A Comparison between Vanadyl, Vanadate, and Decavanadate Effects in Actin Structure and Function: Combination of Several Spectroscopic Studies. Issue 5 (11th July 2012)

• Record Type: Journal Article
• Authors: Ramos Ramos, S. S.; Moura Moura, J. J. G. J. J. G.; Aureliano Aureliano, M. M.
• Is Part Of: Spectroscopy. Volume 27:Issue 5/6(2012)
• Page Start: 355
• Page End: 359
• Publication Date: 2012-07-11
• Subjects: Actin -- vanadyl -- decavanadate -- vanadate -- cysteine oxidation -- intrinsic fluorescence -- ANSA probe -- NMR -- EPR
• DOI: 10.1155/2012/532904
• Languages: English
• ISSNs: 0712-4813

Abstract

Abstract : The studies about the interaction of actin with vanadium are seldom. In the present paper the effects of vanadyl, vanadate, and decavanadate in the actin structure and function were compared. Decavanadate clearly interacts with actin, as shown byV 51 -NMR spectroscopy. Decavanadate interaction with actin induces protein cysteine oxidation and vanadyl formation, being both prevented by the natural ligand of the protein, ATP. Monomeric actin (G-actin) titration with vanadyl, as analysed by EPR spectroscopy, indicates a 1 : 1 binding stoichiometry and ak d of 7.5 μ M. Both decavanadate and vanadyl inhibited G-actin polymerization into actin filaments (F-actin), with aIC 50 of 68 and 300 μ M, respectively, as analysed by light-scattering assays. However, only vanadyl induces G-actin intrinsic fluorescence quenching, which suggests the presence of vanadyl high-affinity actin-binding sites. Decavanadate increases (2.6-fold) actin hydrophobic surface, evaluated using the ANSA probe, whereas vanadyl decreases it (15%). Finally, both vanadium species increasedε -ATP exchange rate (k = 6.5 × 10 − 3 and4.47 × 10 − 3 s − 1 for decavanadate and vanadyl, resp.). Putting it all together, it is suggested that actin, which is involved in many cellular processes, might be a potential target not only for decavanadate but above all for vanadyl.