1
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Yi HB, Lee S, Seo K, Kim H, Kim M, Lee HS. Cellular and Biophysical Applications of Genetic Code Expansion. Chem Rev 2024; 124:7465-7530. [PMID: 38753805 DOI: 10.1021/acs.chemrev.4c00112] [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: 05/18/2024]
Abstract
Despite their diverse functions, proteins are inherently constructed from a limited set of building blocks. These compositional constraints pose significant challenges to protein research and its practical applications. Strategically manipulating the cellular protein synthesis system to incorporate novel building blocks has emerged as a critical approach for overcoming these constraints in protein research and application. In the past two decades, the field of genetic code expansion (GCE) has achieved significant advancements, enabling the integration of numerous novel functionalities into proteins across a variety of organisms. This technological evolution has paved the way for the extensive application of genetic code expansion across multiple domains, including protein imaging, the introduction of probes for protein research, analysis of protein-protein interactions, spatiotemporal control of protein function, exploration of proteome changes induced by external stimuli, and the synthesis of proteins endowed with novel functions. In this comprehensive Review, we aim to provide an overview of cellular and biophysical applications that have employed GCE technology over the past two decades.
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Affiliation(s)
- Han Bin Yi
- Department of Chemistry, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Seungeun Lee
- Department of Chemistry, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Kyungdeok Seo
- Department of Chemistry, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Hyeongjo Kim
- Department of Chemistry, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Minah Kim
- Department of Chemistry, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
| | - Hyun Soo Lee
- Department of Chemistry, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
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2
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Feng RR, Wang M, Zhang W, Gai F. Unnatural Amino Acids for Biological Spectroscopy and Microscopy. Chem Rev 2024; 124:6501-6542. [PMID: 38722769 DOI: 10.1021/acs.chemrev.3c00944] [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: 05/23/2024]
Abstract
Due to advances in methods for site-specific incorporation of unnatural amino acids (UAAs) into proteins, a large number of UAAs with tailored chemical and/or physical properties have been developed and used in a wide array of biological applications. In particular, UAAs with specific spectroscopic characteristics can be used as external reporters to produce additional signals, hence increasing the information content obtainable in protein spectroscopic and/or imaging measurements. In this Review, we summarize the progress in the past two decades in the development of such UAAs and their applications in biological spectroscopy and microscopy, with a focus on UAAs that can be used as site-specific vibrational, fluorescence, electron paramagnetic resonance (EPR), or nuclear magnetic resonance (NMR) probes. Wherever applicable, we also discuss future directions.
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Affiliation(s)
- Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Manxi Wang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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3
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Ding L, Liu Y, Wang L, Yang Y. Distinguishing the responsive mechanisms of fluorescent probes to hydrogen peroxide, proteins, and DNA/RNA. Phys Chem Chem Phys 2024; 26:7765-7771. [PMID: 38372974 DOI: 10.1039/d4cp00082j] [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: 02/20/2024]
Abstract
The responsive mechanisms of cationic quinolinium-vinyl-N,N-dimethylaniline boronate (QVD-B) derivative probes to hydrogen peroxide (H2O2), proteins and DNA/RNA are theoretically investigated in this study. The potential energy curves of QVD-B scanned on a dihedral angle (N+-C-CC) in the first singlet (S1) state exhibit large torsional energy barriers. Additionally, the energy of the lowest unoccupied molecular orbital (LUMO) of an acceptor moiety (-3.14 eV) is lower than that of a donor moiety (-1.13 eV) in QVD-B. This demonstrates that photoinduced electron transfer (PET) quenches the fluorescence of QVD-B, as opposed to the previous report of intramolecular single-bond rotation. After reacting with H2O2, the reaction product of quinoline-vinyl-N,N-dimethylaniline (QVD) turns off the PET pathway and turns on the fluorescence at 550 nm, which is consistent with the experimental results (580 nm). Among the possible configurations of QVD-B that forms with proteins and DNA, the calculated fluorescence values of corresponding twisted QVD-B-P (638 nm) and QVD-B-D (686 nm) are consistent with the experimental results (632 and 688 nm). The frontier molecular orbital and electron-hole analysis show that the charge transfer distance follows the order of QVD (1.88 Å) < QVD-B-P (4.49 Å) < QVD-B-D (6.39 Å), which induces the fluorescence red-shifts of QVD-B-P and QVD-B-D compared to that of QVD. The multi-detection mechanism of the fluorescent probe QVD-B is attributed to PET progress and different degrees of local charge transfer after photoexcitation.
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Affiliation(s)
- Lina Ding
- School of Chemistry and Chemical Engineering, School of Physics, Henan Normal University, Xinxiang 453007, P. R. China.
| | - Yang Liu
- School of Chemistry and Chemical Engineering, School of Physics, Henan Normal University, Xinxiang 453007, P. R. China.
| | - Liang Wang
- School of Chemistry and Chemical Engineering, School of Physics, Henan Normal University, Xinxiang 453007, P. R. China.
| | - Yonggang Yang
- School of Chemistry and Chemical Engineering, School of Physics, Henan Normal University, Xinxiang 453007, P. R. China.
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4
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Abou-Hatab S, Matsika S. Excited state hydrogen or proton transfer pathways in microsolvated n-cyanoindole fluorescent probes. Phys Chem Chem Phys 2024; 26:4511-4523. [PMID: 38240574 DOI: 10.1039/d3cp04844f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The sensitivity of the fluorescence properties of n-cyanoindole (n-CNI) fluorescent probes to the microenvironment makes them potential reporters of protein conformation and hydration. The fluorescence intensity of 5-CNI, 6-CNI, and 7-CNI is quenched when exposed to water solvent whereas substitution on position 4 of indoles dramatically increases it. A potential mechanism for this sensitivity to water may be similar to that found in indole. The fluorescence of indole is found to be quenched when interacting with water and ammonia solvent molecules via radiationless decay through an S1 (πσ*)/S0 conical intersection caused by excited state proton or hydrogen transfer to the solvent molecules. In this study we examine this fluorescence quenching mechanism along the N-H bond stretch of n-CNI probes using water cluster models and quantum mechanical calculations of the excited states. We find that n-CNI-(H2O)1-2 clusters form cyclic or non-cyclic structures via hydrogen bonds which lead to different photochemical reaction paths that can potentially quench the fluorescence by undergoing internal conversion from S1 to S0. However, the existence of a high energy barrier along the potential energy surface of the S1 state in most cases prevents this from occurring. We show that substitution on position 4 leads to the highest energy barrier that prevents the fluorophore from accessing these non-radiative channels, in agreement with its high intensity. We also find that the energy barrier in the S1 state of non-cyclic 5-CNI-(H2O)1-2 excited complexes decreases as the number of water molecules increases, which suggests great sensitivity of the fluorescence quenching on the aqueous environment.
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5
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Dodds AC, Sansom HG, Magennis SW, Sutherland A. Synthesis of Thiazoloindole α-Amino Acids: Chromophores Amenable to One- and Two-Photon Induced Fluorescence. Org Lett 2023; 25:8942-8946. [PMID: 38055619 PMCID: PMC10729019 DOI: 10.1021/acs.orglett.3c03851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/02/2023] [Accepted: 12/05/2023] [Indexed: 12/08/2023]
Abstract
Thiazoloindole α-amino acids have been synthesized in four steps from tryptophan using a dual-catalytic thiolation reaction and a copper-mediated intramolecular N-arylation process. Late-stage diversification of the thiazoloindole core with electron-deficient aryl substituents produced chromophores that on one-photon excitation displayed blue-green emission, mega-Stokes shifts, and high quantum yields. The thiazoloindole amino acids could also be excited via two-photon absorption in the near-infrared, demonstrating their potential for biomedical imaging applications.
