1
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Shin JS, Jang Y, Kim DS, Jung E, Lee MK, Kim B, Ahn S, Shin Y, Jang SS, Yun CS, Yoo J, Lim YC, Han SB, Kim M. Inhibition of endocytic uptake of severe acute respiratory syndrome coronavirus 2 and endo-lysosomal acidification by diphenoxylate. Antimicrob Agents Chemother 2024:e0034124. [PMID: 38742905 DOI: 10.1128/aac.00341-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 04/17/2024] [Indexed: 05/16/2024] Open
Abstract
Cell culture-based screening of a chemical library identified diphenoxylate as an antiviral agent against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The observed 50% effective concentrations ranged between 1.4 and 4.9 µM against the original wild-type strain and its variants. Time-of-addition experiments indicated that diphenoxylate is an entry blocker targeting a host factor involved in viral infection. Fluorescence microscopic analysis visualized that diphenoxylate prevented SARS-CoV-2 particles from penetrating the cell membrane and also impaired endo-lysosomal acidification. Diphenoxylate exhibited a synergistic inhibitory effect on SARS-CoV-2 infection in human lung epithelial Calu-3 cells when combined with a transmembrane serine protease 2 (TMPRSS2) inhibitor, nafamostat. This synergy suggested that efficient antiviral activity is achieved by blocking both TMPRSS2-mediated early and endosome-mediated late SARS-CoV-2 entry pathways. The antiviral efficacy of diphenoxylate against SARS-CoV-2 was reproducible in a human tonsil organoids system. In a transgenic mouse model expressing the obligate SARS-CoV-2 receptor, human angiotensin-converting enzyme 2, intranasal administration of diphenoxylate (10 mg/kg/day) significantly reduced the viral RNA copy number in the lungs by 70% on day 3. This study underscores that diphenoxylate represents a promising core scaffold, warranting further exploration for chemical modifications aimed at developing a new class of clinically effective antiviral drugs against SARS-CoV-2.
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Affiliation(s)
- Jin Soo Shin
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Yejin Jang
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Dong-Su Kim
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Eunhye Jung
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Myoung Kyu Lee
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Byungil Kim
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Sunjoo Ahn
- Therapeutics and Biotechnology Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Yeonju Shin
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Su San Jang
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Chang Soo Yun
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Jongman Yoo
- CHA Organoid Research Center, CHA University, Seongnam, Gyeonggi-do, Republic of Korea
| | - Young Chang Lim
- Department of Otorhinolaryngology-Head and Neck Surgery, The Research Institute, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - Soo Bong Han
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
- Medicinal Chemistry and Pharmacology, University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Meehyein Kim
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
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2
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Zhang C, Balutowski A, Feng Y, Calderin JD, Fratti RA. High throughput analysis of vacuolar acidification. Anal Biochem 2022; 658:114927. [PMID: 36167157 DOI: 10.1016/j.ab.2022.114927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/09/2022] [Accepted: 09/20/2022] [Indexed: 11/15/2022]
Abstract
Eukaryotic cells are compartmentalized into membrane-bound organelles, allowing each organelle to maintain the specialized conditions needed for their specific functions. One of the features that change between organelles is lumenal pH. In the endocytic and secretory pathways, lumenal pH is controlled by isoforms and concentration of the vacuolar-type H+-ATPase (V-ATPase). In the endolysosomal pathway, copies of complete V-ATPase complexes accumulate as membranes mature from early endosomes to late endosomes and lysosomes. Thus, each compartment becomes more acidic as maturation proceeds. Lysosome acidification is essential for the breakdown of macromolecules delivered from endosomes as well as cargo from different autophagic pathways, and dysregulation of this process is linked to various diseases. Thus, it is important to understand the regulation of the V-ATPase. Here we describe a high-throughput method for screening inhibitors/activators of V-ATPase activity using Acridine Orange (AO) as a fluorescent reporter for acidified yeast vacuolar lysosomes. Through this method, the acidification of purified vacuoles can be measured in real-time in half-volume 96-well plates or a larger 384-well format. This not only reduces the cost of expensive low abundance reagents, but it drastically reduces the time needed to measure individual conditions in large volume cuvettes.
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Affiliation(s)
- Chi Zhang
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Adam Balutowski
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yilin Feng
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jorge D Calderin
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Rutilio A Fratti
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
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3
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Vener MV, Makhrov DE, Voronin AP, Shalafan DR. Molecular Dynamics Simulation of Association Processes in Aqueous Solutions of Maleate Salts of Drug-like Compounds: The Role of Counterion. Int J Mol Sci 2022; 23:ijms23116302. [PMID: 35682979 PMCID: PMC9181654 DOI: 10.3390/ijms23116302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 05/31/2022] [Accepted: 06/02/2022] [Indexed: 11/16/2022] Open
Abstract
The study of the formation of microstructures during the interaction of a protonated drug-like compound (API) with a maleic acid monoanion sheds light on the assembly processes in an aqueous solution at the molecular level. Molecular dynamics (MD) simulations coupled with density functional theory (DFT) calculations made it possible to find initial hydrogen bonding motifs during the assembly process, leading to the formation of heterodimers and trimers. The process of trimer formation [protonated API—maleic acid monoanion—protonated API] proceeds through the formation of three intermolecular H-bonds by the CO2− group of the maleic acid monoanion in both systems. The total enthalpy/energy of these H-bonds is more than 70 kJ/mol. Thus, the maleic acid monoanion plays a key role in the processes of association in aqueous solution, and the interaction of the maleic acid monoanion with API is more preferable than the interaction of API molecules with each other. DFT computations in the discrete continuum approximation reveal the spectral features of heterodimers and trimers, and the ATR-IR spectra confirmed these findings. MD simulations followed by DFT calculations made it possible to describe the initial stages of the formation of pharmaceutical cocrystals in an aqueous solution.
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Affiliation(s)
- Mikhail V. Vener
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii prosp. 31, 119991 Moscow, Russia
- Correspondence:
| | - Denis E. Makhrov
- Faculty of Natural Science, Mendeleev University of Chemical Technology, Miusskaya Square 9, 125047 Moscow, Russia;
| | - Alexander P. Voronin
- G.A. Krestov Institute of Solution Chemistry RAS, 153045 Ivanovo, Russia; (A.P.V.); (D.R.S.)
| | - Daria R. Shalafan
- G.A. Krestov Institute of Solution Chemistry RAS, 153045 Ivanovo, Russia; (A.P.V.); (D.R.S.)
- Ivanovo State University for Chemistry and Technology, 153000 Ivanovo, Russia
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4
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Diclofenac Ion Hydration: Experimental and Theoretical Search for Anion Pairs. Molecules 2022; 27:molecules27103350. [PMID: 35630826 PMCID: PMC9146526 DOI: 10.3390/molecules27103350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/15/2022] [Accepted: 05/17/2022] [Indexed: 11/21/2022] Open
Abstract
Self-assembly of organic ions in aqueous solutions is a hot topic at the present time, and substances that are well-soluble in water are usually studied. In this work, aqueous solutions of sodium diclofenac are investigated, which, like most medicinal compounds, is poorly soluble in water. Classical MD modeling of an aqueous solution of diclofenac sodium showed equilibrium between the hydrated anion and the hydrated dimer of the diclofenac anion. The assignment and interpretation of the bands in the UV, NIR, and IR spectra are based on DFT calculations in the discrete-continuum approximation. It has been shown that the combined use of spectroscopic methods in various frequency ranges with classical MD simulations and DFT calculations provides valuable information on the association processes of medical compounds in aqueous solutions. Additionally, such a combined application of experimental and calculation methods allowed us to put forward a hypothesis about the mechanism of the effect of diclofenac sodium in high dilutions on a solution of diclofenac sodium.
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Chattaraj KG, Paul S. Underlying Mechanisms of Allopurinol in Eliminating Renal Toxicity Induced by Melamine-Uric Acid Complex Formation: A Computational Study. Chem Res Toxicol 2021; 34:2054-2069. [PMID: 34410109 DOI: 10.1021/acs.chemrestox.1c00145] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using molecular dynamics, we address uric acid (UA) replacement by a model small-molecule inhibitor, allopurinol (AP), from its aggregated cluster in a columnar fashion. Experimentally it has been affirmed that AP is efficient in preventing UA-mediated renal stone formation. However, no study has presented the underlying mechanisms yet. Hence, a theoretical approach is presented for mapping the AP, which binds to melamine (MM) and UA clusters. In AP's presence, the higher-order cluster of UA molecules turns into a lower-order cluster, which "drags" fewer MM to them. Consequently, the MM-UA composite structure gets reduced. It is worth noting that UA-AP and AP-MM hydrogen-bonding interactions often play an essential role in reducing the UA-MM cluster size. Interestingly, an AP around UA makes a pillar-like structure, confirmed by defining the point-plane distribution function. The decomposition of the preferential interaction by Kirkwood-Buff integral into different angles like 0°-30°, 30°-60°, and 60°-90° firmly establishes the phenomenon mentioned above. However, the structural order for such π-stacking interactions between AP and UA molecules is not hierarchical but rather more spontaneous. The driving force behind UA-AP-MM composite formation is the favorable complexation energy that can be inferred by computing pairwise binding free energies for all possible combinations. Performing enhanced sampling and quantum calculations further confirms the evidence for UA degradation.
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Affiliation(s)
| | - Sandip Paul
- Department of Chemistry, Indian Institute of Technology, Guwahati Assam-781039, India
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6
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Chattaraj KG, Paul S. Investigation on the Mechanisms of Synchronous Interaction of K 3Cit with Melamine and Uric Acid That Avoids the Formation of Large Clusters. J Chem Inf Model 2020; 60:4827-4844. [PMID: 32786693 DOI: 10.1021/acs.jcim.0c00384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Uric acid (UA) has an enormous competence to aggregate over melamine (Mel), producing large UA clusters that "drag" Mel toward them. Such a combination of donor-acceptor pairs provides a robust Mel-UA composite, thereby denoting a high complexity. Thus, a straightforward but pragmatic methodology might indeed require either destruction of the aggregation of UA or impediment of the hydrogen-bonded cluster of Mel and UA. Here, potassium citrate (K3Cit) is used as a potent inhibitor for a significant decrease of large UA-Mel clusters. The underlying mechanisms of synchronous interactions between K3Cit and the Mel-UA pair are examined by the classical molecular dynamics simulation coupled with the enhanced sampling method. K3Cit binds to the Mel-UA pair profoundly to produce a Mel-UA-K3Cit complex with favorable complexation energy (as indicated by the reckoning of pairwise ΔGbind° employing the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method). The strength of interaction follows the order UA-K3Cit > Mel-K3Cit > Mel-UA, thus clearly demonstrating the instability caused by upsetting the π-stacking of UA and hydrogen bonding of Mel-UA simultaneously. The comprehensive, strategically designed "direct approach" and "indirect approach" cluster structure analysis shows that K3Cit reduces the direct approach Mel-UA cluster size significantly irrespective of ensemble variation. Furthermore, the estimation of potentials of mean force (PMFs) reveals that the (UA)decamer-Mel interaction prevails over (UA)tetramer-Mel. The dynamic property (dimer existence autocorrelation functions) proves the essence of dimerization between Mel and UA in the absence and presence of K3Cit. Moreover, the calculation of the preferential interaction parameter provides the concentration at which Mel-K3Cit and UA-K3Cit interactions are predominant over the interaction of Mel and UA.
