Photophysics of 3-acetyl-4-oxo-6,7-dihydro-12H indolo-[2,3-a] quinolizine: emission from two states

Mallick, Arabinda; Maiti, Subhendu; Haldar, Basudeb; Purkayastha, Pradipta; Chattopadhyay, Nitin

doi:10.1016/s0009-2614(03)00358-0

Cited by 72 publications

(81 citation statements)

References 26 publications

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“…A remarkable red shift of the maximum emission wavelength was also observed, which was ascribed to an increase in the polarity of the protein environment compared to that of the pure protein solution. 12 And the structural behavior of the emission spectra with the addition of BAFP in tris buffer solution can be rationalized in terms of binding of the probe with the protein leading to a less polar microenvironment around the fluorophore. A significant intramolecular charge transfer character of the relevant transitions was expected for planar aromatic phenol, which was confirmed by the fact that the fluorescence spectra are broad and structural.…”

Section: Resultsmentioning

confidence: 99%

Interaction Study of 2,6‐Bis[4‐(4‐amino‐2‐trifluoromethyl phenoxy)benzoyl] Pyridine with Human Immunoglobulin by Optical Spectroscopy and Molecular Modeling

He¹,

Zhang

Gao

et al. 2009

Chin. J. Chem.

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The interaction between human immunoglobulin (HIgG) and BAFP (2,6-bis[4-(4-amino-2-trifluoromethyl phenoxy)benzoyl] pyridine was studied by fluorescence quenching, Fourier transform infrared (FT-IR) spectra and molecule modeling. The synchronous fluorescence spectra indicated the information on qualitative changes of the protein secondary structure in the presence of BAFP in aqueous solution. The quantitative alterations of the protein secondary structure were estimated by the evidences from FT-IR spectra with increases of α helices by about 2.6%-10.2%, increases of β-sheet structure by about 13.6%-27.7%, and reductions of β-turn structure by about 23.8%-30.3%. Molecular docking suggests that BAFP can strongly bind to HIgG. There are four hydrogen bond interactions between the drug and the residues Trp 170, Val 105, Met 139 and Asn 52. It was also considered that BAFP bound to HIgG mainly by a hydrophobic interaction, which is in good agreement with the results from the experimental thermodynamic parameters (the enthalpy change ∆H and the entropy change ∆S were calculated to be -6.70 kJ•mol -1 and 71.93 J•mol -1 •K -1 , respectively, according to the Van't Hoff equation).

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Section: Resultsmentioning

confidence: 99%

Interaction Study of 2,6‐Bis[4‐(4‐amino‐2‐trifluoromethyl phenoxy)benzoyl] Pyridine with Human Immunoglobulin by Optical Spectroscopy and Molecular Modeling

He¹,

Zhang

Gao

et al. 2009

Chin. J. Chem.

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“…17 Through a series of experiments we have already established that the fluorophore molecule serves as an excellent fluorescent probe for biological systems. [18][19][20][21][22][23] Given the broad range of biological activities of AODIQ, in the present study we have explored the FRET process operative between the tryptophan residue present in HSA and the AODIQ system in some detail.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence resonance energy transfer from tryptophan in human serum albumin to a bioactive indoloquinolizine system

et al. 2007

Self Cite

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The interaction between a bioactive molecule, 3-acetyl-4-oxo-6,7-dihydro-12H indolo-[2,3-a] quinolizine (AODIQ), with human serum albumin (HSA) has been studied using steady-state absorption and fluorescence techniques. A 1 : 1 complex formation has been established and the binding constant (K) and free energy change for the process have been reported. The AODIQ-HSA complex results in fluorescence resonance energy transfer (FRET) from the tryptophan moiety of HSA to the probe. The critical energy-transfer distance (R 0 ) for FRET and the Stern-Volmer constant (K sv ) for the fluorescence quenching of the donor in the presence of the acceptor have been determined. Importantly, K SV has been shown to be equal to the binding constant itself, implying that the fluorescence quenching arises only from the FRET process. The study suggests that the donor and the acceptor are bound to the same protein at different locations but within the quenching distance.

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“…It is evident that the addition of the drug causes a dramatic enhancement in the fluorescence emission intensity of HIgG accompanied by evident changes in its emission profile. A remarkable blue shift of the maximum emission wavelength was also observed, which is as- cribed to a lowering in the polarity of the protein environment compared to that of the pure protein solution [26] . Furthermore, the structural behavior of the emission spectra with the addition of guaiacol in Tris buffer solution can be rationalized in terms of the binding of the probe with the protein leading to a more polar microenvironment around the fluorophore.…”

Section: Binding Studies Using Fluorescence and Uv-vis Spectroscopymentioning

confidence: 83%

Molecular modeling and spectroscopic studies on the binding of guaiacol to human immunoglobulin

Yao

Liu

et al. 2006

SCI CHINA SER B

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The fluorogenic property of guaiacol was exploited for the first time to analyze the interaction with target protein as a probe by molecular modeling, fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy. Molecular docking was performed to reveal the possible binding mode or mechanism and suggested that guaiacol can strongly bind to human immunoglobulin (HIgG). It is considered that guaiacol binds to HIgG mainly by a hydrophobic interaction and there are two hydrogen bond interactions between the drug and the residues LEU 80 and ASP 65, which is in good agreement with the results from the experimental thermodynamic parameters (the enthalpy change ΔH 0 and the entropy change ΔS 0 were calculated to be 65.55 kJ·mol −1 and 132.95 J·mol −1 ·K −1 according to the Vant' Hoff equation). Data obtained by the fluorescence spectroscopy indicated that binding of guaiacol with HIgG leads to dramatic enhancement in the fluorescence emission intensity along with significant occurrence of efficient Förster resonance energy transfer (FRET) from the residue of HIgG to the protein bound guaiacol. From the low value of fluorescence anisotropy (r = 0.06), it is argued that the probe molecule is located in the motionally unrestricted environment of the protein. The alterations of protein's secondary structure in the presence of guaiacol in aqueous solution were quantitatively calculated by the evidences from FT-IR and CD spectroscopes.

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Photophysics of 3-acetyl-4-oxo-6,7-dihydro-12H indolo-[2,3-a] quinolizine: emission from two states

Cited by 72 publications

References 26 publications

Interaction Study of 2,6‐Bis[4‐(4‐amino‐2‐trifluoromethyl phenoxy)benzoyl] Pyridine with Human Immunoglobulin by Optical Spectroscopy and Molecular Modeling

Interaction Study of 2,6‐Bis[4‐(4‐amino‐2‐trifluoromethyl phenoxy)benzoyl] Pyridine with Human Immunoglobulin by Optical Spectroscopy and Molecular Modeling

Fluorescence resonance energy transfer from tryptophan in human serum albumin to a bioactive indoloquinolizine system

Molecular modeling and spectroscopic studies on the binding of guaiacol to human immunoglobulin

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