By using titin as a model system, we have demonstrated that fluorescence quenching can be used to study protein folding at the single molecule level. The unfolded titin molecules with multiple dye molecules attached are able to fold to the native state. In the native folded state, the fluorescence from dye molecules is quenched due to the close proximity between the dye molecules. Unfolding of ...

Quinone-based fluorophores and enhanced native fluorescence techniques were applied for a fast quantitative analysis of gemifloxacin mesylate (GEM) and linezolid (LIN) in pharmaceutical formulations. For this purpose, three sensitive, accurate and precise spectrofluorimetric methods were developed. GEM, as an n-electron donor, reacts with 7,7,8,8-tetracyanoquinodimethane (method A) and 2,5-dich...

The formation of the intermediate state of papain was induced by n-alkyl sulfates including sodium octyl sulfate, SOS; sodium decyl sulfate, SDeS; and sodium dodecyl sulfate, SDS at different concentrations. A systematic investigation of n-alkyl sulfates induced conformational alteration in molten globule state under an acidic condition and the native state of papain was examined by tryptophan ...

Conformational analysis of champedak galactose-binding (CGB) lectin under different urea concentrations was studied in phosphate-buffered saline (pH 7.2) using far-ultraviolet circular dichroism (far-UV CD), tryptophan (Trp) fluorescence and ANS fluorescence. In all cases, CGB lectin displayed a two-step, three-state transition. The first transition (from the native state to the intermediate st...

We present the detection of single beta-galactosidase molecules from Escherichia coli (Ecbeta Gal) using deep UV laser-based fluorescence lifetime microscopy. The native fluorescence from intrinsic tryptophan emission has been observed after one-photon excitation at 266 nm. Applying the time-resolved single-photon counting method, we investigated the fluorescence lifetime distribution and the b...

The exopolysaccharide secreted by Lacticaseibacillus paracasei subsp. SS-01 strain (LP-EPS) is isolated and purified from yogurt. It a polysaccharide with branched multi-stranded structure, which exists in smooth rod-like or cloud-like state, possesses good thermal stability molecular weight of 49.68 kDa (±4.436%). LP-EPS shows high antioxidant capacity, anti-inflammatory anti-sensitizing activ...