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Affiliation(s)
- Amy C. Dodds
- School of Chemistry, The Joseph Black
Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Henry G. Sansom
- School of Chemistry, The Joseph Black
Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Steven W. Magennis
- School of Chemistry, The Joseph Black
Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Andrew Sutherland
- School of Chemistry, The Joseph Black
Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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6
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Passow KT, Harki DA. 4-Isocyanoindole-2'-deoxyribonucleoside (4ICIN): An Isomorphic Indole Nucleoside Suitable for Inverse Electron Demand Diels-Alder Reactions. Tetrahedron Lett 2023; 132:154807. [PMID: 38009110 PMCID: PMC10673620 DOI: 10.1016/j.tetlet.2023.154807] [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] [Indexed: 11/28/2023]
Abstract
Isomorphic nucleosides are powerful tool compounds for interrogating a variety of biological processes involving nucleosides and nucleic acids. We previously reported a fluorescent isomorphic indole nucleoside called 4CIN. A distinguishing molecular feature of 4CIN is the presence of a 4-cyano moiety on the indole that functions as the nucleobase. Given the known chemical reactivity of isonitriles with tetrazines through [4+1]-cycloaddition chemistry, we investigated whether conversion of 4CIN to the corresponding isonitrile would confer a useful chemical probe. Here we report the synthesis of 4-isocyanoindole-2'-deoxyribonucleoside (4ICIN) and the propensity of 4ICIN to undergo inverse electron demand Diels-Alder cycloaddition with a model tetrazine.
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Affiliation(s)
- Kellan T Passow
- Department of Medicinal Chemistry, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, United States
| | - Daniel A Harki
- Department of Medicinal Chemistry, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, United States
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7
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You M, Gao Z, Zhou L, Guo C, Guo Q. Investigation of the Vibrational Characteristics of 6-Isocyano-1-Methyl-1H-Indole: Utilizing the Isonitrile Group as an Infrared Probe. Molecules 2023; 28:6939. [PMID: 37836782 PMCID: PMC10574170 DOI: 10.3390/molecules28196939] [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: 09/14/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Indole derivatives have garnered considerable attention in the realm of biochemistry due to their multifaceted properties. In this study, we undertake a systematic investigation of the vibrational characteristics of a model indole derivative, 6-isocyano-1-methyl-1H-indole (6ICMI), by employing a combination of FTIR, IR pump-probe spectroscopy, and theoretical calculations. Our findings demonstrate a strong dependence of the isonitrile stretching frequency of 6ICMI on the polarizability of protic solvents and the density of hydrogen-bond donor groups in the solvent when the isonitrile group is bonded to aromatic groups. Both experimental and theoretical analyses unveil a significant correlation between the isonitrile stretch vibration of 6ICMI and the solvent acceptor number of alcohols. Furthermore, the polarization-controlled infrared pump-probe conducted on 6ICMI in dimethyl sulfoxide provides additional support for the potential use of the isonitrile stretching mode of 6ICMI as an effective infrared probe for local environments.
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Affiliation(s)
- Min You
- School of Computer Science and Engineering, Chongqing Three Gorges University, Wanzhou, Chongqing 404100, China
| | - Zilin Gao
- School of Computer Science and Engineering, Chongqing Three Gorges University, Wanzhou, Chongqing 404100, China
| | - Liang Zhou
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China;
| | - Changyuan Guo
- Key Laboratory of Intelligent Air-Ground Cooperative Control for Universities in Chongqing, College of Automation, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Qiang Guo
- Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, School of Chemistry and Chemical Engineering, North University of China, Taiyuan 030051, China
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8
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Songsri S, Harkiss AH, Sutherland A. Synthesis and Photophysical Properties of Charge-Transfer-Based Pyrimidine-Derived α-Amino Acids. J Org Chem 2023; 88:13214-13224. [PMID: 37621156 PMCID: PMC10507667 DOI: 10.1021/acs.joc.3c01437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Indexed: 08/26/2023]
Abstract
The four-step synthesis of fluorescent pyrimidine-derived α-amino acids from an l-aspartic acid derivative is described. The key synthetic steps involved preparation of ynone intermediates via the reaction of alkynyl lithium salts with a Weinreb amide, followed by an ytterbium-catalyzed heterocyclization reaction with amidines. Variation of substituents at the C2- and C4-position of the pyrimidine ring allowed tuning of the photoluminescent properties of the α-amino acids. This revealed that a combination of highly conjugated or electron-rich aryl substituents with the π-deficient pyrimidine motif resulted in fluorophores with the highest quantum yields and overall brightness. Further analysis of the most fluorogenic α-amino acid demonstrated solvatochromism and sensitivity to pH.
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Affiliation(s)
- Sineenard Songsri
- School of Chemistry, The Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Alexander H. Harkiss
- School of Chemistry, The Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Andrew Sutherland
- School of Chemistry, The Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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9
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Bartolucci S, Retini M, Fanini F, Paderni D, Piersanti G. Synthesis and Fluorescence Properties of 4-Cyano and 4-Formyl Melatonin as Putative Melatoninergic Ligands. ACS OMEGA 2023; 8:22190-22194. [PMID: 37360469 PMCID: PMC10286092 DOI: 10.1021/acsomega.3c02518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023]
Abstract
Fluorescent ligands are imperative to many facets of chemical biology and medicinal chemistry. Herein, we report the syntheses of two fluorescent melatonin-based derivatives as potential ligands of melatonin receptors. The two compounds, namely, 4-cyano and 4-formyl melatonin (4CN-MLT and 4CHO-MLT, respectively), which differ from melatonin by only two/three atoms that are very compact in size, were prepared using the selective C3-alkylation of indoles with N-acetyl ethanolamines involving the "borrowing hydrogen" strategy. These compounds exhibit absorption/emission spectra that are red-shifted from those of melatonin. Binding studies on two melatonin receptor subtypes showed that these derivatives have a modest affinity and selectivity ratio.
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Affiliation(s)
- Silvia Bartolucci
- Department
of Biomolecular Sciences, University of
Urbino Carlo Bo, Piazza del Rinascimento 6, 61029 Urbino, Pesaro and Urbino, Italy
| | - Michele Retini
- Department
of Biomolecular Sciences, University of
Urbino Carlo Bo, Piazza del Rinascimento 6, 61029 Urbino, Pesaro and Urbino, Italy
| | - Fabiola Fanini
- Department
of Biomolecular Sciences, University of
Urbino Carlo Bo, Piazza del Rinascimento 6, 61029 Urbino, Pesaro and Urbino, Italy
| | - Daniele Paderni
- Department
of Pure and Applied Sciences, University
of Urbino Carlo Bo, Via della Stazione 4, 61029 Urbino, Pesaro and Urbino, Italy
| | - Giovanni Piersanti
- Department
of Biomolecular Sciences, University of
Urbino Carlo Bo, Piazza del Rinascimento 6, 61029 Urbino, Pesaro and Urbino, Italy
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10
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Yuan Y, Liu J, Feng RR, Zhang W, Gai F. Photophysics of Two Indole-Based Cyan Fluorophores. J Phys Chem B 2023; 127:4508-4513. [PMID: 37171997 DOI: 10.1021/acs.jpcb.3c01739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
For the purpose of searching for new biological fluorophore, we assess the photophysical properties of two indole derivatives, 4-cyano-7-azaindole (4CN7AI) and 1-methyl-4-cyano-7-azaindole (1M4CN7AI), in a series of solvents. We find that (1) the absorption spectra of both derivatives are insensitive to solvents and are red-shifted from that of indole, having a maximum absorption wavelength of ca. 318 nm and a broad profile that extends beyond 370 nm; (2) both derivatives emit in the blue to green spectral range with a large Stokes shift, for example, in H2O, the maximum emission wavelength of 4CN7AI (1M4CN7AI) is at ca. 455 nm (470 nm); (3) 4CN7AI has a higher fluorescence quantum yield (QY) and a longer fluorescence lifetime (τF) in aprotic solvents than in protic solvents, for example, QY (τF) = 0.72 ± 0.04 (7.6 ± 0.8 ns) in tetrahydrofuran and QY (τF) = 0.29 ± 0.03 (6.2 ± 0.6 ns) in H2O; (4) in all of the solvents used except H2O, the fluorescence QY (τF) of 1M4CN7AI is equal to or higher (longer) than 0.69 ± 0.03 (11.2 ± 0.7 ns). Taken together, these results suggest that the corresponding non-natural amino acids, 4-cyano-7-azatryptophan and 1-methyl-4-cyano-7-azatryptophan, could be useful as biological fluorophores.
