Tyrosine fluorescence probing of conformational changes in tryptophan-lacking domain of albumins

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 174; pp. 223 - 229
• Main Authors: Zhdanova, N.G., Maksimov, E.G., Arutyunyan, A.M., Fadeev, V.V., Shirshin, E.A.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 05-03-2017
• Subjects: Albumin; Animals; Cattle; Circular Dichroism; Conformational changes; Fluorescence; Fluorescence lifetime; Fluorescence spectroscopy; Fluorescent Dyes - chemistry; Humans; Nephelometry and Turbidimetry; Oxazines - chemistry; Protein Domains; Serum Albumin - chemistry; Serum Albumin, Bovine - chemistry; Tryptophan - chemistry; Tyrosine - chemistry; Tyrosine fluorescence; Fluorescence spectroscopy; Albumin; Tyrosine fluorescence; Fluorescence lifetime; Conformational changes
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2016.11.038

We addressed the possibility of using tyrosine (Tyr) fluorescence for monitoring conformational changes of proteins which are undetectable via tryptophan (Trp) fluorescence. The model objects, human (HSA) and bovine (BSA) serum albumins, contain one and two Trp residues, respectively, while Tyr is more uniformly distributed over their structure. The results of the investigation of albumins interaction with ethanol using intrinsic Trp and Tyr steady-state and time-resolved picosecond fluorescence indicated the presence of an intermediate at 10% (v/v) of ethanol in solution, that was supported by the results of extrinsic fluorescence measurements with the Nile Red dye. Based on the comparison of HSA and BSA Trp and Tyr fluorescence, it was suggested that conformational changes at low ethanol concentration are located in the domain III of albumins, which lacks tryptophan residues. The sensitivity of Tyr fluorescence to domain III alterations was further verified by studying albumins interaction with GdnHCl.
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•Tyr fluorescence was used to monitor conformation of albumin with EtOH and GdnHCl.•Tyr-Trp fluorescence diagram reveals intermediates in protein folding.•Tyrosine fluorescence is sensitive to changes in domain III of albumin.