Abstract
The interaction properties of monensin/clopidol with bovine/human serum albumin (BSA/HSA) were determined via multispectral together with molecular modeling techniques in the report. Fluorescence quenching spectra at different temperatures and fluorescence lifetime determination demonstrated that the fluorescence quenching belonged to a static quenching type. In the case of monensin-BSA, clopidol-BSA, monensin-HSA and clopidol-HSA, the binding constants Ka (291 K) were 5.42 × 104, 4.96 × 104, 3.22 × 104 and 2.99 × 104 M−1, respectively; the binding distances r0 were 1.88, 2.53, 2.19 and 2.02 nm, respectively. Monensin and clopidol bound strongly with BSA/HSA with binding free energies equal to −26.37/−25.11 and −26.11/−24.93 kJ mol−1, respectively. The spontaneous binding process was dominated by hydrogen bonds and van der Waals forces as reflected in thermodynamic parameters analyses. Synchronous, CD, FTIR and UV-vis spectra assays confirmed that serum albumins conformations were altered. Using competitive experiment, monensin/clopidol was observed to bind at site I of serum albumins, which were reconfirmed by the results of molecular modeling.
Communicated by Ramaswamy H. Sarma
![](/cms/asset/97be18e9-7ab3-4643-9316-5b5868cad14f/tbsd_a_1886173_uf0001_c.jpg)
Disclosure statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.