyl group.
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36
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Hostetter ER, Keyes JR, Poon I, Nguyen JP, Nite JM, Jimenez Hoyos CA, Smith CA. Prediction of Fluorophore Brightness in Designed Mini Fluorescence Activating Proteins. J Chem Theory Comput 2022; 18:3190-3203. [PMID: 35417158 DOI: 10.1021/acs.jctc.1c00748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The de novo computational design of proteins with predefined three-dimensional structure is becoming much more routine due to advancements both in force fields and algorithms. However, creating designs with functions beyond folding is more challenging. In that regard, the recent design of small beta barrel proteins that activate the fluorescence of an exogenous small molecule chromophore (DFHBI) is noteworthy. These proteins, termed mini fluorescence activating proteins (mFAPs), have been shown to increase the brightness of the chromophore more than 100-fold upon binding to the designed ligand pocket. The design process created a large library of variants with different brightness levels but gave no rational explanation for why one variant was brighter than another. Here, we use quantum mechanics and molecular dynamics simulations to investigate how molecular flexibility in the ground and excited states influences brightness. We show that the ability of the protein to resist dihedral angle rotation of the chromophore is critical for predicting brightness. Our simulations suggest that the mFAP/DFHBI complex has a rough energy landscape, requiring extensive ground-state sampling to achieve converged predictions of excited-state kinetics. While computationally demanding, this roughness suggests that mFAP protein function can be enhanced by reshaping the energy landscape toward conformations that better resist DFHBI bond rotation.
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Affiliation(s)
- Emma R Hostetter
- Department of Chemistry, Wesleyan University, 52 Lawn Ave, Middletown, Connecticut 06459, United States
| | - Jeffrey R Keyes
- Department of Chemistry, Wesleyan University, 52 Lawn Ave, Middletown, Connecticut 06459, United States
| | - Ivy Poon
- Department of Chemistry, Wesleyan University, 52 Lawn Ave, Middletown, Connecticut 06459, United States
| | - Justin P Nguyen
- Department of Chemistry, Wesleyan University, 52 Lawn Ave, Middletown, Connecticut 06459, United States
| | - Jacob M Nite
- Department of Chemistry, Wesleyan University, 52 Lawn Ave, Middletown, Connecticut 06459, United States
| | -
- Department of Chemistry, Wesleyan University, 52 Lawn Ave, Middletown, Connecticut 06459, United States
| | - Carlos A Jimenez Hoyos
- Department of Chemistry, Wesleyan University, 52 Lawn Ave, Middletown, Connecticut 06459, United States
| | - Colin A Smith
- Department of Chemistry, Wesleyan University, 52 Lawn Ave, Middletown, Connecticut 06459, United States
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37
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Nho HW, Adhikari A, Kwon OH. Ultrafast Excited-State Proton Transfer of a Cationic Superphotoacid in a Nanoscopic Water Pool. J Phys Chem B 2022; 126:1275-1283. [PMID: 35119852 DOI: 10.1021/acs.jpcb.1c09070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The excited-state proton transfer (ESPT) of a cationic superphotoacid, N-methyl-7-hydroxyquinolium, was studied within the water pool of an anionic aerosol-OT (AOT), bis(2-ethylhexyl) sulfosuccinate, reverse micelle (RM). Previously, we had found that the cationic photoacid residing at the anionic AOT interface was conducive to ESPT to the bound water having concentric heterogeneity on the time scale of hundreds of picoseconds to nanoseconds. In our present study, on the time scale of hundreds of femtoseconds to a few tens of picoseconds, the photoacid underwent an ultrafast ESPT influenced by mobile water constituting the core of the RM. The two subpopulations of the core water molecules that determine the ultrafast biphasic deprotonation of the photoacid on time scales differing by an order of magnitude were identified. The core water molecules solvating the counteranion of the photoacid showed a higher basicity than typical water clusters in bulk resulting in ESPT on a subpicosecond time scale. Bare water clusters sensed by the photoacid showed a slower ESPT, over several picoseconds, as typically limited by the rotational motion of water molecules for similar types of the photoacid.
