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Luan J, Li Y, Yuan J, Wang Z, Shang X, Wang KP, Fang Y, Chen S, Hu ZQ. Simple cyclic chalcone dye with multiple optical functions: Piezochromism and lysosomes staining. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 318:124485. [PMID: 38788510 DOI: 10.1016/j.saa.2024.124485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/16/2024] [Accepted: 05/19/2024] [Indexed: 05/26/2024]
Abstract
Both artificially synthesized and naturally occurring cyclic chalcones have been widely studied for their excellent biological activities. However, research on its photophysical properties is still limited. In the present study, we designed and synthesized a small molecule fluorescent dye based on the ICT effect, using dimethylamino as the electron-donating group and carbonyl as the electron withdrawing group, and investigated its photophysical properties in depth. Although YB is a simple small molecule, it exhibits significant piezochromic properties. The fluorescence of YB can change from green to yellow through grinding. After solvent fumigation, the fluorescence reverts to green. Furthermore, YB was used successfully in the lysosomal targeting. This study expands the research on the photophysical properties of cyclic chalcone and give richness to application of cyclic chalcone compounds.
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Affiliation(s)
- Junyu Luan
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Yahang Li
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Jianhao Yuan
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Zezhong Wang
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Xianzhao Shang
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Kun-Peng Wang
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Ying Fang
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
| | - Shaojin Chen
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
| | - Zhi-Qiang Hu
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
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Chawla M, Poater A, Oliva R, Cavallo L. Unveiling structural and energetic characterization of the emissive RNA alphabet anchored in the methylthieno[3,4- d]pyrimidine heterocycle core. Phys Chem Chem Phys 2024; 26:16358-16368. [PMID: 38805177 DOI: 10.1039/d3cp06136a] [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: 05/29/2024]
Abstract
This study presents a comprehensive theoretical exploration of the fluorescent non-natural emissive nucleobases- mthA, mthG, mthC, and mthU derived from the methylthieno[3,4-d]pyrimidine heterocycle. Our calculations, aligning with experimental findings, reveal that these non-natural bases exert minimal influence on the geometry of classical Watson-Crick base pairs within an RNA duplex, maintaining H-bonding akin to natural bases. In terms of energy, the impact of the modified bases, but for mthG, is also found to be little significant. We delved into an in-depth analysis of the photophysical properties of these non-natural bases. This investigation unveiled a correlation between their absorption/emission peaks and the substantial impact of the modification on the energy levels of the highest unoccupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbital (LUMO). Notably, this alteration in energy levels resulted in a significant reduction of the HOMO-LUMO gap, from approximately 5.4-5.5 eV in the natural bases, to roughly 3.9-4.7 eV in the modified bases. This shift led to a consequential change in absorption and emission spectra towards longer wavelengths, elucidating their bathochromic shift.
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Affiliation(s)
- Mohit Chawla
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, KAUST Catalysis Center, Thuwal 23955-6900, Saudi Arabia.
| | - Albert Poater
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, c/Ma Aurèlia Capmany 69, Girona 17003, Catalonia, Spain
| | - Romina Oliva
- Department of Sciences and Technologies, University Parthenope of Naples, Centro Direzionale Isola C4, Naples, I-80143, Italy
| | - Luigi Cavallo
- King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, KAUST Catalysis Center, Thuwal 23955-6900, Saudi Arabia.
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Johnson RE, Murray MT, Roby DJ, Bycraft LJ, Churcher ZR, Yadav S, Johnson PE, Wetmore SD, Manderville RA. Unlocking Pb 2+ Sensing Potential in a DNA G-Quadruplex via Loop Modification with Fluorescent Chalcone Surrogates. ACS Sens 2023; 8:4756-4764. [PMID: 38063049 DOI: 10.1021/acssensors.3c01866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The ability of guanine (G)-rich DNA to bind toxic lead (Pb2+) ions within a G-quadruplex (GQ) motif is a leading DNA biosensor strategy. A major analytical hurdle for GQ detection of Pb2+ is competitive GQ templating by potassium (K+) ions. We employ the on-strand DNA synthesis of internal fluorescent chalcone surrogates within the 15-mer thrombin binding aptamer (TBA15) to address this challenge. Replacement of thymidine at the 3-position (T3) within TBA15 with an indole-4-hydroxy-indanone (Ind4HI) chalcone strongly decreases K+-GQ stability while enhancing Pb2+-GQ stability to increase Pb2+ binding specificity. The new T3-Ind4HI probe exhibits a 15-fold increase in fluorescence intensity upon binding of Pb2+ by the modified TBA15 and can detect 6.4 nM Pb2+ in the presence of 10 mM K+. Thus, replacement of the T3 residue of TBA15 with the new Ind4HI probe modulates metal ion affinity by native TBA15 to solve the analytical challenge posed by K+ in real water samples for detecting Pb2+ to meet regulatory guidelines by using a GQ biosensor.
