Please use this identifier to cite or link to this item: https://hdl.handle.net/10316/3868
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dc.contributor.authorSrinivasan, Chandra-
dc.contributor.authorToon, Jason-
dc.contributor.authorAmari, Louis-
dc.contributor.authorAbukhdeir, Abde M.-
dc.contributor.authorHamm, Heidi-
dc.contributor.authorGeraldes, Carlos F. G. C.-
dc.contributor.authorHo, Yee-Kin-
dc.contributor.authorFreitas, Duarte Mota de-
dc.date.accessioned2008-08-29T15:35:19Z-
dc.date.available2008-08-29T15:35:19Z-
dc.date.issued2004en_US
dc.identifier.citationJournal of Inorganic Biochemistry. 98:5 (2004) 691-701en_US
dc.identifier.urihttps://hdl.handle.net/10316/3868-
dc.description.abstractLi+ is the most effective drug used to treat bipolar disorder; however, its exact mechanism of action has yet to be elucidated. One hypothesis is that Li+ competes with Mg2+ for the Mg2+ binding sites on guanine-nucleotide binding proteins (G-proteins). Using 7Li T1 relaxation measurements and fluorescence spectroscopy with the Mg2+ fluorophore furaptra, we detected Li+/Mg2+ competition in three preparations: the purified G-protein transducin (Gt), stripped rod outer segment membranes (SROS), and SROS with purified Gt reattached (ROS-T). When purified ROS-T, SROS or transducin were titrated with Li+ in the presence of fixed amounts of Mg2+, the apparent Li+ binding constant decreased due to Li+/Mg2+ competition. Whereas for SROS the competition mechanism was monophasic, for Gt, the competition was biphasic, suggesting that in Gt, Li+/Mg2+ competition occurred with different affinities for Mg2+ in two types of Mg2+ binding sites. Moreover, as [Li+] increased, the fluorescence excitation spectra of both ROS-T and Gt were blue shifted, indicating an increase in free [Mg2+] compatible with Li+ displacement of Mg2+ from two low affinity Mg2+ binding sites of Gt. Gt release from ROS-T membrane was also inhibited by Li+ addition. In summary, we found evidence of Li+/Mg2+ competition in Gt-containing preparations.en_US
dc.description.urihttp://www.sciencedirect.com/science/article/B6TGG-4BJ2538-2/1/c5cc8bd5992b6629aba06705e0861119en_US
dc.format.mimetypeaplication/PDFen
dc.language.isoengeng
dc.rightsopenAccesseng
dc.subjectTransducinen_US
dc.subjectG-proteinsen_US
dc.subjectLithiumen_US
dc.subjectMagnesiumen_US
dc.subjectIonic competitionen_US
dc.titleCompetition between lithium and magnesium ions for the G-protein transducin in the guanosine 5'-diphosphate bound conformationen_US
dc.typearticleen_US
dc.identifier.doi10.1016/j.jinorgbio.2003.12.023-
uc.controloAutoridadeSim-
item.openairetypearticle-
item.languageiso639-1en-
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
item.cerifentitytypePublications-
item.grantfulltextopen-
item.fulltextCom Texto completo-
crisitem.author.researchunitCQC - Coimbra Chemistry Centre-
crisitem.author.parentresearchunitFaculty of Sciences and Technology-
crisitem.author.orcid0000-0002-0837-8329-
Appears in Collections:FCTUC Ciências da Vida - Artigos em Revistas Internacionais
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