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Affiliation(s)
- Hak-Won Nho
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.,Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Aniruddha Adhikari
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Oh-Hoon Kwon
- Department of Chemistry, College of Natural Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.,Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
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38
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Dobryakov AL, Krohn OA, Quick M, Ioffe I, Kovalenko SA. Positive and Negative Signal and Line-Shape in Stimulated Raman Spectroscopy: Resonance Femtosecond Raman Spectra of Diphenylbutadiene. J Chem Phys 2022; 156:084304. [DOI: 10.1063/5.0075116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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39
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Acid–base
reaction of a
super‐photoacid
with a cooperative amide
hydrogen‐bonded
chain. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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40
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Tang L, Fang C. Fluorescence Modulation by Ultrafast Chromophore Twisting Events: Developing a Powerful Toolset for Fluorescent-Protein-Based Imaging. J Phys Chem B 2021; 125:13610-13623. [PMID: 34883016 DOI: 10.1021/acs.jpcb.1c08570] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The advancement of modern life sciences has benefited tremendously from the discovery and development of fluorescent proteins (FPs), widely expressed in live cells to track a myriad of cellular events. The chromophores of various FPs can undergo many ultrafast photophysical and/or photochemical processes in the electronic excited state and emit fluorescence with different colors. However, the chromophore becomes essentially nonfluorescent in solution environment due to its intrinsic twisting capability upon photoexcitation. To study "microscopic" torsional events and their effects on "macroscopic" fluorescence, we have developed an integrated ultrafast characterization platform involving femtosecond transient absorption (fs-TA) and wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS). A wide range of naturally occurring, circularly permuted, non-canonical amino-acid-decorated FPs and FP-based optical highlighters with photochromicity, photoconversion, and/or photoswitching capabilities have been recently investigated in great detail. Twisting conformational motions were elucidated to exist in all of these systems but to various extents. The associated different ultrafast pathways can be monitored via frequency changes of characteristic Raman bands during primary events and functional processes. The mapped electronic and structural dynamics information is crucial and has shown great potential and initial success for the rational design of proteins and other photoreceptors with novel functions and fluorescence properties.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
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41
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Jeon K, Jen M, Lee S, Jang T, Pang Y. Intramolecular Charge Transfer of 1-Aminoanthraquinone and Ultrafast Solvation Dynamics of Dimethylsulfoxide. Int J Mol Sci 2021; 22:ijms222111926. [PMID: 34769357 PMCID: PMC8584543 DOI: 10.3390/ijms222111926] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 11/16/2022] Open
Abstract
The intramolecular charge transfer (ICT) of 1-aminoanthraquinone (AAQ) in the excited state strongly depends on its solvent properties, and the twisted geometry of its amino group has been recommended for the twisted ICT (TICT) state by recent theoretical works. We report the transient Raman spectra of AAQ in a dimethylsulfoxide (DMSO) solution by femtosecond stimulated Raman spectroscopy to provide clear experimental evidence for the TICT state of AAQ. The ultrafast (~110 fs) TICT dynamics of AAQ were observed from the major vibrational modes of AAQ including the νC-N + δCH and νC=O modes. The coherent oscillations in the vibrational bands of AAQ strongly coupled to the nuclear coordinate for the TICT process have been observed, which showed its anharmonic coupling to the low frequency out of the plane deformation modes. The vibrational mode of solvent DMSO, νS=O showed a decrease in intensity, especially in the hydrogen-bonded species of DMSO, which clearly shows that the solvation dynamics of DMSO, including hydrogen bonding, are crucial to understanding the reaction dynamics of AAQ with the ultrafast structural changes accompanying the TICT.
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42
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Liu T, Wang F, Wu Q, Chen T, Sun P. Fluorescent, electrically responsive and ultratough self-healing hydrogels via bioinspired all-in-one hierarchical micelles. MATERIALS HORIZONS 2021; 8:3096-3104. [PMID: 34515280 DOI: 10.1039/d1mh01172c] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Intelligent hydrogels that simultaneously exhibit excellent toughness, self-healing ability and photoelectronic responsiveness are in high demand but are greatly challenging to prepare. Inspired by the hierarchical structure of fluorescent proteins in jellyfish and biomembranes in nature, herein, a facile and universal all-in-one strategy is demonstrated to construct fluorescent, electrically responsive and ultratough self-healing hydrogels via aqueous self-assembly of polyelectrolyte-surfactant micelles with hierarchical structures and functionality. The self-assembled 2-ureido-4-[1H]-pyrimidone (UPy) hydrophobic core containing reversible physical crosslinks embedded in micelles leads to a durable network structure with excellent toughness and self-healing ability. Moreover, dramatically enhanced fluorescence emission is obtained due to the formation of nanoclusters with electron-rich moieties that show restricted intramolecular motion induced by hydrogen bonding networks from UPy dimer aggregation. The micelle-incorporated sulfonic acid groups mimic the function of biological membrane proteins that deftly control the micelle size, leading to electro-responsiveness, enhanced toughness and fluorescence emission.
