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Metal ion dependent adhesion sites in integrins: a combined DFT and QMC study on Mn2+.
Sebastian, Eider San; Matxain, Jon M; Eriksson, Leif A; Stote, Roland H; Dejaegere, Annick; Cossio, Fernando P; Lopez, Xabier.
Affiliation
  • Sebastian ES; Kimika Fakultatea, Euskal Herriko Unibertsitatea, P.K. 1072, 20080 Donostia, Spain.
J Phys Chem B ; 111(30): 9099-103, 2007 Aug 02.
Article in En | MEDLINE | ID: mdl-17608410
The theoretical study of relative energies of different spin states of Mn2+ has been carried out for the isolated cation and for structures in which the cation is coordinated to ligands that represent the first coordination shell in a protein environment that contains a metal ion dependent adhesion site (MIDAS, found in the ligand binding domain of protein LFA-1). The calculations determine whether the ligand field generated by a prototype protein environment affects the relative energies between high, intermediate, and low spin states. Geometry optimizations and vibrational frequency calculations were carried out at the B3LYP/SKBJ+* level of theory. Single point calculations were performed at the B3LYP/6-311++G(2df,2p) and diffusion monte carlo (DMC) levels for the refinement of the electronic energies. These calculations reveal important differences in the relative energies between high/low spin complexes obtained by B3LYP and DMC and show that although both DFT and DMC show similar trends, a higher level method such as DMC is necessary for a quantitative description of the interactions between Mn2+ and its natural ligands. (G)s of acetate-type ligand binding reactions were calculated that show that the higher the spin of the manganese complex, the lower the affinity for the ligand.
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Collection: 01-internacional Database: MEDLINE Main subject: Integrins / Manganese / Metalloproteins Language: En Journal: J Phys Chem B Journal subject: QUIMICA Year: 2007 Document type: Article Affiliation country: Country of publication:
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Collection: 01-internacional Database: MEDLINE Main subject: Integrins / Manganese / Metalloproteins Language: En Journal: J Phys Chem B Journal subject: QUIMICA Year: 2007 Document type: Article Affiliation country: Country of publication: