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Maiti J, Biswas S, Chaudhuri A, Chakraborty S, Chakraborty S, Das R. Environment sensitive fluorescent analogue of biologically active oxazoles differentially recognizes human serum albumin and bovine serum albumin: Photophysical and molecular modeling studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 175:191-199. [PMID: 28039847 DOI: 10.1016/j.saa.2016.12.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 11/24/2016] [Accepted: 12/20/2016] [Indexed: 06/06/2023]
Abstract
An environment sensitive fluorophore, 4-(5-(4-(dimethylamino)phenyl)oxazol-2-yl)benzoic acid (DMOBA), that closely mimics biologically active 2,5-disubstituited oxazoles has been designed to probe two homologous serum proteins, human serum albumin (HSA) and bovine serum albumin (BSA) by means of photophysical and molecular modeling studies. This fluorescent analogue exhibits solvent polarity sensitive fluorescence due to an intramolecular charge transfer in the excited state. In comparison to water, the steady state emission spectra of DMOBA in BSA is characterized by a greater blue shift (~10nm) and smaller Stokes' shift (~5980cm-1) in BSA than HSA (Stokes'shift~6600cm-1), indicating less polar and more hydrophobic environment of the dye in the former than the latter. The dye-protein binding interactions are remarkably stronger for BSA than HSA which is evident from higher value of the association constant for the DMOBA-BSA complex (Ka~5.2×106M-1) than the DMOBA-HSA complex (Ka~1.0×106M-1). Fӧrster resonance energy transfer studies revealed remarkably less efficient energy transfer (8%) between the donor tryptophans in BSA and the acceptor DMOBA dye than that (30%) between the single tryptophan moiety in HSA and the dye, which is consistent with a much larger distance between the donor (tryptophan)-acceptor (dye) pair in BSA (34.5Å) than HSA (25.4Å). Site specific competitive binding assays have confirmed on the location of the dye in Sudlow's site II of BSA and in Sudlow's site I of HSA, respectively. Molecular modeling studies have shown that the fluorescent analogue is tightly packed in the binding site of BSA due to strong steric complementarity, where, binding of DMOBA to BSA is primarily dictated by the van der Waals and hydrogen bonding interactions. In contrast, in HSA the steric complementarity is less significant and binding is primarily guided by polar interactions and van der Waals interactions appear to be less significant in the formation of the HSA-DMOBA complex. Electrostatic interactions contribute significantly in the binding of DMOBA to HSA (-2.09kcal/mol) compared to BSA (-0.47kcal/mol). Electrostatic surface potential calculation reveals that the DMOBA binding site within HSA is highly charged compared to BSA.
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Affiliation(s)
- Jyotirmay Maiti
- Department of Chemistry, West Bengal State University, Barasat, Kol-126, India
| | - Suman Biswas
- Department of Chemistry, West Bengal State University, Barasat, Kol-126, India
| | - Ankur Chaudhuri
- Department of Microbiology, West Bengal State University, Barasat, Kol-126, India
| | - Sandipan Chakraborty
- Department of Microbiology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, India
| | - Sibani Chakraborty
- Department of Microbiology, West Bengal State University, Barasat, Kol-126, India
| | - Ranjan Das
- Department of Chemistry, West Bengal State University, Barasat, Kol-126, India.