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Affiliation(s)
- Krishna Gopal Chattaraj
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Sandip Paul
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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7
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Bose A, Chowdhury R, Nandi S, Raja SO, Ray S, Bhattacharyya K, Dasgupta AK. Time-dependent enhancement of fluorescence from Rhodobacter capsulatus SB1003 and its critical dependence on concentration temperature and static magnetic field. J Biol Phys 2020; 46:151-167. [PMID: 32193688 DOI: 10.1007/s10867-020-09545-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 03/02/2020] [Indexed: 11/28/2022] Open
Abstract
Continuous exposure of 395 nm light increases the fluorescence emission intensity of photosynthetic purple non-sulphur bacteria, Rhodobacter capsulatus (SB1003). We show that such an increase in fluorescence emission of extracellular pigment complexes (PC) from these photosynthetic bacteria depends on the concentration of the pigment and temperature and can also be modulated by the static magnetic field. The time-dependent enhanced emission disappears either at or below 300 K or below a threshold sample concentration (0.1 mg/ml). The enhanced emission reappears at this condition (T < 278 K) if a static magnetic field (395 mT) is introduced during fluorescence measurement. The time dependence of emission is expressed in terms of a first-order rate constant, k = dF/(Fdt). The sign of k shifts from positive to negative as PC concentration is lowered than a threshold value, implying onset of fluorescence decay (k < 0) rather than amplification (k > 0). At PC concentration higher than a threshold, k becomes negative if the temperature is lowered. But, surprisingly, at low temperature, a static magnetic field reverts the k value to positive. We explain the logical nature of k-switching and photo-dynamics of the aforesaid microbial fluorescence emission by aggregation of protoporphyrin rings present in the PC. While the simultaneous presence of decay in fluorescence and susceptibility to static magnetic field suggests the dominance of triplet states at low temperatures, the process is reversed by SMF-induced removal of spin degeneracy. At higher temperatures, the optical excitability and lack of magnetic response suggest the dominance of singlet states. We propose that the restructuring of the singlet-triplet distribution by intersystem crossing may be the basis of this logical behaviour. In context with microbial function, time-dependent enhancement of fluorescence also implies relay of red photons to the neighbouring microbes not directly exposed to the incident radiation, thus serving as an indirect photosynthetic regulator.
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Affiliation(s)
- Anirban Bose
- Department of Biochemistry, University of Calcutta, Kolkata, India
| | - Rajdeep Chowdhury
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata, India
| | - Somen Nandi
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata, India
| | - Sufi O Raja
- Department of Physics, Duke University, Durham, NC, USA
| | - Sanhita Ray
- Department of Biochemistry, University of Calcutta, Kolkata, India
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8
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Mondal P, Chowdhury R, Nandi S, Amin MA, Bhattacharyya K, Ghosh S. Probing Deviation of Adhered Membrane Dynamics between Reconstituted Liposome and Cellular System. Chem Asian J 2019; 14:4616-4624. [PMID: 31210021 DOI: 10.1002/asia.201900588] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 06/10/2019] [Indexed: 01/22/2023]
Abstract
The dynamics of cell-cell adhesion are complicated due to complexities in cellular interactions and intra-membrane interactions. In the present work, we have reconstituted a liposome-based model system to mimic the cell-cell adhesion process. Our model liposome system consists of one fluorescein-tagged and one TRITC (tetramethyl-rhodamine isothiocyanate)-tagged liposome, adhered through biotin-neutravidin interaction. We monitored the adhesion process in liposomes using Förster Resonance Energy Transfer (FRET) between fluorescein (donor) and TRITC (acceptor). Occurrence of FRET is confirmed by the decrease in donor lifetime as well as distinct rise time of the acceptor fluorescence. Interestingly, the acceptor's emission exhibits fluctuations in the range of ≈3±1 s. This may be attributed to structural oscillations associated in two adhered liposomes arising from the flexible nature of biotin-neutravidin interaction. We have compared the dynamics in a cell-mimicking liposome system with that in an in vitro live cell system. In the adhered live cell system, we used CPM (7-diethylamino-3-(4-maleimido-phenyl)-4-methylcoumarin, donor) and nile red (acceptor), which are known to stain the membrane of CHO (Chinese Hamster Ovary) cells. The dynamics of the adhered membranes of two live CHO cells were observed through FRET between CPM and nile red. The acceptor fluorescence intensity exhibits an oscillation in the time-scale of ≈1±0.75 s, which is faster compared to the reconstituted liposome system, indicating the contributions and involvement of multiple dynamic protein complexes around the cell membrane. This study offers simple reconstituted model systems to understand the complex membrane dynamics using a FRET-based physical chemistry approach.
