<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ramos, S.</style></author><author><style face="normal" font="default" size="100%">Almeida, R. M.</style></author><author><style face="normal" font="default" size="100%">Moura, J. J.</style></author><author><style face="normal" font="default" size="100%">Aureliano, M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Implications of oxidovanadium(IV) binding to actin</style></title><secondary-title><style face="normal" font="default" size="100%">J Inorg Biochem</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Actins/*chemistry/metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Adenosine Triphosphate/chemistry/metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Binding Sites</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrophobic and Hydrophilic Interactions</style></keyword><keyword><style  face="normal" font="default" size="100%">Kinetics</style></keyword><keyword><style  face="normal" font="default" size="100%">Magnetic Resonance Spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">Muscle, Skeletal/metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymerization</style></keyword><keyword><style  face="normal" font="default" size="100%">Rabbits</style></keyword><keyword><style  face="normal" font="default" size="100%">Vanadates/*chemistry/*metabolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Vanadium/*chemistry/metabolism</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">Jun</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&amp;db=PubMed&amp;dopt=Citation&amp;list_uids=21497575 </style></url></web-urls></urls><number><style face="normal" font="default" size="100%">6</style></number><volume><style face="normal" font="default" size="100%">105</style></volume><pages><style face="normal" font="default" size="100%">777-83</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Oxidovanadium(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.&lt;/p&gt;
</style></abstract><accession-num><style face="normal" font="default" size="100%">21497575</style></accession-num><notes><style face="normal" font="default" size="100%">&lt;p&gt;1873-3344 (Electronic)0162-0134 (Linking)Journal ArticleResearch Support, Non-U.S. Gov't&lt;/p&gt;
</style></notes><auth-address><style face="normal" font="default" size="100%">REQUIMTE/CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, Caparica, Portugal. s.ramos@dq.fct.unl.pt</style></auth-address></record></records></xml>