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Affiliation(s)
- Tao Liu
- Key Laboratory of Functional Polymer Materials of Ministry of Education and College of Chemistry, and State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, China
| | - Fenfen Wang
- Key Laboratory of Functional Polymer Materials of Ministry of Education and College of Chemistry, and State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
| | - Qiang Wu
- Key Laboratory of Functional Polymer Materials of Ministry of Education and College of Chemistry, and State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
| | - Tiehong Chen
- School of Materials Science and Engineering & National Institute for Advanced Materials, Nankai University, Tianjin, China
| | - Pingchuan Sun
- Key Laboratory of Functional Polymer Materials of Ministry of Education and College of Chemistry, and State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
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43
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Boulanger SA, Chen C, Myasnyanko IN, Sokolov AI, Baranov MS, Fang C. Excited-State Dynamics of a meta-Dimethylamino Locked GFP Chromophore as a Fluorescence Turn-on Water Sensor †. Photochem Photobiol 2021; 98:311-324. [PMID: 34714942 DOI: 10.1111/php.13552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/19/2021] [Accepted: 10/26/2021] [Indexed: 12/14/2022]
Abstract
Strategic incorporation of a meta-dimethylamino (-NMe2 ) group on the conformationally locked green fluorescent protein (GFP) model chromophore (m-NMe2 -LpHBDI) has drastically altered molecular electronic properties, counterintuitively enhancing fluorescence of only the neutral and cationic chromophores in aqueous solution. A ˜200-fold decrease in fluorescence quantum yield of m-NMe2 -LpHBDI in alcohols (e.g., MeOH, EtOH and 2-PrOH) supports this GFP-derived compound as a fluorescence turn-on water sensor, with large fluorescence intensity differences between H2 O and ROH emissions in various H2 O/ROH binary mixtures. A combination of steady-state electronic spectroscopy, femtosecond transient absorption, ground-state femtosecond stimulated Raman spectroscopy (FSRS) and quantum calculations elucidates an intermolecular hydrogen-bonding chain between a solvent -OH group and the chromophore phenolic ring -NMe2 and -OH functional groups, wherein fluorescence differences arise from an extended hydrogen-bonding network beyond the first solvation shell, as opposed to fluorescence quenching via a dark twisted intramolecular charge-transfer state. The absence of a meta-NMe2 group twisting coordinate upon electronic excitation was corroborated by experiments on control samples without the meta-NMe2 group or with both meta-NMe2 and para-OH groups locked in a six-membered ring. These deep mechanistic insights stemming from GFP chromophore scaffold will enable rational design of organic, compact and environmentally friendly water sensors.