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Affiliation(s)
- Prasenjit Mondal
- Organic & Medicinal Chemistry Division, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata-, 700032, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-, 201002, India
| | - Rajdeep Chowdhury
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-, 700032, India.,Present Address: Texas A&M Health Science Center, College of Medicine, Bryan, TX 77807, USA
| | - Somen Nandi
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-, 700032, India
| | - Md Asif Amin
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-, 700032, India
| | | | - Surajit Ghosh
- Organic & Medicinal Chemistry Division, Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata-, 700032, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-, 201002, India
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9
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Nandi S, Parui S, Jana B, Bhattacharyya K. Local environment of organic dyes in an ionic liquid-water mixture: FCS and MD simulation. J Chem Phys 2018; 149:054501. [DOI: 10.1063/1.5027458] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Somen Nandi
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Sridip Parui
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Biman Jana
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Kankan Bhattacharyya
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal 462066, Madhya Pradesh, India
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10
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Nandi S, Ghosh S, Bhattacharyya K. Live Cell Microscopy: A Physical Chemistry Approach. J Phys Chem B 2018; 122:3023-3036. [PMID: 29389140 DOI: 10.1021/acs.jpcb.7b11689] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Probing dynamics of intracellular components using physical chemistry techniques is a remarkable bottom-up approach for understanding the structures and functions of a biological cell. In this "Feature Article", we give an overview on local polarity, solvation, viscosity, acid-base property, red-ox processes (thiol-disulfide exchange), and gene silencing at selected intracellular components inside a live cell. Significant differences have been observed between cancer cells and their noncancer counterparts. We demonstrate that thiol-disulfide exchange, calcium oscillation, and gene silencing are manifested in time dependence of fluorescence intensity. We show that fluorescent gold nanoclusters may be used in drug delivery (e.g., doxorubicin) and selective killing of cancer cells. Further, we discuss dynamics and structural changes of DNA quadruplexes and i-motifs, induced by different external conditions (e.g., pH) and additives (e.g., K+ and other target specific small molecules). We demonstrate that peptidomimetic analogues have high specificity over double-stranded DNA for binding with i-motifs and G-quadruplexes. These results may have significant biological implications.
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Affiliation(s)
- Somen Nandi
- Department of Physical Chemistry , Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032 , India
| | - Surajit Ghosh
- Organic & Medicinal Chemistry Division , CSIR-Indian Institute of Chemical Biology , 4, Raja S. C. Mullick Road , Jadavpur, Kolkata , 700 032 West Bengal , India.,Academy of Scientific and Innovative Research (AcSIR) , CSIR-Indian Institute of Chemical Biology Campus , 4 Raja S. C. Mullick Road , Jadavpur, Kolkata 700 032 , India
| | - Kankan Bhattacharyya
- Department of Chemistry , Indian Institute of Science Education and Research Bhopal , Bhopal , 462 066 Madhya Pradesh , India
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11
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Das G, Chattoraj S, Nandi S, Mondal P, Saha A, Bhattacharyya K, Ghosh S. Probing the conformational dynamics of photosystem I in unconfined and confined spaces. Phys Chem Chem Phys 2018; 20:449-455. [DOI: 10.1039/c7cp07375e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PSI demonstrates strong fluctuations in fluorescence intensity and lifetime with two conformational states in bulk-water in contrast to a liposome.
