Journal ArticleDOI
Exposure of tryptophanyl residues in proteins. Quantitative determination by fluorescence quenching studies.
TLDR
The value of this probing technique lies in its ability to sense not only the steady-state exposure of a residue in a protein, but also its dynamic exposure.Abstract:
Acrylamide is an efficient quencher of tryptophanyl fluorescence which we report to be very discriminating in sensing the degree of exposure of this residue in proteins. The quenching reaction involves physical contact between the quencher and an excited indole ring, and can be kinetically described in terms of a collisional and a static component. The rate constant for the collisional component is a kinetic measure of the exposure of a residue in a protein, and values ranging from 4 X 10(9) M-1 S-1 for the fully exposed tryptophan in the polypeptide, adrenocorticotropin, to less than 5 X 10(8) M-1 S-1 for the buried residue in azurin have been found. Static quenching is readily detected in proteins that are denatured, or contain only a single fluorophor. Quenching patterns for most multi-tryptophan containing proteins are difficult to analyze precisely, but qualitative information can, nevertheless, be extracted. Applications of this probing technique for monitoring protein conformational changes, such as the acid-induced expansion of human serum albumin, and inhibitor binding to enzymes, are presented. The value of this method lies in its ability to sense not only the steady-state exposure of a residue in a protein, but also its dynamic exposure.read more
Citations
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pH-induced transitions in cholera toxin conformation: a fluorescence study.
TL;DR: The weak hydrophobic nature of CT A is reflected by the negative modulatory action of anionic phospholipids and deoxycholate on its mono-ADP-ribosyltransferase activity and the ability of the former to decrease its intrinsic fluorescence intensity in a salt-resistant way.
Journal ArticleDOI
Temperature dependent 2nd derivative absorbance spectroscopy of aromatic amino acids as a probe of protein dynamics.
TL;DR: It is shown that plots of the temperature dependent 2nd derivative peak positions of aromatic residues have measurable slopes before protein unfolding and that these slopes are sensitive to the dielectric properties of the surrounding microenvironment and can therefore be used as qualitative probes of protein dynamics.
Journal ArticleDOI
Reversible unfolding of the gelatin-binding domain of fibronectin: structural stability in relation to function.
TL;DR: Solvent perturbation, fluorescence quenching, and chemical modification experiments indicate that about half of the 8 tryptophans, one-third of the 21 tyrosines, and all of the 9 lysine residues are solvent-exposed in the native protein and that 1 or more of the latter are directly involved in binding to gelatin, most likely through a hydrogen-bonding mechanism.
Journal ArticleDOI
Intermolecular interactions of gramicidin A' transmembrane channels incorporated into lysophosphatidylcholine lipid systems.
TL;DR: The quantum yield for the incorporated state, when gramicidin A' is within the lipid matrix, is very low and indicates the occurrence of intermolecular Trp-Trp interactions.
Journal ArticleDOI
Luminescence studies with trp repressor and its single-tryptophan mutants
Maurice R. Eftink,Glen D. Ramsay,Laura E. Burns,August H. Maki,Craig J. Mann,C. R. Matthews,Camillo A. Ghiron +6 more
TL;DR: In this article, the luminescence contributions of the two intrinsic tryptophan residues in the subunits of trp aporepressor from Escherichia coli were confirmed by using the single-tryptophan mutants W19F and W99F.
References
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Journal ArticleDOI
The interpretation of protein structures: estimation of static accessibility.
B. Lee,Frederic M. Richards +1 more
TL;DR: The accessibility of atoms in the twenty common amino acids in model tripeptides of the type Ala-X-Ala are given for defined conformation and the larger non-polar amino acids tend to be more “buried” in the native form of all three proteins.
Journal ArticleDOI
Removal of Fatty Acids from Serum Albumin by Charcoal Treatment
TL;DR: Fluorescence spectra of human serum albumin samples indicated that impurities are sometimes present which can be removed by charcoal at neutral pH, and acid-charcoal treatment is a much more rapid method of removing lipid impurities than other methods previously described.
Journal ArticleDOI
Solute perturbation of protein fluorescence. The quenching of the tryptophyl fluorescence of model compounds and of lysozyme by iodide ion.
TL;DR: The results of the model compound study provide evidence for a mechanism that follows the classical Stern-Volmer law (1919), predominantly involving collisional quenching, and illustrate the importance of local charge and solvent viscosity.