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Affiliation(s)
| | - Cheng Chen
- Department of Chemistry, Oregon State University, Corvallis, OR
| | - Ivan N Myasnyanko
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
| | - Anatolii I Sokolov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
| | - Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, OR
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44
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Bera K, Douglas CJ, Frontiera RR. Femtosecond stimulated Raman spectroscopy - guided library mining leads to efficient singlet fission in rubrene derivatives. Chem Sci 2021; 12:13825-13835. [PMID: 34760168 PMCID: PMC8549787 DOI: 10.1039/d1sc04251c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/22/2021] [Indexed: 12/04/2022] Open
Abstract
Chromophores undergoing singlet fission are promising candidates for harnessing solar energy as they can generate a pair of charge carriers by the absorption of one photon. However, photovoltaic devices employing singlet fission are still lacking practical applications due to the limitations within the existing molecules undergoing singlet fission. Chemical modifications to acenes can lead to efficient singlet fission devices, but the influence of changes to molecular structure on the rate of singlet fission is challenging to model and predict. Using femtosecond stimulated Raman spectroscopy we have previously demonstrated that the triplet separation process during singlet fission in crystalline rubrene is associated with the loss of electron density from its tetracene core. Based on this knowledge, we mined a library of new rubrene derivatives with electron withdrawing substituents that prime the molecules for efficient singlet fission, without impacting their crystal packing. Our rationally chosen crystalline chromophores exhibit significantly improved singlet fission rates. This study demonstrates the utility and strength of a structurally sensitive spectroscopic technique in providing insights to spectroscopy-guided materials selection and design guidelines that go beyond energy arguments to design new singlet fission-capable chromophores. In the race to find efficient singlet fission materials, picking a winner is not easy. Femtosecond stimulated Raman spectroscopy can help us choose the best candidates, as demonstrated here in choosing from a library of rubrene derivatives.![]()
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Affiliation(s)
- Kajari Bera
- Department of Chemistry, University of Minnesota Minneapolis MN 55455 USA +1612-624-2501
| | - Christopher J Douglas
- Department of Chemistry, University of Minnesota Minneapolis MN 55455 USA +1612-624-2501
| | - Renee R Frontiera
- Department of Chemistry, University of Minnesota Minneapolis MN 55455 USA +1612-624-2501
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45
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Pacini L, Lesieur C. A computational methodology to diagnose sequence-variant dynamic perturbations by comparing atomic protein structures. Bioinformatics 2021; 38:703-709. [PMID: 34694373 PMCID: PMC8574318 DOI: 10.1093/bioinformatics/btab736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 09/29/2021] [Accepted: 10/21/2021] [Indexed: 02/03/2023] Open
Abstract
MOTIVATION The objective is to diagnose dynamics perturbations caused by amino-acid mutations as prerequisite to assess protein functional health or drug failure, simply using network models of protein X-ray structures. RESULTS We find that the differences in the allocation of the atomic interactions of each amino acid to 1D, 2D, 3D, 4D structural levels between variants structurally robust, recover experimental dynamic perturbations. The allocation measure validated on two B-pentamers variants of AB5 toxins having 17 mutations, also distinguishes dynamic perturbations of pathogenic and non-pathogenic Transthyretin single-mutants. Finally, the main proteases of the coronaviruses SARS-CoV and SARS-CoV-2 exhibit changes in the allocation measure, raising the possibility of drug failure despite the main proteases structural similarity. AVAILABILITY AND IMPLEMENTATION The Python code used for the production of the results is available at github.com/lorpac/protein_partitioning_atomic_contacts. The authors will run the analysis on any PDB structures of protein variants upon request. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Lorenza Pacini
- AMPERE, CNRS, Université de Lyon, Lyon, 69622, France,Institut Rhônalpin des systèmes complexes (IXXI), École Normale Supérieure de Lyon, Lyon, 69007, France
| | - Claire Lesieur
- AMPERE, CNRS, Université de Lyon, Lyon, 69622, France,Institut Rhônalpin des systèmes complexes (IXXI), École Normale Supérieure de Lyon, Lyon, 69007, France,To whom correspondence should be addressed. E-mail:
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46
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Picconi D. Nonadiabatic quantum dynamics of the coherent excited state intramolecular proton transfer of 10-hydroxybenzo[h]quinoline. Photochem Photobiol Sci 2021; 20:1455-1473. [PMID: 34657277 DOI: 10.1007/s43630-021-00112-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/04/2021] [Indexed: 12/13/2022]
Abstract
The photoinduced nonadiabatic dynamics of the enol-keto isomerization of 10-hydroxybenzo[h]quinoline (HBQ) are studied computationally using high-dimensional quantum dynamics. The simulations are based on a diabatic vibronic coupling Hamiltonian, which includes the two lowest [Formula: see text] excited states and a [Formula: see text] state, which has high energy in the Franck-Condon zone, but significantly stabilizes upon excited state intramolecular proton transfer. A procedure, applicable to large classes of excited state proton transfer reactions, is presented to parametrize this model using potential energies, forces and force constants, which, in this case, are obtained by time-dependent density functional theory. The wave packet calculations predict a time scale of 10-15 fs for the photoreaction, and reproduce the time constants and the coherent oscillations observed in time-resolved spectroscopic studies performed on HBQ. In contrast to the interpretation given to the most recent experiments, it is found that the reaction initiated by [Formula: see text] photoexcitation proceeds essentially on a single potential energy surface, and the observed coherences bear signatures of Duschinsky mode-mixing along the reaction path. The dynamics after the [Formula: see text] excitation are instead nonadiabatic, and the [Formula: see text] state plays a major role in the relaxation process. The simulations suggest a mainly active role of the proton in the isomerization, rather than a passive migration assisted by the vibrations of the benzoquinoline backbone.