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Affiliation(s)
- Gaurav Das
- Organic & Medicinal Chemistry Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata-700032
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Shyamtanu Chattoraj
- Department of Physical Chemistry
- Indian Association for the Cultivation of Science
- Kolkata 700032
- India
| | - Somen Nandi
- Department of Physical Chemistry
- Indian Association for the Cultivation of Science
- Kolkata 700032
- India
| | - Prasenjit Mondal
- Organic & Medicinal Chemistry Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata-700032
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Abhijit Saha
- Organic & Medicinal Chemistry Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata-700032
- India
| | - Kankan Bhattacharyya
- Department of Chemistry
- Indian Institute of Science Education & Research Bhopal
- Bhopal Bypass Road
- Bhopal-462 066
- India
| | - Surajit Ghosh
- Organic & Medicinal Chemistry Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata-700032
- India
- Academy of Scientific and Innovative Research (AcSIR)
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12
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Ghosh C, Nandi S, Bhattacharyya K. Probing micro-environment of lipid droplets in a live breast cell: MCF7 and MCF10A. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2016.12.068] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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13
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Ghosh S, Nandi S, Ghosh C, Bhattacharyya K. Fluorescence Dynamics in the Endoplasmic Reticulum of a Live Cell: Time-Resolved Confocal Microscopy. Chemphyschem 2016; 17:2818-23. [PMID: 27245117 DOI: 10.1002/cphc.201600425] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Indexed: 11/11/2022]
Abstract
Fluorescence dynamics in the endoplasmic reticulum (ER) of a live non-cancer lung cell (WI38) and a lung cancer cell (A549) are studied by using time-resolved confocal microscopy. To selectively study the organelle, ER, we have used an ER-Tracker dye. From the emission maximum (λmaxem) of the ER-Tracker dye, polarity (i.e. dielectric constant, ϵ) in the ER region of the cells (≈500 nm in WI38 and ≈510 nm in A549) is estimated to be similar to that of chloroform (λmaxem =506 nm, ϵ≈5). The red shift by 10 nm in λmaxem in the cancer cell (A549) suggests a slightly higher polarity compared to the non-cancer cell (WI38). The fluorescence intensity of the ER-Tracker dye exhibits prolonged intermittent oscillations on a timescale of 2-6 seconds for the cancer cell (A549). For the non-cancer cell (WI38), such fluorescence oscillations are much less prominent. The marked fluorescence intensity oscillations in the cancer cell are attributed to enhanced calcium oscillations. The average solvent relaxation time (<τs >) of the ER region in the lung cancer cell (A549, 250±50 ps) is about four times faster than that in the non-cancer cell (WI38, 1000±50 ps).
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Affiliation(s)
- Shirsendu Ghosh
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India), Fax: (91)-33-2473-2805
| | - Somen Nandi
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India), Fax: (91)-33-2473-2805
| | - Catherine Ghosh
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India), Fax: (91)-33-2473-2805
| | - Kankan Bhattacharyya
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700 032, India), Fax: (91)-33-2473-2805.
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14
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Nandi S, Mondal P, Chowdhury R, Saha A, Ghosh S, Bhattacharyya K. Amyloid beta peptides inside a reconstituted cell-like liposomal system: aggregation, FRET, fluorescence oscillations and solvation dynamics. Phys Chem Chem Phys 2016; 18:30444-30451. [DOI: 10.1039/c6cp06143e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aggregation dynamics of Aβ peptides were studied inside a reconstituted cell-mimic liposomal system using FRET and FCS at various depths starting from the membrane to the core of the liposome.
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Affiliation(s)
- Somen Nandi
- Department of Physical Chemistry
- Indian Association for the Cultivation of Science
- Kolkata 700032
- India
| | - Prasenjit Mondal
- Organic and Medicinal Chemistry Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata-700032
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Rajdeep Chowdhury
- Department of Physical Chemistry
- Indian Association for the Cultivation of Science
- Kolkata 700032
- India
| | - Abhijit Saha
- Organic and Medicinal Chemistry Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata-700032
- India
| | - Surajit Ghosh
- Organic and Medicinal Chemistry Division
- CSIR-Indian Institute of Chemical Biology
- Kolkata-700032
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Kankan Bhattacharyya
- Department of Physical Chemistry
- Indian Association for the Cultivation of Science
- Kolkata 700032
- India
| |
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