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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: 23] [Impact Index Per Article: 2.9] [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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Roy A, Kundu N, Banik D, Sarkar N. Comparative Fluorescence Resonance Energy-Transfer Study in Pluronic Triblock Copolymer Micelle and Niosome Composed of Biological Component Cholesterol: An Investigation of Effect of Cholesterol and Sucrose on the FRET Parameters. J Phys Chem B 2015; 120:131-42. [PMID: 26672631 DOI: 10.1021/acs.jpcb.5b09761] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arpita Roy
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, West Bengal, India
| | - Niloy Kundu
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, West Bengal, India
| | - Debasis Banik
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, West Bengal, India
| | - Nilmoni Sarkar
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, West Bengal, India
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Wazawa T, Morimoto N, Nagai T, Suzuki M. Rotational motion of rhodamine 6G tethered to actin through oligo(ethylene glycol) linkers studied by frequency-domain fluorescence anisotropy. Biophys Physicobiol 2015; 12:87-102. [PMID: 27493858 PMCID: PMC4736842 DOI: 10.2142/biophysico.12.0_87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 11/02/2015] [Indexed: 12/01/2022] Open
Abstract
Investigation of the rotational motion of a fluorescent probe tethered to a protein helps to elucidate the local properties of the solvent and protein near the conjugation site of the probe. In this study, we have developed an instrument for frequency-domain fluorescence (FDF) anisotropy measurements, and studied how the local properties around a protein, actin, can be elucidated from the rotational motion of a dye tethered to actin. Rhodamine 6G (R6G) was attached to Cys-374 using newly-synthesized R6G-maleimide with three different oligo(ethylene glycol) (OEG) linker lengths. The time-resolved anisotropy decay of R6G tethered to G-actin was revealed to be a combination of the two modes of the wobbling motion of R6G and the tumbling motion of G-actin. The rotational diffusion coefficient (RDC) of R6G wobbling was ~0.1 ns−1 at 20°C and increased with OEG linker length. The use of the three R6G-actin conjugates of different linker lengths was useful to not only figure out the linker length dependence of the rotational motion of R6G but also validate the analyses. In the presence of a cosolvent of glycerol, although the tumbling motion of G-actin was retarded in response to the bulk viscosity, the wobbling motion of R6G tethered to actin exhibited an increase of RDC as glycerol concentration increased. This finding suggests an intricate relationship between the fluid properties of the bulk solvent and the local environment around actin.
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Affiliation(s)
- Tetsuichi Wazawa
- Department of Biomolecular Science and Engineering, Institute for Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan; Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Nobuyuki Morimoto
- Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Takeharu Nagai
- Department of Biomolecular Science and Engineering, Institute for Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Makoto Suzuki
- Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
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Pospíšil P, Luxem KE, Ener M, Sýkora J, Kocábová J, Gray HB, Vlček A, Hof M. Fluorescence quenching of (dimethylamino)naphthalene dyes Badan and Prodan by tryptophan in cytochromes P450 and micelles. J Phys Chem B 2014; 118:10085-91. [PMID: 25079965 PMCID: PMC4148165 DOI: 10.1021/jp504625d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
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Fluorescence
of 2-(N,N-dimethylamino)-6-propionylnaphthalene
dyes Badan and Prodan is quenched by tryptophan in Brij 58 micelles
as well as in two cytochrome P450 proteins (CYP102, CYP119) with Badan
covalently attached to a cysteine residue. Formation of nonemissive
complexes between a dye molecule and tryptophan accounts for about
76% of the fluorescence intensity quenching in micelles, the rest
is due to diffusive encounters. In the absence of tryptophan, fluorescence
of Badan-labeled cytochromes decays with triexponential kinetics characterized
by lifetimes of about 100 ps, 700–800 ps, and 3 ns. Site mutation
of a histidine residue in the vicinity of the Badan label by tryptophan
results in shortening of all three decay lifetimes. The relative amplitude
of the fastest component increases at the expense of the two slower
ones. The average quenching rate constants are 4.5 × 108 s–1 (CYP102) and 3.7 × 108 s–1 (CYP119), at 288 K. Cyclic voltammetry of Prodan
in MeCN shows a reversible reduction peak at −1.85 V vs NHE
that becomes chemically irreversible and shifts positively upon addition
of water. A quasireversible reduction at −0.88 V was observed
in an aqueous buffer (pH 7.3). The excited-state reduction potential
of Prodan (and Badan) is estimated to vary from about +0.6 V (vs NHE)
in polar aprotic media (MeCN) to approximately +1.6 V in water. Tryptophan
quenching of Badan/Prodan fluorescence in CYPs and Brij 58 micelles
is exergonic by ≤0.5 V and involves tryptophan oxidation by
excited Badan/Prodan, coupled with a fast reaction between the reduced
dye and water. Photoreduction is a new quenching mechanism for 2-(N,N-dimethylamino)-6-propionylnaphthalene
dyes that are often used as solvatochromic polarity probes, FRET donors
and acceptors, as well as reporters of solvation dynamics.