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Affiliation(s)
- David Picconi
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam-Golm, Germany.
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47
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Xu W, Wei L, Wang Z, Zhu R, Jiang J, Liu H, Du J, Weng TC, Zhang YB, Huang Y, Liu W. Tracking Ultrafast Fluorescence Switch-On and Color-Tuned Dynamics in Acceptor-Donor-Acceptor Chromophore. J Phys Chem B 2021; 125:10796-10804. [PMID: 34524821 DOI: 10.1021/acs.jpcb.1c05936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding how the conformational change of conjugated molecules with acceptor-donor-acceptor (A-D-A) architecture affects their physical and optoelectronic properties is critical for determining their ultimate performance in organic electronic devices. Here, we utilized femtosecond transient absorption, time-resolved upconversion photoluminescence spectroscopy, and tunable femtosecond-stimulated Raman spectroscopy, aided by quantum chemical calculations, to systematically investigate the excited state structural dynamics of the intramolecular charge transfer of the tetramethoxy anthracene-based fluorophore 2,3,6,7-tetramethoxy 9,10-dibenzaldehydeanthracene (AnDA) and its derivative 2,3,6,7-tetramethoxy 9,10-diphenylanthracene (TMDPAn) in chloroform. In the AnDA molecule, the tetramethoxy anthracene and benzaldehyde moieties exhibit a strong ability to donate and withdraw electrons. Upon photoexcitation, AnDA shows intriguing ultrafast fluorescence switch-on and red shift dynamics on charge transfer states, and the temporal evolution of AnDA recorded by ultrafast spectroscopy reveals a dynamic picture of two-step intramolecular charge transfer assisted by ultrafast conformational changes and solvation processes. Removing the aldehyde group from TMDPAn significantly decreases the electron pulling capacity of the phenyl unit and disables charge transfer characteristics.
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Affiliation(s)
- Wenqi Xu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China.,STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, People's Republic of China
| | - Lei Wei
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Zhengxin Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China.,STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, People's Republic of China
| | - Ruixue Zhu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Jiaming Jiang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Huiyan Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Juan Du
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Tsu-Chien Weng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Yue-Biao Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Yifan Huang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Weimin Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China.,STU and SIOM Joint Laboratory for Superintense Lasers and the Applications, Shanghai 201210, People's Republic of China
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48
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Chiariello MG, Donati G, Raucci U, Perrella F, Rega N. Structural Origin and Vibrational Fingerprints of the Ultrafast Excited State Proton Transfer of the Pyranine-Acetate Complex in Aqueous Solution. J Phys Chem B 2021; 125:10273-10281. [PMID: 34472354 DOI: 10.1021/acs.jpcb.1c05590] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The excited state proton transfer (ESPT) reaction from the photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS or pyranine) to an acetate molecule has been investigated in explicit aqueous solution via excited state ab initio molecular dynamics simulations based on hybrid quantum/molecular mechanics (QM/MM) potentials. In all the trajectories, the direct proton transfer has been observed in the excited state within 1 ps. We find that the initial structural configuration extracted from the ground state distribution strongly affects the ESPT kinetics. Indeed, the relative orientation of the proton donor-acceptor pair and the presence of a water molecule hydrogen bonded to the phenolic acid group of the pyranine are the key factors to facilitate the ESPT. Furthermore, we analyze the vibrational fingerprints of the ESPT reaction, reproducing the blue shift of the acetate CO stretching (COac), from 1666 to 1763 cm-1 testifying the transformation of acetate to acetic acid. Finally, our findings suggest that the acetate CC stretching (CCac) is also sensitive to the progress of the ESPT reaction. The CCac stretching is indeed ruled by the two vibrational modes (928 and 1426 cm-1), that in the excited state are alternately activated when the proton is shared or bound to the donor/acceptor, respectively.
