Studies on the interactions between human serum albumin and trans-indazolium (bisindazole) tetrachlororuthenate(III)

The interactions between HInd[RuInd(2)Cl(4)] and human serum albumin have b een investigated through UV-Vis, circular dichroism (CD), fluorescence spec troscopy and the inductively coupled plasma-atomic emission spectroscopy (I CP(AES)) method. Binding of Ru(III)-indazole species to albumin has strong impact on protein structure and it influences considerably albumin binding of other molecules like warfarin, heme or metal ions. The metal complex-hum an serum albumin (HAS) interactions cause conformational changes with loss of helical stability of the protein and local perturbation in the domain II A binding pocket. The relative fluorescence intensity of the ruthenium-boun d HSA decreased, suggesting that perturbation around the Trp 214 residue to ok place. This was confirmed by the destabilization of the warfarin-binding site, which includes Trp 214, observed in the metal-bound HSA. (C) 2000 El sevier Science Inc. All rights reserved.