title: An assessment of pure, hybrid, meta, and hybrid-meta GGA density functional theory methods for open-shell systems: the case of the nonheme iron enzyme 8R-LOX.
abstract: The performance of a range density functional theory functionals combined in a quantum mechanical (QM)/molecular mechanical (MM) approach was investigated in their ability to reliably provide geometries, electronic distributions, and relative energies of a multicentered open-shell mechanistic intermediate in the mechanism 8R-Lipoxygenase. With the use of large QM/MM active site chemical models, the smallest average differences in geometries between the catalytically relevant quartet and sextet complexes were obtained with the B3LYP(*) functional. Moreover, in the case of the relative energies between (4) II and (6) II, the use of the B3LYP(*) functional provided a difference of 0.0 kcal mol(-1). However, B3LYP(±) and B3LYP also predicted differences in energies of less than 1 kcal mol(-1). In the case of describing the electronic distribution (i.e., spin density), the B3LYP(*), B3LYP, or M06-L functionals appeared to be the most suitable. Overall, the results obtained suggest that for systems with multiple centers having unpaired electrons, the B3LYP(*) appears most well rounded to provide reliable geometries, electronic structures, and relative energies.
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada.
authors.forename: Eric A C
authors.initials: EA
authors.lastname: Bushnell
authors.forename: James W
authors.initials: JW
authors.lastname: Gauld
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000737:chemistry / Q000201:enzymology*; D020134:Catalytic Domain; D004583:Electrons; D008084:Lipoxygenase / Q000737:chemistry* / Q000378:metabolism; D062105:Molecular Docking Simulation; D011789:Quantum Theory
chemical_list: D008084:Lipoxygenase