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Affiliation(s)
- Yu Yuan
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jingsong Liu
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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11
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Riley L, Mclay TN, Sutherland A. Synthesis and Fluorescent Properties of Alkynyl- and Alkenyl-Fused Benzotriazole-Derived α-Amino Acids. J Org Chem 2023; 88:2453-2463. [PMID: 36749161 PMCID: PMC9942204 DOI: 10.1021/acs.joc.2c02886] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Fluorescent unnatural α-amino acids are widely used as probes in chemical biology and medicinal chemistry. While a variety of structural classes have been developed, there is still a requirement for new environmentally sensitive analogues that can closely mimic proteinogenic α-amino acids. Here, we report the synthesis and fluorescent properties of highly conjugated, benzotriazole-derived α-amino acids designed to mimic l-tryptophan. Alkynyl-substituted analogues were prepared using three key steps, nucleophilic aromatic substitution with a 3-aminoalanine derivative, benzotriazole formation via a one-pot diazotization and cyclization process, and a Sonogashira cross-coupling reaction. E-Alkenyl-substituted benzotriazoles were accessed by stereoselective partial hydrogenation of the alkynes using zinc iodide and palladium catalysis. The alkynyl analogues were found to possess higher quantum yields and stronger brightness and, a solvatochromic study with the most fluorogenic α-amino acids demonstrated sensitivity to polarity.
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12
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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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13
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Haldar T, Chatterjee S, Alam MN, Maity P, Bagchi S. Blue Fluorescence of Cyano-tryptophan Predicts Local Electrostatics and Hydrogen Bonding in Biomolecules. J Phys Chem B 2022; 126:10732-10740. [PMID: 36511763 DOI: 10.1021/acs.jpcb.2c05848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cyano-tryptophan is an unnatural fluorescent amino acid that emits in the visible region. Along with the structural similarity with tryptophan, the unique photophysical properties of this fluorophore make it an ideal probe for biophysical research. Herein, combining fluorescence spectroscopy, infrared spectroscopy, and molecular dynamics simulations, we show that the cyano-tryptophan's emission energy quantifies the underlying bond-specific noncovalent interactions in terms of the electric field. We further report the use of fluorophore's emission energy to predict its hydrogen bond characteristics. We demonstrate that combining experiments with molecular dynamics simulations can provide the hydrogen bonding status of the nitrile moiety. In addition, we report a method to differentiate between aqueous and nonaqueous hydrogen-bonding partners. Using a phenomenological approach, we demonstrate that the presence of the cyano-indole moiety is responsible for the distinct correlations between the fluorophore's emission and the electrostatic forces on the nitrile bond. As indole is a privileged scaffold for both native amino acids and nucleobases, cyano-indoles will have many multifaceted applications.
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Affiliation(s)
- Tapas Haldar
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Srijan Chatterjee
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Md Nirshad Alam
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Pradip Maity
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Sayan Bagchi
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
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14
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Morshedi M, Nolden O, Janke P, Haselbach W, Schmitt M, Gilch P. The photophysics of 2-cyanoindole probed by femtosecond spectroscopy. Photochem Photobiol Sci 2022; 22:745-759. [PMID: 36495408 DOI: 10.1007/s43630-022-00348-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/24/2022] [Indexed: 12/14/2022]
Abstract
AbstractThe photophysics of 2-cyanoindole (2-CI) in solution (water, 2,2,2-trifluoroethanol, acetonitrile‚ and tetrahydrofuran) was investigated by steady-state as well as time resolved fluorescence and absorption spectroscopy. The fluorescence quantum yield of 2-cyanoindole is strongly sensitive to the solvent. In water the quantum yield is as low as 4.4 × 10–4. In tetrahydrofuran, it amounts to a yield of 0.057. For 2-CI dissolved in water, a bi-exponential fluorescence decay with time constants of ∼1 ps and ∼8 ps is observed. For short wavelength excitation (266 nm) the initial fluorescence anisotropy is close to zero. For excitation with 310 nm it amounts to 0.2. In water, femtosecond transient absorption reveals that the fluorescence decay is solely due to internal conversion to the ground state. In aprotic solvents, the fluorescence decay takes much longer (acetonitrile: ∼900 ps, tetrahydrofuran: ∼2.6 ns) and intersystem crossing contributes.
Graphical abstract
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15
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Hirschi S, Ward TR, Meier WP, Müller DJ, Fotiadis D. Synthetic Biology: Bottom-Up Assembly of Molecular Systems. Chem Rev 2022; 122:16294-16328. [PMID: 36179355 DOI: 10.1021/acs.chemrev.2c00339] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The bottom-up assembly of biological and chemical components opens exciting opportunities to engineer artificial vesicular systems for applications with previously unmet requirements. The modular combination of scaffolds and functional building blocks enables the engineering of complex systems with biomimetic or new-to-nature functionalities. Inspired by the compartmentalized organization of cells and organelles, lipid or polymer vesicles are widely used as model membrane systems to investigate the translocation of solutes and the transduction of signals by membrane proteins. The bottom-up assembly and functionalization of such artificial compartments enables full control over their composition and can thus provide specifically optimized environments for synthetic biological processes. This review aims to inspire future endeavors by providing a diverse toolbox of molecular modules, engineering methodologies, and different approaches to assemble artificial vesicular systems. Important technical and practical aspects are addressed and selected applications are presented, highlighting particular achievements and limitations of the bottom-up approach. Complementing the cutting-edge technological achievements, fundamental aspects are also discussed to cater to the inherently diverse background of the target audience, which results from the interdisciplinary nature of synthetic biology. The engineering of proteins as functional modules and the use of lipids and block copolymers as scaffold modules for the assembly of functionalized vesicular systems are explored in detail. Particular emphasis is placed on ensuring the controlled assembly of these components into increasingly complex vesicular systems. Finally, all descriptions are presented in the greater context of engineering valuable synthetic biological systems for applications in biocatalysis, biosensing, bioremediation, or targeted drug delivery.
