1
|
Truksa J, Kratochvíl M, Richtár J, Ivanová L, Weiter M, Krajčovič J, Lukeš V. Spectroscopic behavior differences between lumazine and alloxazine in the DMSO-water mixture. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 302:122998. [PMID: 37356394 DOI: 10.1016/j.saa.2023.122998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/19/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
The absorption and emission spectra were investigated for lumazine, alloxazine and their cyanated or fluorinated derivatives, respectively. The spectroscopic properties were modulated by varying water concentration in dimethyl sulfoxide (DMSO). Some intriguing experimental results were found for the samples containing 65 % of water and 35% of DMSO. This finding is consistent with previously published molecular dynamics (MD) simulations confirming the concept of the 'local bulk' model. In this case, a notable decrease in absorption and emission intensities was registered, even larger than the water quenching observed in other cases. The changes in midrange DMSO concentrations could be explained by the formation of local solvents structures as predicted by MD, specifically the formation of DMSO·2H2O dimers. Experimentally, the cyano-substituted lumazine has shown a remarkable sensitivity to DMSO concentration. The spectroscopic measurements were interpreted using the density functional theory where the implicit DMSO solvent model was combined with explicit water molecules. Together with its enhanced water solubility, the cyanated lumazine derivate could be used for non-destructive DMSO detection in vitro for applications such as drug uptake monitoring, since DMSO is often used in pharmaceutical practice.
Collapse
Affiliation(s)
- Jan Truksa
- Faculty of Chemistry, Brno University of Technology, Purkyňova 118, CZ-612 00 Brno, Czech Republic.
| | - Matouš Kratochvíl
- Faculty of Chemistry, Brno University of Technology, Purkyňova 118, CZ-612 00 Brno, Czech Republic
| | - Jan Richtár
- Faculty of Chemistry, Brno University of Technology, Purkyňova 118, CZ-612 00 Brno, Czech Republic
| | - Lucia Ivanová
- Faculty of Chemistry, Brno University of Technology, Purkyňova 118, CZ-612 00 Brno, Czech Republic
| | - Martin Weiter
- Faculty of Chemistry, Brno University of Technology, Purkyňova 118, CZ-612 00 Brno, Czech Republic
| | - Jozef Krajčovič
- Faculty of Chemistry, Brno University of Technology, Purkyňova 118, CZ-612 00 Brno, Czech Republic; Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, via Orabona, 4-70125 Bari, Italy
| | - Vladimír Lukeš
- Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37 Bratislava, Slovakia
| |
Collapse
|
2
|
Intrinsically Fluorescent Anti-Cancer Drugs. BIOLOGY 2022; 11:biology11081135. [PMID: 36009762 PMCID: PMC9405238 DOI: 10.3390/biology11081135] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022]
Abstract
At present, about one-third of the total protein targets in the pharmaceutical research sector are kinase-based. While kinases have been attractive targets to combat many diseases, including cancer, selective kinase inhibition has been challenging, because of the high degree of structural homology in the active site where many kinase inhibitors bind. Despite efficacy as cancer drugs, kinase inhibitors can exhibit limited target specificity and rationalizing their target profiles in the context of precise molecular mechanisms or rearrangements is a major challenge for the field. Spectroscopic approaches such as infrared, Raman, NMR and fluorescence have the potential to provide significant insights into drug-target and drug-non-target interactions because of sensitivity to molecular environment. This review places a spotlight on the significance of fluorescence for extracting information related to structural properties, discovery of hidden conformers in solution and in target-bound state, binding properties (e.g., location of binding sites, hydrogen-bonding, hydrophobicity), kinetics as well as dynamics of kinase inhibitors. It is concluded that the information gleaned from an understanding of the intrinsic fluorescence from these classes of drugs may aid in the development of future drugs with improved side-effects and less disease resistance.
Collapse
|
3
|
Husain S, Mehata MS, Pandey N, Mishra H, Pant S. Reinvestigation of the photophysics of 3-aminobenzoic acid in neat and mixed binary solvents. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 247:119100. [PMID: 33212332 DOI: 10.1016/j.saa.2020.119100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
The present study elucidates the reinvestigation of the photophysical behavior of 3-aminobenzoic acid (3ABA) in solvents of different polarities using the steady-state spectroscopic techniques. Kamlet-Taft and Catalan solvatochromic models have been used to analyze the solvatochromic changes in neat solvents. The hydrogen bond donating ability of the solvent was found to be the main parameter affecting the spectral behavior of 3ABA. The solvatochromic characteristics of 3ABA have also been examined in binary solvent mixtures viz. acetonitrile (ACN)-methanol (MeOH) and benzene (BEN)-MeOH using the concept of preferential solvation. The preferential solvation of 3ABA shows unusual behavior for BEN-MeOH binary mixture and described unnoticed sigmoidal behavior in the ground state and synergistic impact in the excited state. Besides, the 3ABA was studied theoretically by quantum chemical calculations using (HF) Hartree-Fock and (DFT/B3LYP) density functional theories and its electronic absorption bands have been assigned by time-dependent density functional theory (TD-DFT). The effect of solvents on 3ABA was considered using a IEF-PCM-TDDFT (integral equation formalism of the polarizable continuum model- TDDFT) method. Thus, the theoretical results were found to be closer to the experimental results.
