Untitled

Abstract

ASCUT-1 is a protein found in cuticlin, the insoluble residue of the cuticles of the nematode Ascaris lumbricoides. It contains the CUT-1-like domain which is shared by members of a novel family of components of extracellular matrices. The monomeric form of ASCUT-1 contains a single tryptophan residue. An understanding of the structure-function relationship of the protein under different chemical-physical conditions is of fundamental importance for an understanding of its structure and function in cuticles. In this paper we report the effect of the temperature and sodium dodecyl sulfate on the structural stability of this protein. The structure of the protein was studied in the temperature range 25-85°C in the absence and in the presence of sodium dodecyl sulfate by frequency-domain measurements of the intrinsic fluorescence intensity and anisotropy decays. The time-resolved fluorescence data in the absence of SDS indicated that the tryptophanyl emission decays were well described by a bimodal lifetime distribution, and that the temperature increases resulted in the sharpening and in the shortening of the tryptophanyl lifetime distribution. In the presence of SDS an unimodal fluorescence lifetime distribution as well as a marked decrease in the anisotropy decay values were observed.

Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures

“…The center of the lifetime distribution is indicative of the average microenvironments surrounding the SRB probe, while the distribution width is related to the range of environments. 42 The present study clearly shows that the fluorescence intensities, or, in other words, the quantum efficiencies, and radiative decay rates vary as a function of the metal-fluorophore distance. In general, the quantum yield and lifetime of a fluorophore are described as 9,10 (9) (10) where Γ and k nr are the radiative and nonradiative decay rates, respectively.…”

“…The full width at half-maxima (fwhm) of the Gaussian distributions on SiF surfaces are systematically increased as a function of the increasing distance between the metal and fluorophores. The center of the lifetime distribution is indicative of the average microenvironments surrounding the SRB probe, while the distribution width is related to the range of environments …”

Distance-Dependent Metal-Enhanced Intrinsic Fluorescence of Proteins Using Polyelectrolyte Layer-by-Layer Assembly and Aluminum Nanoparticles

“…The component with each individual τ value is given by I ( τ , t ) = α ( τ ) e − t / τ The total decay law is the sum of the individual decays weighed by the amplitudes I ( t ) = prefix∫ τ = 0 ∞ α false( τ false) e − t / τ d τ Considering a Gaussian distribution, the α­(τ) is given by α normalG ( τ ) = 1 α 2 π exp [ − false( 1 / 2 false) ( false( τ − τ̅ false) / σ ) 2 ] where τ̅ is the central value of the distribution and σ is the standard deviation of the Gaussian. For a Gaussian distribution, the full width at half-maximum is given by 2.354σ …”

Uric acid determination using uricase and the autotransducer molecular absorption properties of peroxidase

“…from the intrinsic composition of the protein, such as the general UV fluorescence (due to aminoacids, mainly tryptophan [2]) or the specific visible fluorescence (FAD-containing proteins or the green fluorescence protein [3]), or after chemical or genetic modification or both [4][5][6], the periplasmic binding proteins being the most popular example [7]. Finally, molecular absorption properties are now being exploited for analytical uses, the most important example being the metalloproteins.…”