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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A Circular Dichroism and Fluorescence Spectrometric Assessment of Effects of Selected Chemical Denaturants on Soybean (Glycine max L.) Storage Proteins Glycinin (11S) and β-Conglycinin (7S)
TL;DR: Soybean glycinin and β-conglycinin were subjected to select chemical treatments at various concentrations and resulting changes in protein structures were investigated by circular dichroism and fluorescence spectrometry, indicating that urea ≥3 M caused significant unfolding of 11S, but not that of 7S.
Journal Article
Quenching of Tryptophan Fluorescence in Various Proteins by a Series of Small Nickel Complexes
Heather F. Crouse,Julianne Potoma,Farhat Nejrabi,Deanna L. Snyder,Balwant S. Chohan,Swarna Basu +5 more
TL;DR: Only small neutral complexes with hydrophobic ligands effectively quenched protein fluorescence via static quenching, with association constants ranging from 10(2) M−1 (free Trp) to 10(10) M(-1) (lysozyme), indicating a spontaneous and thermodynamically favorable interaction.
Journal ArticleDOI
Differential interactions and structural stability of chitosan oligomers with human serum albumin and α-1-glycoprotein.
TL;DR: Thermodynamic and molecular docking analysis and circular dichroism studies suggest that HSA might serve as a carrier in delivering chitooligomers to target tissues than AGP which has pharmacological importance.
Journal ArticleDOI
Purification and characterization of papaya glutamine cyclotransferase, a plant enzyme highly resistant to chemical, acid and thermal denaturation
Samira Zerhouni,Amina Amrani,Michelle Nijs,Nicole Smolders,Mohamed Azarkan,Jean Vincentelli,Yvan Looze +6 more
TL;DR: Papaya glutamine cyclotransferase (PQC), present in the laticiferous cells of the tropical species Carica papaya, was purified near to homogeneity and preliminary experiments show that papaya QC is exceptionally resistant to chemical, acid, acid and thermal denaturation.
Journal ArticleDOI
Structural changes accompanying chloroform-induced contraction of the filamentous phage fd.
Linda M. Roberts,A.K. Dunker +1 more
TL;DR: Data support previous suggestions that chloroform-induced filamentous phage contraction may provide information about phage penetration and assembly in vivo.
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.