Unexpected in crystallo reactivity of the potential drug bis(maltolato)oxidovanadium(iv) with lysozyme

The high-resolution X-ray structure of the adduct formed upon the reaction of hen egg white lysozyme (HEWL) with the potential drug BMOV (bis(maltolato)oxidovanadium(iv) or [VIVO(malt)2], where malt = maltolato) from crystals grown in 1.1 M NaCl and 0.1 M sodium acetate at pH 4.0 reveals an unexpected reaction product, where the V compound is transformed, the maltolate ring is broken and a significant modification of the N-terminal lysine side chain is observed. The results, also supported by gel electrophoresis and mass spectrometry data, show an unusual reactivity of BMOV with HEWL in the solid state, prompting further research on the reactivity of vanadium compounds with proteins which could depend on the specific experimental conditions.