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Affiliation(s)
- Stephan Hirschi
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
| | - Thomas R Ward
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
| | - Wolfgang P Meier
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
| | - Daniel J Müller
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, 4058 Basel, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
| | - Dimitrios Fotiadis
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.,Molecular Systems Engineering, National Centre of Competence in Research (NCCR), 4002 Basel, Switzerland
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16
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Yu J, Gan L, Zhou Y, Xu J, Yun C, Fang T, Cai X. Indole‐Based Long‐Wavelength Fluorescent Probes for Bioimaging of
S
‐Nitrosylation in Mitochondria. Chemistry 2022; 28:e202201494. [DOI: 10.1002/chem.202201494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Jinfeng Yu
- School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 China
| | - Lu Gan
- School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 China
| | - Yani Zhou
- School of Basic Medical Sciences Lanzhou University Lanzhou 730000 China
| | - Jingyao Xu
- School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 China
| | - Chengyu Yun
- School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 China
| | - Tong Fang
- School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 China
| | - Xiaoqing Cai
- School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 China
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17
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Miao Q, Nitsche C, Orton H, Overhand M, Otting G, Ubbink M. Paramagnetic Chemical Probes for Studying Biological Macromolecules. Chem Rev 2022; 122:9571-9642. [PMID: 35084831 PMCID: PMC9136935 DOI: 10.1021/acs.chemrev.1c00708] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 12/11/2022]
Abstract
Paramagnetic chemical probes have been used in electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopy for more than four decades. Recent years witnessed a great increase in the variety of probes for the study of biological macromolecules (proteins, nucleic acids, and oligosaccharides). This Review aims to provide a comprehensive overview of the existing paramagnetic chemical probes, including chemical synthetic approaches, functional properties, and selected applications. Recent developments have seen, in particular, a rapid expansion of the range of lanthanoid probes with anisotropic magnetic susceptibilities for the generation of structural restraints based on residual dipolar couplings and pseudocontact shifts in solution and solid state NMR spectroscopy, mostly for protein studies. Also many new isotropic paramagnetic probes, suitable for NMR measurements of paramagnetic relaxation enhancements, as well as EPR spectroscopic studies (in particular double resonance techniques) have been developed and employed to investigate biological macromolecules. Notwithstanding the large number of reported probes, only few have found broad application and further development of probes for dedicated applications is foreseen.
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Affiliation(s)
- Qing Miao
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
- School
of Chemistry &Chemical Engineering, Shaanxi University of Science & Technology, Xi’an710021, China
| | - Christoph Nitsche
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Henry Orton
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Mark Overhand
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Gottfried Otting
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Marcellus Ubbink
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
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18
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Lu M, Toptygin D, Xiang Y, Shi Y, Schwieters CD, Lipinski EC, Ahn J, Byeon IJL, Gronenborn AM. The Magic of Linking Rings: Discovery of a Unique Photoinduced Fluorescent Protein Crosslink. J Am Chem Soc 2022; 144:10809-10816. [PMID: 35574633 PMCID: PMC9233106 DOI: 10.1021/jacs.2c02054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
Fluorosubstituted tryptophans serve
as valuable probes for fluorescence
and nuclear magnetic resonance (NMR) studies of proteins. Here, we
describe an unusual photoreactivity introduced by replacing the single
tryptophan in cyclophilin A with 7-fluoro-tryptophan. UV exposure
at 282 nm defluorinates 7-fluoro-tryptophan and crosslinks it to a
nearby phenylalanine, generating a bright fluorophore. The crosslink-containing
fluorescent protein possesses a large quantum yield of ∼0.40
with a fluorescence lifetime of 2.38 ns. The chemical nature of the
crosslink and the three-dimensional protein structure were determined
by mass spectrometry and NMR spectroscopy. To the best of our knowledge,
this is the first report of a Phe–Trp crosslink in a protein.
Our finding may break new ground for developing novel fluorescence
probes and for devising new strategies to exploit aromatic crosslinks
in proteins.
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Affiliation(s)
- Manman Lu
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
| | - Dmitri Toptygin
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Yufei Xiang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Yi Shi
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Charles D. Schwieters
- Computational Biomolecular Magnetic Resonance Core, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Emma C. Lipinski
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
| | - Jinwoo Ahn
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
| | - In-Ja L. Byeon
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
| | - Angela M. Gronenborn
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
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19
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Micikas RJ, Acharyya A, Smith AB, Gai F. Synthesis and characterization of the fluorescence utility of two Visible-Light-Absorbing tryptophan derivatives. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Wang M, Liu X, Wang L, Lu H, Gao H. Cooperative Gold/Zinc‐Catalyzed Cascade Approach to Tryptophan Derivatives from N‐arylhydroxylamines and Alkynes. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202200054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Min Wang
- Shandong University School of Chemistry and Chemical Engineering 27 South Shanda Road 250100 Ji'nan CHINA
| | - Xiao Liu
- Shandong University School of Chemistry and Chemical Engineering 27 South Shanda Road 250100 Ji'nan CHINA
| | - Liying Wang
- Shandong University School of Chemistry and Chemical Engineering 27 South Shanda Road 250100 Ji'nan CHINA
| | - Haifeng Lu
- Shandong University School of chemistry and chemical engineering CHINA
| | - Hongyin Gao
- Shandong University School of Chemistry and Chemical Engineering 27 South Shanda Road 250100 Ji'nan CHINA
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21
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Qianzhu H, Abdelkader EH, Herath ID, Otting G, Huber T. Site-Specific Incorporation of 7-Fluoro-L-tryptophan into Proteins by Genetic Encoding to Monitor Ligand Binding by 19F NMR Spectroscopy. ACS Sens 2022; 7:44-49. [PMID: 35005899 DOI: 10.1021/acssensors.1c02467] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A mutant aminoacyl-tRNA synthetase identified by a library selection system affords site-specific incorporation of 7-fluoro-L-tryptophan in response to an amber stop codon. The enzyme allows the production of proteins with a single hydrogen atom replaced by a fluorine atom as a sensitive nuclear magnetic resonance (NMR) probe. The substitution of a single hydrogen atom by another element that is as closely similar in size and hydrophobicity as possible minimizes possible perturbations in the structure, stability, and solubility of the protein. The fluorine atom enables site-selective monitoring of the protein response to ligand binding by 19F NMR spectroscopy, as demonstrated with the Zika virus NS2B-NS3 protease.
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Affiliation(s)
- Haocheng Qianzhu
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Elwy H. Abdelkader
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Iresha D. Herath
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Gottfried Otting
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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22
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Li S, Huo F, Yin C. Progress in the past five years of small organic molecule dyes for tumor microenvironment imaging. Chem Commun (Camb) 2022; 58:12642-12652. [DOI: 10.1039/d2cc04975a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The tumor microenvironment (TME) is the survival environment for tumor cell proliferation and metastasis in deep tissues.
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Affiliation(s)
- Sha Li
- Department of Chemistry, Xinzhou Teachers University, Xinzhou 034000, China
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
| | - Fangjun Huo
- Research Institute of Applied Chemistry, Shanxi University, Taiyuan 030006, China
| | - Caixia Yin
- Department of Chemistry, Xinzhou Teachers University, Xinzhou 034000, China
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
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23
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Mukherjee D, Ahmed IA, Gai F. Site-Specific Interrogation of Protein Structure and Stability. Methods Mol Biol 2022; 2376:65-87. [PMID: 34845603 DOI: 10.1007/978-1-0716-1716-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
To execute their function or activity, proteins need to possess variability in local electrostatic environment, solvent accessibility, structure, and stability. However, assessing any protein property in a site-specific manner is not easy since native spectroscopic signals often lack the needed specificity. One strategy that overcomes this limitation is to use unnatural amino acids that exhibit distinct spectroscopic features. In this chapter, we describe several such unnatural amino acids (UAAs) and their respective applications in site-specific interrogation of protein structure and stability using standard biophysical methods, including circular dichroism (CD), infrared (IR), and fluorescence spectroscopies.
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Affiliation(s)
| | - Ismail A Ahmed
- Department of Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA.
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24
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Lee S, Kim J, Koh M. Recent Advances in Fluorescence Imaging by Genetically Encoded Non-canonical Amino Acids. J Mol Biol 2021; 434:167248. [PMID: 34547330 DOI: 10.1016/j.jmb.2021.167248] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 01/09/2023]
Abstract
Technical innovations in protein labeling with a fluorophore at the specific residue have played a significant role in studying protein dynamics. The genetic code expansion (GCE) strategy enabled the precise installation of fluorophores at the tailored site of proteins in live cells with minimal perturbation of native functions. Considerable advances have been achieved over the past decades in fluorescent imaging using GCE strategies along with bioorthogonal chemistries. In this review, we discuss advances in the GCE-based strategies to site-specifically introduce fluorophore at a defined position of the protein and their bio-imaging applications.