Collapse
Affiliation(s)
- Shahid Husain
- Photophysics Laboratory, Department of Physics, Centre of Advanced Study, DSB Campus, Kumaun University, Nainital 263002, India
| | - Mohan Singh Mehata
- Laser Spectroscopy Laboratory, Department of Applied Physics, Delhi Technological University, Bawana Road, Delhi 110042, India.
| | - Nupur Pandey
- Photophysics Laboratory, Department of Physics, Centre of Advanced Study, DSB Campus, Kumaun University, Nainital 263002, India
| | - Hirdyesh Mishra
- Physics Section, M.M.V., Banaras Hindu University (B.H.U.), Varanasi 221005, India
| | - Sanjay Pant
- Photophysics Laboratory, Department of Physics, Centre of Advanced Study, DSB Campus, Kumaun University, Nainital 263002, India
| |
Collapse
|
4
|
Khattab M, Wang F, Clayton AHA. Conformational Plasticity in Tyrosine Kinase Inhibitor-Kinase Interactions Revealed with Fluorescence Spectroscopy and Theoretical Calculations. J Phys Chem B 2018; 122:4667-4679. [PMID: 29629773 DOI: 10.1021/acs.jpcb.8b01530] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To understand drug-protein dynamics, it is necessary to account for drug molecular flexibility and binding site plasticity. Herein, we exploit fluorescence from a tyrosine kinase inhibitor, AG1478, as a reporter of its conformation and binding site environment when complexed with its cognate kinase. Water-soluble kinases, aminoglycoside phosphotransferase APH(3')-Ia and mitogen-activated protein kinase 14 (MAPK14), were chosen for this study. On the basis of our prior work, the AG1478 conformation (planar or twisted) was inferred from the fluorescence excitation spectrum and the polarity of the AG1478-binding site was deduced from the fluorescence emission spectrum, while red-edge excitation shift (REES) probed the heterogeneity of the binding site (protein conformation and hydration) distributions in the protein conformational ensemble. In the AG1478-APH(3')-Ia complex, both twisted (or partially twisted) and planar AG1478 conformations were evidenced from emission wavelength-dependent excitation spectra. The binding site environment provided by APH(3')-Ia was moderately polar (λmax = 480 nm) with evidence for considerable heterogeneity (REES = 34 nm). In contrast, in the AG1478-MAPK14 complex, AG1478 was in a predominantly planar conformation with a lower degree of conformational heterogeneity. The binding site environment provided by the MAPK14 protein was of relatively low polarity (λmax = 430 nm) with a smaller degree of heterogeneity (REES = 11 nm). The results are compared with the available X-ray data and discussed in the context of our current understanding of tyrosine kinase inhibitor conformation and protein conformational ensembles.
Collapse
|
5
|
Khattab M, Wang F, Clayton AHA. A pH-induced conformational switch in a tyrosine kinase inhibitor identified by electronic spectroscopy and quantum chemical calculations. Sci Rep 2017; 7:16271. [PMID: 29176733 PMCID: PMC5701190 DOI: 10.1038/s41598-017-16583-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/14/2017] [Indexed: 01/18/2023] Open
Abstract
Tyrosine kinase inhibitors (TKIs) are a major class of drug utilised in the clinic. During transit to their cognate kinases, TKIs will encounter different pH environments that could have a major influence on TKI structure. To address this, we report UV-Vis spectroscopic and computational studies of the TKI, AG1478, as a function of pH. The electronic absorption spectrum of AG1478 shifted by 10 nm (from 342 nm to 332 nm) from acid to neutral pH and split into two peaks (at 334 nm and 345 nm) in highly alkaline conditions. From these transitions, the pKa value was calculated as 5.58 ± 0.01. To compute structures and spectra, time-dependent density functional theory (TD-DFT) calculations were performed along with conductor-like polarizable continuum model (CPCM) to account for implicit solvent effect. On the basis of the theoretical spectra, we could assign the AG1478 experimental spectrum at acidic pH to a mixture of two twisted conformers (71% AG1478 protonated at quinazolyl nitrogen N(1) and 29% AG1478 protonated at quinazolyl nitrogen N(3)) and at neutral pH to the neutral planar conformer. The AG1478 absorption spectrum (pH 13.3) was fitted to a mixture of neutral (70%) and NH-deprotonated species (30%). These studies reveal a pH-induced conformational transition in a TKI.
Collapse
Affiliation(s)
- Muhammad Khattab
- Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria, 3122, Australia
| | - Feng Wang
- Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria, 3122, Australia.
- School of Chemistry (Bio21 Institute), University of Melbourne, Parkville, Victoria, 3052, Australia.
- School of Physics, University of Melbourne, Parkville, Victoria, 3052, Australia.
| | - Andrew H A Clayton
- Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria, 3122, Australia.
| |
Collapse
|