Photophysics of indole derivatives: experimental resolution of L   a    and L   b    transitions and comparison with theory

Eftink, Maurice R.; Selvidge, LeRoy A.; Callis, Patrik R.; Rehms, Aden A.

doi:10.1117/12.17724

Cited by 23 publications

(32 citation statements)

References 16 publications

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“…Such a placement should cause the single-exponential lifetime differences between conformers to increase. We have considered cases in which a carboxylic group was placed directly at C-4 or C-5;lo possible complications due to 'La emission fromany of the selected conformers should be absent with polar substitution on the benzene side of the indole.1s- 21 We in fact did observe reduced and significantly different lifetimes for different conformers of 4-indole Abstract published in Advance ACS Abstracts, February 1, 1994.…”

Section: Introductionmentioning

confidence: 93%

Fluorescence lifetimes of substituted indoles in solution and in free jets: evidence for intramolecular charge-transfer quenching

Arnold¹,

Tong²,

Sulkes³

1994

J. Phys. Chem.

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Fluorescence lifetime measurements for a variety of substituted indoles were taken in cyclohexane and in supersonic gas expansions. When the two data sets were compared, a strong trend became evident. Solvent polarizability effects can be seen as stabilizing intramolecular charge-transfer quenching processes in the substituted indoles that are stimulated by the correct placement of charge accepting/releasing substituents.

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Section: Introductionmentioning

confidence: 93%

Fluorescence lifetimes of substituted indoles in solution and in free jets: evidence for intramolecular charge-transfer quenching

Arnold¹,

Tong²,

Sulkes³

1994

J. Phys. Chem.

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“…The short correlation time at 0.17 ns is associated with the local freedom of the tryptophanyl residues, as described in several studies of anisotropy decays of proteins. [35][36][37][38] The longer correlation time above 25 ns can be associated both to the overall rotation of the protein and to segmental motions of the side chains of AFEST. When the temperature is increased both the short and the long correlation times became shorter, suggesting a gradual increase of the overall flexibility of the protein structure.…”

Section: Fluorescence Analysismentioning

confidence: 98%

The thermophilic esterase fromArchaeoglobus fulgidus: Structure and conformational dynamics at high temperature

et al. 2000

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The esterase from the hyperthermophilic archaeon Archaeoglobus fulgidus is a monomeric protein with a molecular weight of about 35.5 kDa. The enzyme is barely active at room temperature, displaying the maximal enzyme activity at about 80 degrees C. We have investigated the effect of the temperature on the protein structure by Fourier-transform infrared spectroscopy. The data show that between 20 degrees C and 60 degrees C a small but significant decrease of the beta-sheet bands occurred, indicating a partial loss of beta-sheets. This finding may be surprising for a thermophilic protein and suggests the presence of a temperature-sensitive beta-sheet. The increase in temperature from 60 degrees C to 98 degrees C induced a decrease of alpha-helix and beta-sheet bands which, however, are still easily detected at 98 degrees C indicating that at this temperature some secondary structure elements of the protein remain intact. The conformational dynamics of the esterase were investigated by frequency-domain fluorometry and anisotropy decays. The fluorescence studies showed that the intrinsic tryptophanyl fluorescence of the protein was well represented by the three-exponential model, and that the temperature affected the protein conformational dynamics. Remarkably, the tryptophanyl fluorescence emission reveals that the indolic residues remained shielded from the solvent up to 80 degrees C, as shown from the emission spectra and by acrylamide quenching experiments. The relationship between enzyme activity and protein structure is discussed.

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“…The transition dipole moment of the 1 L b is approximately perpendicular to that of the 1 L a and its magnitude is significantly weaker [5]. However, unlike the 1 L a transition, 1 L b transition, particularly its spectral shape, is quite sensitive to methyl or methoxy substitution in the indole [16].…”

Section: The Absorption Spectra Of Trp In Various Solvents and Their mentioning

confidence: 99%

“…The 1 L b transition, in contrast to the 1 L a , is quite sensitive to the methyl or methoxy substitutions on the indole ring, particularly at positions 4, 6, and 7. This results in changes of the relative intensities of the vibronic transitions [5,16]. It is reasonable to expect similar effects, although much smaller in scale, for Trp in instances where its benzene ring interacts with other side chains.…”

Section: Introductionmentioning

confidence: 99%

Site-directed circular dichroism of proteins: 1Lb bands of Trp resolve position-specific features in tear lipocalin

Gasymov

Abduragimov

Glasgow

2008

Analytical Biochemistry

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The absorption spectra of N-acetyl-L-tryptophanamide in various solvents were resolved into the sums of the 1 L a and 1 L b components. The relative intensities of the 0-0 transitions of the 1 L b bands correlate linearly with the solvent polarity values . A novel strategy, which utilizes a set of the experimental 1 L b bands, was employed to resolve the near-UV CD spectra of tryptophanyl residues. Resolved spectral parameters from the single-tryptophan mutants of tear lipocalin (TL), F99W and Y87W, corroborate the fluorescence as well as structural data of TL. Analysis of the 1 L b bands of the Trp CD spectra in proteins is a valuable tool to obtain the local features. The "DMSOlike" 1 L b band of Trp CD spectra may be used as a "fingerprint" to identify the tryptophanyl side chains in situations where the benzene rings of Trp have van der Waals interactions with the side chains of its nearest neighbor. In addition, the signs and intensities of the components hold information about the side-chain conformations and dynamics in proteins. Combined with Trp mutagenesis, this method we call site-directed circular dichroism is broadly applicable to various proteins to obtain the position-specific data.

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Photophysics of indole derivatives: experimental resolution of L a and L b transitions and comparison with theory

Cited by 23 publications

References 16 publications

Fluorescence lifetimes of substituted indoles in solution and in free jets: evidence for intramolecular charge-transfer quenching

Fluorescence lifetimes of substituted indoles in solution and in free jets: evidence for intramolecular charge-transfer quenching

The thermophilic esterase fromArchaeoglobus fulgidus: Structure and conformational dynamics at high temperature

Site-directed circular dichroism of proteins: 1Lb bands of Trp resolve position-specific features in tear lipocalin

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