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Affiliation(s)
- Maria Gabriella Chiariello
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Greta Donati
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Umberto Raucci
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Fulvio Perrella
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Nadia Rega
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Napoli, Italy.,CRIB Center for Advanced Biomaterials for Healthcare, Piazzale Tecchio, 80-80125 Napoli, Italy
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49
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Chen C, Tutol JN, Tang L, Zhu L, Ong WSY, Dodani SC, Fang C. Excitation ratiometric chloride sensing in a standalone yellow fluorescent protein is powered by the interplay between proton transfer and conformational reorganization. Chem Sci 2021; 12:11382-11393. [PMID: 34667546 PMCID: PMC8447875 DOI: 10.1039/d1sc00847a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
Natural and laboratory-guided evolution has created a rich diversity of fluorescent protein (FP)-based sensors for chloride (Cl−). To date, such sensors have been limited to the Aequorea victoria green fluorescent protein (avGFP) family, and fusions with other FPs have unlocked ratiometric imaging applications. Recently, we identified the yellow fluorescent protein from jellyfish Phialidium sp. (phiYFP) as a fluorescent turn-on, self-ratiometric Cl− sensor. To elucidate its working mechanism as a rare example of a single FP with this capability, we tracked the excited-state dynamics of phiYFP using femtosecond transient absorption (fs-TA) spectroscopy and target analysis. The photoexcited neutral chromophore undergoes bifurcated pathways with the twisting-motion-induced nonradiative decay and barrierless excited-state proton transfer. The latter pathway yields a weakly fluorescent anionic intermediate , followed by the formation of a red-shifted fluorescent state that enables the ratiometric response on the tens of picoseconds timescale. The redshift results from the optimized π–π stacking between chromophore Y66 and nearby Y203, an ultrafast molecular event. The anion binding leads to an increase of the chromophore pKa and ESPT population, and the hindrance of conversion. The interplay between these two effects determines the turn-on fluorescence response to halides such as Cl− but turn-off response to other anions such as nitrate as governed by different binding affinities. These deep mechanistic insights lay the foundation for guiding the targeted engineering of phiYFP and its derivatives for ratiometric imaging of cellular chloride with high selectivity. We discovered an interplay between proton transfer and conformational reorganization that powers a standalone fluorescent-protein-based excitation-ratiometric biosensor for chloride imaging.![]()
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Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Jasmine N Tutol
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Longteng Tang
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Whitney S Y Ong
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Chong Fang
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
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Boulanger SA, Chen C, Tang L, Zhu L, Baleeva NS, Myasnyanko IN, Baranov MS, Fang C. Shedding light on ultrafast ring-twisting pathways of halogenated GFP chromophores from the excited to ground state. Phys Chem Chem Phys 2021; 23:14636-14648. [PMID: 34212170 DOI: 10.1039/d1cp02140k] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Since green fluorescent protein (GFP) has revolutionized molecular and cellular biology for about three decades, there has been a keen interest in understanding, designing, and controlling the fluorescence properties of GFP chromophore (i.e., HBDI) derivatives from the protein matrix to solution. Amongst these cross-disciplinary efforts, the elucidation of excited-state dynamics of HBDI derivatives holds the key to correlating the light-induced processes and fluorescence quantum yield (FQY). Herein, we implement steady-state electronic spectroscopy, femtosecond transient absorption (fs-TA), femtosecond stimulated Raman spectroscopy (FSRS), and quantum calculations to study a series of mono- and dihalogenated HBDI derivatives (X = F, Cl, Br, 2F, 2Cl, and 2Br) in basic aqueous solution, gaining new insights into the photophysical reaction coordinates. In the excited state, the halogenated "floppy" chromophores exhibit an anti-heavy atom effect, reflected by strong correlations between FQY vs. Franck-Condon energy (EFC) or Stokes shift, and knrvs. EFC, as well as a swift bifurcation into the I-ring (major) and P-ring (minor) twisting motions. In the ground state, both ring-twisting motions become more susceptible to sterics and exhibit spectral signatures from the halogen-dependent hot ground-state absorption band decay in TA data. We envision this type of systematic analysis of the halogenated HBDI derivatives to provide guiding principles for the site-specific modification of GFP chromophores, and expand design space for brighter and potentially photoswitchable organic chemical probes in aqueous solution with discernible spectral signatures throughout the photocycle.
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Affiliation(s)
- Sean A Boulanger
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA.
| | - Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA.
| | - Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA.
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA.
| | - Nadezhda S Baleeva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia and Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Ivan N Myasnyanko
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia and Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, Moscow 117997, Russia and Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow 117997, Russia
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA.
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