Abstact

Understanding the impact of oxidative modification on protein structure and functions is essential for developing therapeutic strategies to combat macromolecular damage and cell death. However, selectively inducing oxidative modifications in proteins under physiological conditions remains challenging. Herein we demonstrate that [V6O13{(OCH2)3CCH2OH}2]2- (V6-OH) hybrid metal-oxo cluster can be used for selective protein oxidative cleavage and modifications. We present the first example of a protein-bound hybrid vanadate cluster, where its interactions with protein surfaces and the redox activity of vanadium enable selective oxidative modifications. Single Crystal X-ray Diffraction (SC-XRD) of the V6-OH and hen egg white lysozyme (HEWL) complex revealed that the binding is dictated both by the inorganic core and the organic ligands attached to it. Selective oxidation or cleavage of HEWL occurs under physiological conditions by producing reactive oxygen species (ROS) in presence of ascorbate (Asc) as a reducing agent. The outcome of the oxidative reaction can be tuned by varying the concentration of V6-OH to result either in selective oxidation of the amino acid side chains or peptide bond cleavage. LC-MS and crystallography revealed that oxidative modifications were mainly concentrated near the cluster binding sites, providing spatial control of ROS production. This study advances our understanding of vanadium's role in biological systems and demonstrates the potential of hybrid metal-oxo clusters in protein modification.