Origin of Fluorescence Lifetimes in Human Serum Albumin. Studies on Native and Denatured Protein

Abstract

Human serum albumin consists of a single polypeptide of 585 amino acid residues with 1 Trp residue. In the present work, we measured fluorescence lifetimes of the protein in both native and denatured states. The results indicate that Trp emission occurs with three lifetimes in both states. Lifetimes values and contribution to the global emission decay differ between the two states. Data are interpreted as the results of an emission occurring from three substructures of the tryptophan formed in the excited state. Two of these substructures are already present for the tryptophan free in solution. The third lifetime is the result of the interaction between the tryptophan residue and surrounding microenvironment. The populations of these substructures characterized by the pre-exponential parameters of the fluorescence lifetimes are dependent on the fluorophore microenvironment and on the global protein structure.

Interaction of Human Serum Albumin with Novel 3,9-Disubstituted Perylenes

“…2): one component that has sub-nanosecond to approximately 1.5 ns lifetime, a second component with ~3–4 ns decay and a longer component with lifetime >7 ns. These are within the typical range observed for HSA [1]. The three individual components do not substantially change with the type of perylene added and the average lifetime (Eq.…”

Interaction of fisetin with human serum albumin by fluorescence, circular dichroism spectroscopy and DFT calculations: binding parameters and conformational changes

“…The decays in Fig. 1 obtained for HSA and different fisetin-HSA mixtures at 298 K were fitted as triexponential functions and the lifetimes are included in Table 1; the values for HSA in the absence of the ligand are in good agreement with literature data [30]. The plot of t 0 /t vs. the fisetin concentration (inset in Fig.…”

Conformational alterations induced by novel green 16-E2-16 gemini surfactant in xanthine oxidase: Biophysical insights from tensiometry, spectroscopy, microscopy and molecular modeling

“…Longer the hydrophobic tail of the surfactant, stronger is the ability of micelle formation and higher will be the efficacy to bind to protein surface, hence larger K SV . Since Stern-Volmer constant, K SV , is the product of quenching rate constant, k q , and fluorescence lifetime of protein in absence of quencher, s o (value of s o for biomolecules is considered to be 10 À8 s [53]), therefore:…”