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Affiliation(s)
- Sanghee Lee
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of HY-KIST Bio-convergence, Hanyang University, Seoul 04763, Republic of Korea
| | - Jonghoon Kim
- Department of Chemistry and Integrative Institute of Basic Science, Soongsil University, Seoul 06978, Republic of Korea
| | - Minseob Koh
- Department of Chemistry, Pusan National University, Busan 46241, Republic of Korea.
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25
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Nandy T, Singh PC. Photophysical Properties of Noncanonical Amino Acid 7-Fluorotryptophan Sharply Different from Those of Canonical Derivative Tryptophan: Spectroscopic and Quantum Chemical Calculations. J Phys Chem B 2021; 125:6214-6221. [PMID: 34081478 DOI: 10.1021/acs.jpcb.1c03319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Due to the limited number of naturally existing canonical amino acids, several noncanonical amino acids have been designed to understand the diverse complex biological functions. Fluorinated amino acids are one of the important noncanonical amino acids that have been used to understand the different complex processes of proteins. In this study, the photophysical properties of the noncanonical amino acid 7-fluorotryptophan (7F-Trp) in different solvents have been investigated using extensive spectroscopic as well as quantum chemical calculation methods and compared with those of tryptophan (Trp). The spectroscopic and quantum chemical calculation data suggest that unlike Trp, 7F-Trp can be used to detect the excited-state proton transfer from solvents depending on its acidity, which makes 7F-Trp a potential candidate for sensing the excited-state proton transfer from the solvent molecules.
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Affiliation(s)
- Tonima Nandy
- School of Chemical Sciences, Indian Association for the Cultivation of Sciences, Kolkata 700032, India
| | - Prashant Chandra Singh
- School of Chemical Sciences, Indian Association for the Cultivation of Sciences, Kolkata 700032, India
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26
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Fong KP, Ahmed IA, Mravic M, Jo H, Kim OV, Litvinov RI, Weisel JW, DeGrado WF, Gai F, Bennett JS. Visualization of Platelet Integrins via Two-Photon Microscopy Using Anti-transmembrane Domain Peptides Containing a Blue Fluorescent Amino Acid. Biochemistry 2021; 60:1722-1730. [PMID: 34010565 DOI: 10.1021/acs.biochem.1c00238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fluorescent reporters commonly used to visualize proteins can perturb both protein structure and function. Recently, we found that 4-cyanotryptophan (4CN-Trp), a blue fluorescent amino acid, is suitable for one-photon imaging applications. Here, we demonstrate its utility in two-photon fluorescence microscopy by using it to image integrins on cell surfaces. Specifically, we used solid-phase peptide synthesis to generate CHAMP peptides labeled with 4-cyanoindole (4CNI) at their N-termini to image integrins on cell surfaces. CHAMP (computed helical anti-membrane protein) peptides spontaneously insert into membrane bilayers to target integrin transmembrane domains and cause integrin activation. We found that 4CNI labeling did not perturb the ability of CHAMP peptides to insert into membranes, bind to integrins, or cause integrin activation. We then used two-photon fluorescence microscopy to image 4CNI-containing integrins on the surface of platelets. Compared to a 4CNI-labeled scrambled peptide that uniformly decorated cell surfaces, 4CNI-labeled CHAMP peptides were present in discrete blue foci. To confirm that these foci represented CN peptide-containing integrins, we co-stained platelets with integrin-specific fluorescent monoclonal antibodies and found that CN peptide and antibody fluorescence coincided. Because 4CNI can readily be biosynthetically incorporated into proteins with little if any effect on protein structure and function, it provides a facile way to directly monitor protein behavior and protein-protein interactions in cellular environments. In addition, these results clearly demonstrate that the two-photon excitation cross section of 4CN-Trp is sufficiently large to make it a useful two-photon fluorescence reporter for biological applications.
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Affiliation(s)
- Karen P Fong
- Hematology-Oncology Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Ismail A Ahmed
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Marco Mravic
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158-2517, United States
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158-2517, United States
| | - Oleg V Kim
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Rustem I Litvinov
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - John W Weisel
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158-2517, United States
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Joel S Bennett
- Hematology-Oncology Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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27
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Henrichs C, Zimmermann S, Hebestreit ML, Schmitt M. Excited state structure of isolated 2-cyanoindole and the binary 2-cyanoindole-(H2O)1 cluster from a combined Franck-Condon and rotational constants fit. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Acharyya A, Zhang W, Gai F. Tryptophan as a Template for Development of Visible Fluorescent Amino Acids. J Phys Chem B 2021; 125:5458-5465. [PMID: 34029101 DOI: 10.1021/acs.jpcb.1c02321] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Most biological systems, at both molecular and cellular levels, are intrinsically complex, diverse, and nonfluorescent. Therefore, studying their structures, dynamics, and interactions via fluorescence-based methods requires incorporation of one or multiple external fluorophores that would not significantly affect any native property of the system in question. This requirement necessitates the development of a diverse set of fluorescence reporters that differ in chemical, physical, and photophysical properties. Herein, we offer our perspective on the need for, recent progress in, and future directions of developing tryptophan-based fluorescent amino acids.
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Affiliation(s)
- Arusha Acharyya
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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29
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Pagar AD, Patil MD, Flood DT, Yoo TH, Dawson PE, Yun H. Recent Advances in Biocatalysis with Chemical Modification and Expanded Amino Acid Alphabet. Chem Rev 2021; 121:6173-6245. [PMID: 33886302 DOI: 10.1021/acs.chemrev.0c01201] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The two main strategies for enzyme engineering, directed evolution and rational design, have found widespread applications in improving the intrinsic activities of proteins. Although numerous advances have been achieved using these ground-breaking methods, the limited chemical diversity of the biopolymers, restricted to the 20 canonical amino acids, hampers creation of novel enzymes that Nature has never made thus far. To address this, much research has been devoted to expanding the protein sequence space via chemical modifications and/or incorporation of noncanonical amino acids (ncAAs). This review provides a balanced discussion and critical evaluation of the applications, recent advances, and technical breakthroughs in biocatalysis for three approaches: (i) chemical modification of cAAs, (ii) incorporation of ncAAs, and (iii) chemical modification of incorporated ncAAs. Furthermore, the applications of these approaches and the result on the functional properties and mechanistic study of the enzymes are extensively reviewed. We also discuss the design of artificial enzymes and directed evolution strategies for enzymes with ncAAs incorporated. Finally, we discuss the current challenges and future perspectives for biocatalysis using the expanded amino acid alphabet.
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Affiliation(s)
- Amol D Pagar
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea
| | - Mahesh D Patil
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea
| | - Dillon T Flood
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Tae Hyeon Yoo
- Department of Molecular Science and Technology, Ajou University, 206 World cup-ro, Yeongtong-gu, Suwon 16499, Korea
| | - Philip E Dawson
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Hyungdon Yun
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea
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30
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Hebestreit ML, Lartian H, Henrichs C, Kühnemuth R, Meerts WL, Schmitt M. Excited state dipole moments and lifetimes of 2-cyanoindole from rotationally resolved electronic Stark spectroscopy. Phys Chem Chem Phys 2021; 23:10196-10204. [PMID: 33951126 DOI: 10.1039/d1cp00097g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The permanent dipole moments of 2-cyanoindole (cyanoindole = CNI) in its ground and lowest excited singlet states have been determined from rotationally resolved electronic Stark spectroscopy under jet-cooled conditions. From the orientation of the transition dipole moment and the geometry changes upon electronic excitation the lowest excited singlet state could be shown to be of Lb-symmetry. The general statement, that the La-state has the larger permanent dipole moment of the two lowest excited singlet states, will be challenged in this contribution. On the basis of the different electronic nature of the first excited singlet state the behavior of 2-, 3-, 4- and 5-CNI is discussed. The excited state lifetime of isolated 2-CNI in the gas phase has been determined to be 9.4 ns. This value is compared to the excited state lifetime in ethyl acetate solution of 2.6 ns, which was quantified with a Strickler-Berg analysis. Using water as solvent shortens the 2-CNI lifetime to <40 ps. The reason for this drastic shortening is discussed in detail. Additionally, the rotationally resolved electronic spectrum of 2-CNI(1-d1) has been measured and analyzed.