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Affiliation(s)
- Ryan E Johnson
- Departments of Chemistry and Toxicology, University of Guelph, Guelph N1G 2W1, Ontario, Canada
| | - Makay T Murray
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge T1K 3M4, Alberta, Canada
| | - Dylan J Roby
- Departments of Chemistry and Toxicology, University of Guelph, Guelph N1G 2W1, Ontario, Canada
| | - Lucas J Bycraft
- Departments of Chemistry and Toxicology, University of Guelph, Guelph N1G 2W1, Ontario, Canada
| | - Zachary R Churcher
- Department of Chemistry, York University, Toronto M3J 1P3, Ontario, Canada
| | - Saanya Yadav
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge T1K 3M4, Alberta, Canada
| | - Philip E Johnson
- Department of Chemistry, York University, Toronto M3J 1P3, Ontario, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge T1K 3M4, Alberta, Canada
| | - Richard A Manderville
- Departments of Chemistry and Toxicology, University of Guelph, Guelph N1G 2W1, Ontario, Canada
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Johnson RE, Murray MT, Bycraft LJ, Myler P, Wetmore SD, Manderville RA. Harnessing a 4-Formyl-Aniline Handle to Tune the Stability of a DNA Aptamer-Protein Complex via Fluorescent Surrogates. Bioconjug Chem 2023; 34:2066-2076. [PMID: 37857354 DOI: 10.1021/acs.bioconjchem.3c00373] [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: 10/21/2023]
Abstract
Interactions between DNA aptamers and protein targets hold promise for the development of pharmaceuticals and diagnostics. As such, the utilization of fluorescent nucleobase surrogates in studying aptamer-protein interactions is a powerful tool due to their ability to provide site-specific information through turn-on fluorescence. Unfortunately, previously described turn-on probes serving as nucleobase replacements have only been strongly disruptive to the affinity of aptamer-protein interactions. Herein, we present a modified TBA15 aptamer for thrombin containing a fluorescent surrogate that provides site-specific turn-on emission with low nanomolar affinity. The modification, referred to as AnBtz, was substituted at position T3 and provided strong turn-on emission (Irel ≈ 4) and brightness (ε·Φ > 20 000 cm-1 M-1) with an apparent dissociation constant (Kd) of 15 nM to afford a limit of detection (LOD) of 10 nM for thrombin in 20% human serum. The probe was selected through a modular "on-strand" synthesis process that utilized a 4-formyl-aniline (4FA) handle. Using this platform, we were able to enhance the affinity of the final aptamer conjugate by ∼30-fold in comparison with the initial conjugate design. Molecular dynamics simulations provide insight into the structural basis for this phenomenon and highlight the importance of targeting hydrophobic protein binding sites with fluorescent nucleobase surrogates to create new contacts with protein targets.
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Affiliation(s)
- Ryan E Johnson
- Departments of Chemistry & Toxicology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Makay T Murray
- Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Lucas J Bycraft
- Departments of Chemistry & Toxicology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Peter Myler
- Departments of Chemistry & Toxicology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Stacey D Wetmore
- Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Richard A Manderville
- Departments of Chemistry & Toxicology, University of Guelph, Guelph, ON N1G 2W1, Canada
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Regan KT, Pounder A, Lin C, Chen LD, Manderville RA. Isomer-Specific Solvatochromic and Molecular Rotor Properties of ESIPT-Active Push-Pull Fluorescent Chalcone Dyes. J Phys Chem A 2023; 127:8365-8373. [PMID: 37773491 DOI: 10.1021/acs.jpca.3c04903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2023]
Abstract
Aromatic chromophores possessing intramolecular hydrogen-bonds that can undergo excited-state intramolecular proton transfer (ESIPT) are critical tools for chemosensing/biosensing applications because they create large Stokes-shifted fluorescence with no overlap with the absorption spectrum to limit back-ground interferences. Classic ESIPT-active fluorophores, such as the 2-(2'-hydroxyphenyl) benzazole (HBX) series (X = NH, O, S), favor a ground-state (GS) enol (E) form that undergoes ESIPT to afford an excited-state (ES) keto (K) tautomer that generates red-shifted fluorescence. Herein, we have attached the HBX moiety to 6-methoxy-indanone (6MI) to create isomeric (ortho and para) ESIPT-active chalcone dyes and have characterized their photophysical properties in polar protic solvents (MeOH and glycerol (Gly)/MeOH mixtures) and a nonpolar aprotic (1,4-dioxane) solvent for comparison. The chalcones favor a GS E structure, which undergoes ESIPT in MeOH, Gly/MeOH mixtures, and dioxane to exclusively afford K emission with large Stokes shifts. The o-isomers possess expanded π-conjugation compared to their p-isomer counterparts, which diminishes their tendency to generate twisted intramolecular charge transfer (TICT) states. Consequently, the o-isomers have greater quantum yields and lack molecular rotor (MR) character with little K emission response to increased solvent viscosity. However, they possess strong positive solvatochromism, displaying significant blue wavelength shifts coupled with turn-on K emission in moving from polar protic MeOH to nonpolar dioxane. In contrast, the p-isomers display MR character with turn-on K emission in 75:25 Gly/MeOH compared to their emission in MeOH (up to 14-fold) due to a strong tendency for TICT. Mechanistic insight into the observed isomer-specific photophysical properties of the ESIPT-active chalcones was obtained through density functional theory (DFT) calculations. Implications for DNA biosensing applications are discussed.
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Affiliation(s)
- Keenan T Regan
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Austin Pounder
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Camille Lin
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Leanne D Chen
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Richard A Manderville
- Departments of Chemistry and Toxicology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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