Metal Ion Dependent Adhesion Sites in Integrins: a Combined Dft and Qmc Study on Mn2+.
From: Kimika Fakultatea, Euskal Herriko Unibertsitatea, P.K. 1072, 20080 Donostia, Spain.
The journal of physical chemistry. B
- Publish Date: Aug 2007
- ISSN: 1520-6106
- Volume: 111
- Issue: 30
- Pages: 9099-103
- Medium: Print
- Language: English
- Citation (JAMA): Sebastian Eider San, Matxain Jon M, Eriksson Leif A, et al. Metal Ion Dependent Adhesion Sites in Integrins: a Combined Dft and Qmc Study on Mn2+.. Aug 2007;111:9099-103
Abstract
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.
Mesh Headings (Keywords): Algorithms, Binding Sites, Integrins, Ligands, Manganese, Metalloproteins, Protein Binding, Quantum Theory, Thermodynamics
Check for Full Text / PubMed Unique Identifier (PMID): 17608410
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