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Affiliation(s)
- Marie-Luise Hebestreit
- Heinrich-Heine-Universität, Institut für Physikalische Chemie I, D-40225 Düsseldorf, Germany.
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31
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Micikas RJ, Ahmed IA, Acharyya A, Smith AB, Gai F. Tuning the electronic transition energy of indole via substitution: application to identify tryptophan-based chromophores that absorb and emit visible light. Phys Chem Chem Phys 2021; 23:6433-6437. [PMID: 33710175 DOI: 10.1039/d0cp06710e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Fluorescent amino acids (FAAs) offer significant advantages over fluorescent proteins in applications where the fluorophore size needs to be limited or minimized. A long-sought goal in biological spectroscopy/microcopy is to develop visible FAAs by modifying the indole ring of tryptophan. Herein, we examine the absorption spectra of a library of 4-substituted indoles and find that the frequency of the absorption maximum correlates linearly with the global electrophilicity index of the substituent. This finding permits us to identify two promising candidates, 4-formyltryptophan (4CHO-Trp) and 4-nitrotryptophan (4NO2-Trp), both of which can be excited by visible light. Further fluorescence measurements indicate that while 4CHO-indole (and 4CHO-Trp) emits cyan fluorescence with a reasonably large quantum yield (ca. 0.22 in ethanol), 4NO2-indole is essentially non-fluorescent, suggesting that 4CHO-Trp (4NO2-Trp) could be useful as a fluorescence reporter (quencher). In addition, we present a simple method for synthesizing 4CHO-Trp.
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Affiliation(s)
- Robert J Micikas
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.
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32
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Excited state structure of isolated 4-cyanoindole from a combined Franck-Condon and rotational constants analysis†. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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33
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Boaro A, Ageitos L, Torres M, Bartoloni FH, de la Fuente-Nunez C. Light-Emitting Probes for Labeling Peptides. CELL REPORTS. PHYSICAL SCIENCE 2020; 1:100257. [PMID: 34396352 PMCID: PMC8360326 DOI: 10.1016/j.xcrp.2020.100257] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Peptides are versatile biopolymers composed of 2-100 amino acid residues that present a wide range of biological functions and constitute potential therapies for numerous diseases, partly due to their ability to penetrate cell membranes. However, their mechanisms of action have not been fully elucidated due to the lack of appropriate tools. Existing light-emitting probes are limited by their cytotoxicity and large size, which can alter peptide structure and function. Here, we describe the available fluorescent, bioluminescent, and chemiluminescent probes for labeling peptides, with a focus on minimalistic options.
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Affiliation(s)
- Andreia Boaro
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, and Department of Bioengineering, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA 19104, USA
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Avenida dos Estados, 5001, Santo André, São Paulo 09210-580, Brazil
| | - Lucía Ageitos
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, and Department of Bioengineering, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA 19104, USA
- Centro de Investigacións Científicas Avanzadas (CICA) e Departamento de Química, Facultade de Ciencias, Universidade da Coruña, Calle de la Maestranza, 9, A Coruña 15071, Spain
| | - Marcelo Torres
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, and Department of Bioengineering, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA 19104, USA
| | - Fernando Heering Bartoloni
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Avenida dos Estados, 5001, Santo André, São Paulo 09210-580, Brazil
| | - Cesar de la Fuente-Nunez
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, and Department of Bioengineering, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA 19104, USA
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34
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Liu J, Liu X, Zhang F, Qu J, Sun H, Zhu Q. A Peptide Stapling Strategy with Built‐In Fluorescence by Direct Late‐Stage C(sp
2
)−H Olefination of Tryptophan. Chemistry 2020; 26:16122-16128. [DOI: 10.1002/chem.202003548] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/27/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Jiang Liu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province College of Biotechnology and Bioengineering Zhejiang University of Technology Hangzhou 310014 P.R. China
| | - Xin Liu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province College of Biotechnology and Bioengineering Zhejiang University of Technology Hangzhou 310014 P.R. China
| | - Fangfang Zhang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province College of Biotechnology and Bioengineering Zhejiang University of Technology Hangzhou 310014 P.R. China
| | - Jiaojiao Qu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province College of Biotechnology and Bioengineering Zhejiang University of Technology Hangzhou 310014 P.R. China
| | - Hongyan Sun
- Department of Chemistry and Center of Super-Diamond and Advanced Films (COSDAF) City University of Hong Kong Hong Kong P.R. China
| | - Qing Zhu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province College of Biotechnology and Bioengineering Zhejiang University of Technology Hangzhou 310014 P.R. China
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Gleason PR, Kelly PI, Grisingher DW, Mills JH. An intrinsic FRET sensor of protein-ligand interactions. Org Biomol Chem 2020; 18:4079-4084. [PMID: 32427252 PMCID: PMC7313717 DOI: 10.1039/d0ob00793e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe an approach for the development of fluorescent sensors of metabolite binding in which a genetically encoded fluorescent non-canonical amino acid (fNCAA) containing a 7-hydroxycoumarin moiety (7-HCAA) forms a FRET pair with native tryptophan residues. Although previous studies demonstrated the potential for using 7-HCAA as an acceptor for tryptophan, this approach has not yet been explored within a single protein containing multiple tryptophan residues. A structure-based analysis of a hexokinase enzyme with multiple native tryptophan residues identified glutamate 50 as a potential site of 7-HCAA incorporation; Glu50 moves closer to the native tryptophans upon substrate binding. Substitution of 7-HCAA at residue 50 led to an increase in FRET efficiency in the presence of the substrate; this effect was not observed in a control protein where no change in distance between 7-HCAA and the native tryptophans occurs on substrate binding. This system was then used to directly observe differences in binding affinity of the hexokinase that occur at a number of pH values. Our approach builds on previous research in that it eliminates the need for the incorporation of multiple fNCAAs or fluorescent labels within a target protein and can be used to study substrate binding with native ligands. As such, it serves to expand the versatility of FRET-based techniques.
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Affiliation(s)
- Patrick R Gleason
- School of Molecular Sciences and The Biodesign Center for Molecular Design and Biomimetics, Arizona State University, Tempe, AZ 85287, USA.
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36
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Fluorescent amino acids as versatile building blocks for chemical biology. Nat Rev Chem 2020; 4:275-290. [PMID: 37127957 DOI: 10.1038/s41570-020-0186-z] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2020] [Indexed: 12/13/2022]
Abstract
Fluorophores have transformed the way we study biological systems, enabling non-invasive studies in cells and intact organisms, which increase our understanding of complex processes at the molecular level. Fluorescent amino acids have become an essential chemical tool because they can be used to construct fluorescent macromolecules, such as peptides and proteins, without disrupting their native biomolecular properties. Fluorescent and fluorogenic amino acids with unique photophysical properties have been designed for tracking protein-protein interactions in situ or imaging nanoscopic events in real time with high spatial resolution. In this Review, we discuss advances in the design and synthesis of fluorescent amino acids and how they have contributed to the field of chemical biology in the past 10 years. Important areas of research that we review include novel methodologies to synthesize building blocks with tunable spectral properties, their integration into peptide and protein scaffolds using site-specific genetic encoding and bioorthogonal approaches, and their application to design novel artificial proteins, as well as to investigate biological processes in cells by means of optical imaging.
