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
The characterization of plasma membrane Ca2+-ATPase in rich sphingomyelin-cholesterol domains
TL;DR: It is suggested that the specific domains containing high SPM–CHOL concentration are not a favorable place for PMCA activity, and a possible explanation about PMCA molecules concentrated in caveolae/rafts was discussed.
Journal ArticleDOI
The effects of pH on the interaction of anthrax toxin lethal and edema factors with phospholipid vesicles.
TL;DR: The results suggest that LF and EF may be actively involved in the process of toxin translocation, as low pH-induced membrane insertion by both proteins was accompanied by only a minimal change in conformation.
Journal ArticleDOI
Synthesis, spectral characterization and biological evaluation of some copper(II) complexes containing 4-oxo-4H-chromene-3-carbaldehyde-4(N)-substituted thiosemicarbazones
TL;DR: The new water soluble chromone appended copper(II) complexes have shown significant growth inhibitory activity against selected types of bacteria and fungi and overcome cisplatin resistance in the MCF-7 and A549 cell lines.
Journal ArticleDOI
The accessibility of the active site and conformation states of the beta 2 subunit of tryptophan synthase studied by fluorescence quenching.
TL;DR: The effect of iodide on the fluorescence properties of holo alpha 2beta 2 complex allows us to estimate an upper limit for the dissociation constant for the alpha 2 beta 2 complex of 10(-8) M, in the absence of iodides.
Journal ArticleDOI
Structural Plasticity in Influenza Virus Protein NS2 (NEP)
Barbara S. Lommer,Ming Luo +1 more
TL;DR: The results indicate that isolated NS2 exists as a monomer in solution, and adopts a compact, but very flexible conformation, which shows characteristics of the molten globule state under near physiological conditions.
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.