Implications of oxidovanadium (IV) binding to actin,
Ramos, S., Almeida R. M., Moura J. J., and Aureliano M.
, Eur J Inorg Chem, Volume 105, Issue 6, p.777, (2011)
Implications of oxidovanadium(IV) binding to actin,
Ramos, S., Almeida R. M., Moura J. J., and Aureliano M.
, J Inorg Biochem, Jun, Volume 105, Number 6, p.777-83, (2010)
AbstractOxidovanadium(IV), a cationic species (VO(2+)) of vanadium(IV), binds to several proteins, including actin. Upon titration with oxidovanadium(IV), approximately 100% quenching of the intrinsic fluorescence of monomeric actin purified from rabbit skeletal muscle (G-actin) was observed, with a V(50) of 131 muM, whereas for the polymerized form of actin (F-actin) 75% of quenching was obtained and a V(50) value of 320 muM. Stern-Volmer plots were used to estimate an oxidovanadium(IV)-actin dissociation constant, with K(d) of 8.2 muM and 64.1 muM VOSO(4), for G-actin and F-actin, respectively. These studies reveal the presence of a high affinity binding site for oxidovanadium(IV) in actin, producing local conformational changes near the tryptophans most accessible to water in the three-dimensional structure of actin. The actin conformational changes, also confirmed by (1)H NMR, are accompanied by changes in G-actin hydrophobic surface, but not in F-actin. The (1)H NMR spectra of G-actin treated with oxidovanadium(IV) clearly indicates changes in the resonances ascribed to methyl group and aliphatic regions as well as to aromatics and peptide-bond amide region. In parallel, it was verified that oxidovanadium(IV) prevents the G-actin polymerization into F-actin. In the 0-200 muM range, VOSO(4) inhibits 40% of the extent of polymerization with an IC(50) of 15.1 muM, whereas 500 muM VOSO(4) totally suppresses actin polymerization. The data strongly suggest that oxidovanadium(IV) binds to actin at specific binding sites preventing actin polymerization. By affecting actin structure and function, oxidovanadium(IV) might be responsible for many cellular effects described for vanadium.
Insights into the recognition and electron transfer steps in nitric oxide reductase from Marinobacter hydrocarbonoclasticus,
Ramos, S., Almeida R. M., Cordas C. M., Moura J. J. G., Pauleta S. R., and Moura I.
, J Inorg Biochem, Volume 177, p.402-411, (2017)
Isolation and characterization of a new Cu-Fe protein from Desulfovibrio aminophilus DSM12254,
Rivas, M. G., Mota C. S., Pauleta S. R., Carepo M. S., Folgosa F., Andrade S. L., Fauque G., Pereira A. S., Tavares P., Calvete J. J., Moura I., and Moura J. J.
, J Inorg Biochem, Oct, Volume 103, Number 10, p.1314-22, (2009)
AbstractThe isolation and characterization of a new metalloprotein containing Cu and Fe atoms is reported. The as-isolated Cu-Fe protein shows an UV-visible spectrum with absorption bands at 320 nm, 409 nm and 615 nm. Molecular mass of the native protein along with denaturating electrophoresis and mass spectrometry data show that this protein is a multimer consisting of 14+/-1 subunits of 15254.3+/-7.6 Da. Mossbauer spectroscopy data of the as-isolated Cu-Fe protein is consistent with the presence of [2Fe-2S](2+) centers. Data interpretation of the dithionite reduced protein suggest that the metallic cluster could be constituted by two ferromagnetically coupled [2Fe-2S](+) spin delocalized pairs. The biochemical properties of the Cu-Fe protein are similar to the recently reported molybdenum resistance associated protein from Desulfovibrio, D. alaskensis. Furthermore, a BLAST search from the DNA deduced amino acid sequence shows that the Cu-Fe protein has homology with proteins annotated as zinc resistance associated proteins from Desulfovibrio, D. alaskensis, D. vulgaris Hildenborough, D. piger ATCC 29098. These facts suggest a possible role of the Cu-Fe protein in metal tolerance.
Imine Ligands Based on Ferrocene: Synthesis, Structural and Mössbauer Characterization and Evaluation as Chromogenic and Electrochemical Sensors for Hg+2,
Rosa, V., Gaspari A., Folgosa F., Cordas C. M., Tavares P., Santos-Silva T., Barroso S., and Avilés T.
, New J Chem, Volume 42, p.3334-3343, (2018)