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
More filters
Journal ArticleDOI
Coexistence of Native-Like and Non-Native Cytochrome c on Anionic Liposomes with Different Cardiolipin Content.
TL;DR: A hypothesis is proposed that describes the balance between facilitating and impeding forces controlling the peroxidase activity of cytochrome c in the inner membrane space of mitochondria in response to molecular crowding at low lipid concentrations and high occupancy of the liposome surface.
Journal ArticleDOI
pH reduction as a trigger for dissociation of herpes simplex virus type 1 scaffolds.
David A. McClelland,James Aitken,David Bhella,David McNab,Joyce Mitchell,Sharon M. Kelly,Nicholas C. Price,Frazer J. Rixon +7 more
TL;DR: The possibility that dissociation of the scaffold may be triggered by a reduction in pH brought about by the entry of the viral DNA into the capsid is suggested.
Journal ArticleDOI
Co-solvent mediated thermal stabilization of chondroitinase ABC I form Proteus vulgaris.
Mahdieh Nazari-Robati,Khosro Khajeh,Mahdi Aminian,Mehrnoosh Fathi-Roudsari,Abolfazl Golestani +4 more
TL;DR: The results support the idea that cABC I has stabilized in the presence of glycerol, sorbitol and trehalose, and the use of these cosolvents seems to be promising for improvement in shelf-life and clinical applications of this drug enzyme.
Journal ArticleDOI
Evidence for an acid-induced molten-globule state in interleukin-2; a fluorescence and circular dichroism study.
TL;DR: Analysis of fluorescence lifetimes and derivative emission spectra of the single tryptophan shows the existence of two distinct orientations for this side-chain, one of which is affected by a quenching group (the effect of which diminishes upon acidification) and another which is essentially unquenched.
Journal ArticleDOI
Protein degradation by peroxide catalyzed by chromium (III): role of coordinated ligand.
TL;DR: Spectroscopic and equilibrium dialysis studies show that the nature of the chromium (III) complex plays a major role in the biotoxicity of chromium, whereas the complexes in the presence of hydrogen peroxide have been found to bring about protein degradation, whereas Cr(en)(3+)(3) does not bring about any protein damage.
References
More filters
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.