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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Journal ArticleDOI
Glycine-Rich Loop of Mitochondrial Processing Peptidase α-Subunit Is Responsible for Substrate Recognition by a Mechanism Analogous to Mitochondrial Receptor Tom20
Klára Dvoráková-Holá,Anna Matušková,Martin Kubala,Michal Otyepka,Tomáš Kučera,Jaroslav Vecer,Petr Herman,Natalya Parkhomenko,Eva Kutejová,Eva Kutejová,Jiri Janata +10 more
TL;DR: It is concluded that the GRL of the MPP alpha-subunit is the crucial evolutional outcome of the presequence recognition by MPP and represents a functional parallel with Tom20 import receptor.
Journal ArticleDOI
Circular dichroic and fluoropolarimetric studies on tryptophyl residues in acid‐induced isomerization of bovine plasma albumin*
TL;DR: The acid-induced isomerization (the N-F transition) and expansion of bovine plasma albumin were studied by measuring circular dichroic spectra and fluorescence polarization of tryptophyl residues and increases in the magnitude of ellipticities observed in the initial part of the N- F transition exactly correlated with the increase of rotational relaxation time of tryPTophyl side chains obtained by fluorescence polarized measurement.
Journal ArticleDOI
The association of acrylamide with proteins. The interpretation of fluorescence quenching experiments.
TL;DR: Equilibrium dialysis experiments performed for the latter system verify that acrylamide associates with proteins, and according to both partition and binding processes.
Journal ArticleDOI
Fluorescence studies of exchangeable apolipoprotein-lipid interactions. Superficial association of apolipophorin III with lipoprotein surfaces.
TL;DR: Intrinsic fluorescence of the single tyrosine in apoLp-III was exploited to monitor the location of helix 5 in model disc complexes and support the concept that interaction with spherical lipoprotein particles results in superficial contact with the monolayer surface, providing a basis for its reversible binding ability.
Journal ArticleDOI
Acrylamide and molecular oxygen fluorescence quenching as a probe of solvent-accessibility of aromatic fluorophores complexed with DNA in relation to their conformations: coronene-DNA and other complexes.
TL;DR: It is concluded that O, is useful as a qualitative probe of the type of binding and solvent exposure of fluorophore‐DNA complexes, while acrylamide appears to be of limited utility.
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.