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37
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Pang X, Li Y, Zhou Z, Lu Q, Xie R, Wu C, Zhang Y, Li H. Visualization of endogenous β-galactosidase activity in living cells and zebrafish with a turn-on near-infrared fluorescent probe. Talanta 2020; 217:121098. [PMID: 32498839 DOI: 10.1016/j.talanta.2020.121098] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/23/2020] [Accepted: 04/27/2020] [Indexed: 01/29/2023]
Abstract
β-Galactosidase (β-gal) is an important biomarker for primary ovarian cancers. Developing noninvasive bioimaging probes for studying the activity of β-gal is highly desirable for cancer diagnosis. Herein, a turn-on near-infrared (NIR) fluorescent probe, 2-((6-(((2S, 3R, 4S, 5R, 6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran -2-yl)oxy)-2,3-dihydro-1H-xanthen-4-yl)methylene)malononitrile named DXM-βgal, was rationally designed based on enzymatic reaction for the detection of β-gal activity both in vitro and in vivo. Upon incubating with β-gal, DXM-βgal displayed a significant fluorescence enhancement at 640 nm, accompanying by a color change of solution color from red to purple. DXM-βgal exhibited high selectivity and sensitively to β-gal with low limit of detection (2.92 × 10-4 U mL-1). Besides, based on its advantages of long-wavelength emission and excellent biocompatibility, DXM-βgal was successfully applied to imaging β-gal in living cells and zebrafish. Given these prominent properties, we believe that DXM-βgal will be a potential tool for investigating β-gal activity in biomedical research.
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Affiliation(s)
- Xiao Pang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China
| | - Yaqian Li
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China
| | - Zile Zhou
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China
| | - Qiujun Lu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China
| | - Ruihua Xie
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China
| | - Cuiyan Wu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China.
| | - Youyu Zhang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China
| | - Haitao Li
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, PR China.
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Abstract
Most biological molecules are intrinsically non- or weakly-fluorescent, hence requiring labeling with an external fluorophore(s) to be studied via fluorescence-based techniques. However, such labeling could perturb the native property of the system in question. One effective strategy to minimize such undesirable perturbation is to use fluorophores that are simple analogs of natural amino acids. In this chapter, we describe the synthesis and spectroscopic utility of two indole-based fluorophores, 4-cynaotryprophan (4CN-Trp) and 4-cyanoindole-2'-deoxyribonucleoside (4CNI-NS), with a focus on 4CN-Trp. This unnatural amino acid, which is only slightly larger than its natural counterpart, tryptophan (Trp), exhibits unique photophysical properties, making it a versatile fluorophore in biological spectroscopic and imaging applications. Through several specific examples, we highlight its broad utility in the study of various biological problems and processes.
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39
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Inada H, Furukawa K, Shibuya M, Yamamoto Y. One-pot, two-step synthesis of unnatural α-amino acids involving the exhaustive aerobic oxidation of 1,2-diols. Chem Commun (Camb) 2019; 55:15105-15108. [PMID: 31782427 DOI: 10.1039/c9cc07889d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Herein, we report the nor-AZADO-catalyzed exhaustive aerobic oxidations of 1,2-diols to α-keto acids. Combining oxidation with transamination using dl-2-phenylglycine led to the synthesis of free α-amino acids (AAs) in one pot. This method enables the rapid and flexible preparation of a variety of valuable unnatural AAs, such as fluorescent AAs, photoactivatable AAs, and other functional AAs for bioorthogonal reactions.
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Affiliation(s)
- Haruki Inada
- Department of Basic Medicinal Sciences Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
| | - Keisuke Furukawa
- Department of Basic Medicinal Sciences Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
| | - Masatoshi Shibuya
- Department of Basic Medicinal Sciences Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
| | - Yoshihiko Yamamoto
- Department of Basic Medicinal Sciences Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
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40
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You M, Fan H, Wang Y, Zhang W. Aldehyde-derivatized indoles as fluorescent probes for hydration environments. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.110438] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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41
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Abou-Hatab S, Matsika S. Theoretical Investigation of Positional Substitution and Solvent Effects on n-Cyanoindole Fluorescent Probes. J Phys Chem B 2019; 123:7424-7435. [DOI: 10.1021/acs.jpcb.9b05961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Salsabil Abou-Hatab
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Spiridoula Matsika
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
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42
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Zhang K, Ahmed IA, Kratochvil HT, DeGrado WF, Gai F, Jo H. Synthesis and application of the blue fluorescent amino acid l-4-cyanotryptophan to assess peptide-membrane interactions. Chem Commun (Camb) 2019; 55:5095-5098. [PMID: 30957824 PMCID: PMC6508085 DOI: 10.1039/c9cc01152h] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Recently, l-4-cyanotryptophan has been shown to be an efficient blue fluorescence emitter, with the potential to enable novel applications in biological spectroscopy and microscopy. However, lack of facile synthetic routes to this unnatural amino acid limits its wide use. Herein, we describe an expedient approach to synthesize Fmoc protected l-4-cyanotryptophan with high optical purity (>99%). Additionally, we test the utility of this blue fluorophore in imaging cell-membrane-bound peptides and in determining peptide-membrane binding constants.
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Affiliation(s)
- Kui Zhang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, United States
| | - Ismail A. Ahmed
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Huong T. Kratochvil
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, United States
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, United States
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, United States
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43
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Studies on the Interaction between Poly-Phosphane Gold(I) Complexes and Dihydrofolate Reductase: An Interplay with Nicotinamide Adenine Dinucleotide Cofactor. Int J Mol Sci 2019; 20:ijms20071802. [PMID: 30979096 PMCID: PMC6479694 DOI: 10.3390/ijms20071802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 01/06/2023] Open
Abstract
A class of gold(I) phosphane complexes have been identified as inhibitors of dihydrofolate reductase (DHFR) from E. coli, an enzyme that catalyzes the reduction of dihydrofolate (DHF) to tetrahydrofolate (THF), using NADPH as a coenzyme. In this work, to comprehend the nature of the interaction at the basis of these inhibitory effects, the binding properties of bis- and tris-phosphane gold(I) chloride compounds in regards to DHFR have been studied by emission spectroscopy and spectrophotometric assays. The lack of cysteine and seleno-cysteine residues in the enzyme active site, the most favorable sites of attack of Au(I) moieties, makes this work noteworthy. The interaction with the gold compounds results into the quenching of the DHFR tryptophan's emissions and in an enhancement of their intrinsic emission intensities. Moreover, a modulating action of NADPH is highlighted by means of an increase of the gold compound affinity toward the enzyme; in fact, the dissociation constants calculated for the interactions between DHFR and each gold compound in the presence of saturating NADPH were lower than the ones observed for the apo-enzyme. The fluorimetric data afforded to Kd values ranged from 2.22 ± 0.25 µM for (PPh₃)₂AuCl in the presence of NADPH to 21.4 ± 3.85 µM for ⁴L₃AuTf in the absence of NADPH. By elucidating the energetic aspects of the binding events, we have attempted to dissect the role played by the gold phosphane/protein interactions in the inhibitory activity, resulting in an exothermic enthalpy change and a positive entropic contribution (ΔH° = -5.04 ± 0.08 kcal/mol and ΔS° = 7.34 ± 0.005 cal/mol·K).
