Comparison of Experimental and Broken Symmetry Density Functional Theory Calculated Electron Paramagnetic Resonance Parameters for the Manganese Catalase Active Site in the Superoxidized MnIII/MnIV State
journal contributionposted on 22.02.2018, 00:00 by Nathan J. Beal, Thomas A. Corry, Patrick J. O’Malley
Broken symmetry density functional theory has been used to calculate g-tensor, 55Mn, 14N, and 17O hyperfine couplings for active site models of superoxidized MnIII/MnIV manganese catalase both in its native and azide-inhibited form. While a good agreement is found between the calculated and experimental g-tensor and 55Mn hyperfine couplings for all models, the active site geometry and Mn ion oxidation state can only be readily distinguished based on a comparison of the calculated and experimental 14N azide and 17O HFCs. This comparison shows that only models containing a Jahn–Teller distorted 5-coordinate (MnIII)2 site and a 6-coordinate (MnIV)1 site can satisfactorily reproduce the experimental 14N and 17O hyperfine couplings.