Study of fluorescence interaction and conformational changes of bovine serum albumin with histamine H1-receptor-drug epinastine hydrochloride by spectroscopic and time-resolved fluorescence methods

Biopolymers ◽  
2015 ◽  
Vol 103 (11) ◽  
pp. 646-657 ◽  
Author(s):  
Girish G. Ariga ◽  
Praveen N. Naik ◽  
Sharanappa T. Nandibewoor ◽  
Shivamurti A. Chimatadar
2016 ◽  
Vol 70 (10) ◽  
pp. 1733-1738 ◽  
Author(s):  
Lei Li ◽  
Hua Yi ◽  
Menghui Jia ◽  
Mengfang Chang ◽  
Zhongneng Zhou ◽  
...  

In this paper, we report a pyridinium salt “turn-on” fluorescent probe, 4-[2-(4-Dimethylamino-phenyl)-vinyl]-1-methylpyridinium iodide (p-DASPMI), and applied its time-resolved fluorescence (TRF) to monitor the protein conformational changes. Both the fluorescence lifetime and quantum yield (QY) of p-DASPMI were increased about two orders of magnitude after binding to the protein bovine serum albumin (BSA). The free p-DASPMI in solution presents an ultrashort fluorescence lifetime (12.4 ps), thus it does not interfere the detection of bound p-DASPMI which has nanosecond fluorescence lifetime. Decay-associated spectra (DAS) show that p-DASPMI molecules bind to subdomains IIA and IIIA of BSA. The TRF decay profiles of p-DASPMI can be described by the multi-exponential decay function ([Formula: see text]), and the obtained parameters, such as lifetimes ([Formula: see text]), fractional amplitudes ([Formula: see text]), and fractional intensities ([Formula: see text]), may be used to deduce the conformational changes of BSA. The pH and Cu2+ induced conformational changes of BSA were investigated through the TRF of p-DASPMI. The results show that the p-DASPMI is a candidate fluorescent probe in studying the conformational changes of proteins through TRF spectroscopy and microscopy in the visible range.


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