Studies on the interaction between chromium(VI) and human serum albumin: Spectroscopic approach

The interaction between Cr2O72− and human serum albumin (HSA) was investigated using fluorescence, UV/vis, FT-IR, CD spectroscopy, and molecular modeling method. The experimental results showed that the fluorescence quenching of HSA by Cr2O72− is a result of the formation of HSA–chromium(VI) complex; static quenching was confirmed to result in the fluorescence quenching. The corresponding thermodynamic parameters showed that the process of binding Cr2O72− on HSA was a spontaneous molecular interaction procedure. Ionic, H-bonds and van der Waals interactions play a major role in stabilizing the complex. The Cr2O72− altered the environments of Trp and Tyr residues in HSA.

The fluorescence intensity of HSA decreased regularly and the maximum of emission wavelength shifted from 345 to 337 nm with the increasing Cr2O72− concentration, indicating that the formation of HSA–Cr2O72− complex. Ionic, H-bonds and van der Waals interactions play a major role in stabilizing the complex. The Cr2O72− altered the environments of Trp and Tyr residues in HSA. This study is expected to provide important insight into the interactions of the physiologically important proteins with toxic metal ion.Figure optionsDownload as PowerPoint slideHighlights
► The interaction between Cr2O72− and HSA is investigated by multi-spectral methods.
► There are about four binding sites for Cr2O72− in HSA.
► Ionic, H-bonds and van der Waals interactions stabilize the HSA–Cr2O72− complex.
► The Cr2O72− alters the environments of Trp and Tyr residues in HSA.
► The three-dimensional fluorescence spectra of HSA–Cr2O72− system is showed in paper.