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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Probing a family GH11 endo-β-1,4-xylanase inhibition mechanism by phenolic compounds: Role of functional phenolic groups
Imen Boukari,Imen Boukari,Michael J. O’Donohue,Michael J. O’Donohue,Michael J. O’Donohue,Caroline Rémond,Caroline Rémond,Brigitte Chabbert,Brigitte Chabbert +8 more
TL;DR: Results indicated that the inhibitory effects of phenolic compounds on Tx-Xyl activity are most likely brought about by conformational alterations of the enzyme protein inducing steric inactivation.
Journal ArticleDOI
Peroxynitrite-induced oxidation and its effects on isolated proteasomal systems.
TL;DR: It is indicated that peroxynitrite caused a mild modification of the XYZ complex, leading to activation of its catalytic activities, and differently, the LMP proteasome showed a more significant conformational change resulting in the inhibition of the proteolytic functions.
Journal ArticleDOI
Binding of chondroitin 4-sulfate to cathepsin S regulates its enzymatic activity.
Juliette Sage,Florian Mallevre,Fabien Barbarin-Costes,Sergey A. Samsonov,Jan-Philip Gehrcke,Maria Teresa Pisabarro,Eric Perrier,Sylvianne Schnebert,Andre Roget,Thierry Livache,Carine Nizard,Gilles Lalmanach,Fabien Lecaille +12 more
TL;DR: A novel glycosaminoglycan-mediated mechanism of catS inhibition is described and it is suggested that C4-S may modulate the collagenase activity ofCatS in vivo.
Journal ArticleDOI
Specific amino acid substitutions determine the differential contribution of the N- and C-terminal domains of insulin-like growth factor (IGF)-binding protein-5 in binding IGF-I
John H. Shand,James Beattie,Hyuk Song,Kirsten Phillips,Sharon M. Kelly,David J. Flint,Gordon J. Allan +6 more
TL;DR: It is reported that mutagenesis of both amino acids simultaneously (C-Term mutant) results in a cumulative effect and an even greater reduction in IGF-I binding: 30-fold measured by solution phase IGF binding assay and 10-fold by biosensor analysis.
Journal ArticleDOI
Molybdate binding by ModA, the periplasmic component of the Escherichia coli mod molybdate transport system.
TL;DR: ModA, the periplasmic-binding protein of the Escherichia coli mod transport system was overexpressed and purified and showed an intrinsic fluorescence emission spectrum attributable to its three tryptophanyl residues.
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.