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44
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You M, Zhou L, Huang X, Wang Y, Zhang W. Isonitrile-Derivatized Indole as an Infrared Probe for Hydrogen-Bonding Environments. Molecules 2019; 24:molecules24071379. [PMID: 30965674 PMCID: PMC6480494 DOI: 10.3390/molecules24071379] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/24/2019] [Accepted: 03/30/2019] [Indexed: 11/18/2022] Open
Abstract
The isonitrile (NC) group has been shown to be a promising infrared probe for studying the structure and dynamics of biomolecules. However, there have been no systematic studies performed on the NC group as an infrared probe, when it is bonded to an indole ring. Here, we systematically study the NC stretching mode of two model compounds, 5-isocyano-1H-indole (5ICI) and 5-isocyano-1-methyl-1H-indole (NM5ICI), using Fourier transform infrared (FTIR) spectroscopy. The NC stretching frequency is shown to be strongly dependent on the polarizability of protic solvents and the density of hydrogen-bond donor groups in the solvent when NC is bonded to an indole ring. Infrared pump–probe studies of 5ICI in DMSO and in EtOH further support that the NC stretching mode could be used as a site-specific infrared probe for local environments when NC is bonded to an indole ring.
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Affiliation(s)
- Min You
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China.
| | - Liang Zhou
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China.
| | - Xinyue Huang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China.
| | - Yang Wang
- Department of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China.
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45
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Richardson SL, Dods KK, Abrigo NA, Iqbal ES, Hartman MC. In vitro genetic code reprogramming and expansion to study protein function and discover macrocyclic peptide ligands. Curr Opin Chem Biol 2018; 46:172-179. [PMID: 30077877 DOI: 10.1016/j.cbpa.2018.07.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 05/02/2018] [Accepted: 07/13/2018] [Indexed: 01/26/2023]
Abstract
The ability to introduce non-canonical amino acids into peptides and proteins is facilitated by working within in vitro translation systems. Non-canonical amino acids can be introduced into these systems using sense codon reprogramming, stop codon suppression, and by breaking codon degeneracy. Here, we review how these techniques have been used to create proteins with novel properties and how they facilitate sophisticated studies of protein function. We also discuss how researchers are using in vitro translation experiments with non-canonical amino acids to explore the tolerance of the translation apparatus to artificial building blocks. Finally, we give several examples of how non-canonical amino acids can be combined with mRNA-displayed peptide libraries for the creation of protease-stable, macrocyclic peptide libraries for ligand discovery.
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Affiliation(s)
- Stacie L Richardson
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, USA; Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, USA
| | - Kara K Dods
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, USA; Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, USA
| | - Nicolas A Abrigo
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, USA; Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, USA
| | - Emil S Iqbal
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, USA; Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, USA
| | - Matthew Ct Hartman
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, USA; Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, USA.
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46
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Huang XY, You M, Ran GL, Fan HR, Zhang WK. Ester-Derivatized indoles as fluorescent and infrared probes for hydration environments. CHINESE J CHEM PHYS 2018. [DOI: 10.1063/1674-0068/31/cjcp1805118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Xin-yue Huang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
| | - Min You
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
| | - Guang-liu Ran
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
| | - Hao-ran Fan
- Department of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wen-kai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
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47
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Passow KT, Harki DA. 4-Cyanoindole-2'-deoxyribonucleoside (4CIN): A Universal Fluorescent Nucleoside Analogue. Org Lett 2018; 20:4310-4313. [PMID: 29989830 PMCID: PMC6168291 DOI: 10.1021/acs.orglett.8b01746] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The synthesis and characterization of a universal and fluorescent nucleoside, 4-cyanoindole-2'-deoxyribonucleoside (4CIN), and its incorporation into DNA is described. 4CIN is a highly efficient fluorophore with quantum yields >0.90 in water. When incorporated into duplex DNA, 4CIN pairs equivalently with native nucleobases and has uniquely high quantum yields ranging from 0.15 to 0.31 depending on sequence and hybridization contexts, surpassing that of 2-aminopurine, the prototypical nucleoside fluorophore. 4CIN constitutes a new isomorphic nucleoside for diverse applications.
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Affiliation(s)
- Kellan T. Passow
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
| | - Daniel A. Harki
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455
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48
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Martin JP, Fetto NR, Tucker MJ. Comparison of biological chromophores: photophysical properties of cyanophenylalanine derivatives. Phys Chem Chem Phys 2018; 18:20750-7. [PMID: 27412819 DOI: 10.1039/c6cp04154j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Within this work, the family of cyanophenylalanine spectroscopic reporters is extended by showing the ortho and meta derivatives have intrinsic photophysical properties that are useful for studies of protein structure and dynamics. The molar absorptivities of 2-cyanophenylalanine and 3-cyanophenylalanine are shown to be comparable to that of 4-cyanophenylalanine with similar spectral features in their absorbance and emission profiles, demonstrating that these probes can be utilized interchangeably. The fluorescence quantum yields are also on the same scale as commonly used fluorophores in peptides and proteins, tyrosine and tryptophan. These new cyano-fluorophores can be paired with either 4-cyanophenylalanine or tryptophan to capture distances in peptide structure through Förster resonance energy transfer. Additionally, the spectroscopic properties of these chromophores can report the local solvent environment via changes in fluorescence emission intensity as a result of hydrogen bonding and/or hydration. A decrease in the quantum yield is also observed in basic environments due to photoinduced electron transfer from a deprotonated amine in the free PheCN species and at the N-terminus of a short peptide, providing an avenue to detect pH in biological systems. Our results show the potential of these probes, 2-cyanophenylalanine and 3-cyanophenylalanine, to be incorporated into a single peptide chain, either individually or in tandem with 4-cyanophenylalanine, tryptophan, or tyrosine, in order to obtain information about peptide structure and dynamics.
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Affiliation(s)
- Joshua P Martin
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
| | - Natalie R Fetto
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
| | - Matthew J Tucker
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
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Ranganathan R, Lenti G, Tassone NM, Scannell BJ, Southern CA, Karver CE. Design and application of a fluorogenic assay for monitoring inflammatory caspase activity. Anal Biochem 2018; 543:1-7. [DOI: 10.1016/j.ab.2017.11.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/10/2017] [Accepted: 11/29/2017] [Indexed: 12/22/2022]
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Mukherjee D, Ortiz Rodriguez LI, Hilaire MR, Troxler T, Gai F. 7-Cyanoindole fluorescence as a local hydration reporter: application to probe the microheterogeneity of nine water-organic binary mixtures. Phys Chem Chem Phys 2018; 20:2527-2535. [PMID: 29313858 DOI: 10.1039/c7cp07160d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Considerable efforts have been devoted to the development of spectroscopic probes that are sensitive to water and can be used to monitor, for example, biological and chemical processes involving dehydration or hydration. Continuing this line of research, herein we show that 7-cyanoindole can serve as a sensitive fluorescence probe of hydration as its fluorescence properties, including intensity, peak wavelength and lifetime, depend on the amount of water in nine water-organic solvent mixtures. Our results indicate that 7-cyanoindole is not only able to reveal the underlying microheterogeneity of these binary solvent systems, but also offers distinct advantages. These include: (1) its fluorescence intensity increases more than ten times upon going from a hydrated to a dehydrated environment; (2) its peak wavelength shifts as much as 35 nm upon dehydration; (3) its single-exponential fluorescence decay lifetime increases from 2.0 ns in water to 8-16 ns in water-organic binary mixtures, making it viable to distinguish between differently hydrated environments via fluorescence lifetime measurements; and (4) its absorption spectrum is significantly red-shifted from that of indole, making selective excitation of its fluorescence possible in the presence of naturally occurring amino-acid fluorophores. Moreover, we find that for seven binary mixtures the fluorescence lifetimes of 7-cyanoindole measured at solvent compositions where maximum microheterogeneity occurs correlate linearly with the peak wavenumbers of its fluorescence spectra obtained in the respective pure organic solvents. This suggests that the microheterogeneities of these binary mixtures bear certain similarity, a phenomenon that warrants further investigation.
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Affiliation(s)
- Debopreeti Mukherjee
- Department of Chemistry University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.
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