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Affiliation(s)
- Petr Pospíšil
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 3, CZ-182 23 Prague, Czech Republic
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Arya S, Mukhopadhyay S. Ordered Water within the Collapsed Globules of an Amyloidogenic Intrinsically Disordered Protein. J Phys Chem B 2014; 118:9191-8. [DOI: 10.1021/jp504076a] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Shruti Arya
- Department of Chemical Sciences and ‡Department of
Biological Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Knowledge City, Sector
81, S.A.S. Nagar, Mohali 140306, Punjab, India
| | - Samrat Mukhopadhyay
- Department of Chemical Sciences and ‡Department of
Biological Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Knowledge City, Sector
81, S.A.S. Nagar, Mohali 140306, Punjab, India
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Datta S, Halder M. Detailed Scrutiny of the Anion Receptor Pocket in Subdomain IIA of Serum Proteins toward Individual Response to Specific Ligands: HSA-Pocket Resembles Flexible Biological Slide-Wrench Unlike BSA. J Phys Chem B 2014; 118:6071-85. [DOI: 10.1021/jp501547r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Shubhashis Datta
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Mintu Halder
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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Chaudhuri S, Batabyal S, Polley N, Pal SK. Vitamin B2 in Nanoscopic Environments under Visible Light: Photosensitized Antioxidant or Phototoxic Drug? J Phys Chem A 2014; 118:3934-43. [DOI: 10.1021/jp502904r] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Siddhi Chaudhuri
- Department
of Chemical, Biological
and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
| | - Subrata Batabyal
- Department
of Chemical, Biological
and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
| | - Nabarun Polley
- Department
of Chemical, Biological
and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
| | - Samir Kumar Pal
- Department
of Chemical, Biological
and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India
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Batabyal S, Mondol T, Choudhury S, Mazumder A, Pal SK. Ultrafast interfacial solvation dynamics in specific protein DNA recognition. Biochimie 2013; 95:2168-76. [DOI: 10.1016/j.biochi.2013.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 08/06/2013] [Indexed: 12/14/2022]
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Saha R, Rakshit S, Pal SK. Molecular recognition of a model globular protein apomyoglobin by synthetic receptor cyclodextrin: effect of fluorescence modification of the protein and cavity size of the receptor in the interaction. J Mol Recognit 2013; 26:568-77. [DOI: 10.1002/jmr.2301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 07/17/2013] [Accepted: 07/30/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Ranajay Saha
- Department of Chemical, Biological and Macromolecular Sciences; S.N. Bose National Centre for Basic Sciences; Block JD, Sector III Salt Lake Kolkata 700098 India
| | - Surajit Rakshit
- Department of Chemical, Biological and Macromolecular Sciences; S.N. Bose National Centre for Basic Sciences; Block JD, Sector III Salt Lake Kolkata 700098 India
| | - Samir Kumar Pal
- Department of Chemical, Biological and Macromolecular Sciences; S.N. Bose National Centre for Basic Sciences; Block JD, Sector III Salt Lake Kolkata 700098 India
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A Potential Carcinogenic Pyrene Derivative under Förster Resonance Energy Transfer to Various Energy Acceptors in Nanoscopic Environments. Chemphyschem 2013; 14:3581-93. [DOI: 10.1002/cphc.201300568] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Indexed: 11/07/2022]
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