Model Systems of Heme Proteins.
R. E. Berry, F. Yang, T. K. Shokhireva, A. Amoia, S. A. Garrett, A. M. Goren, S. R. Korte, H. Zhang, A. Weichsel, W. R. Montfort, F. A. Walker. Dimerization of Nitrophorin 4 at Low pH: Comparison to the K1A Mutant of Nitrophorin 1, Biochemistry 2015, 54, 208-220.
R. E. Berry, D. Muthu, T. K. Shokhireva, S. A. Garrett, A. M. Goren, H. Zhang, F. A. Walker. NMR Investigations of Nitrophorin 2 Belt Side Chain Effects on Heme Orientation and Seating of Native N-Terminus NP2 and NP2(D1A), J. Biol. Inorg. Chem. 2014, 19, 577-593.
T. K. Shokhireva, F. A. Walker. Assignment of the 1H NMR Resonances of Protein Residues in Close Proximity to the Heme of the Nitrophorins: Similarities and Differences among the Four Proteins from the Saliva of the Adult Blood-Sucking Insect, Rhodinus prolixus, J. Biol. Inorg. Chem. 2012, 17, 911-926; 1303.
R. E. Berry, D. Muthu, S. A. Garrett, T. K. Shokhireva, H. Zhang, F. A. Walker. Native N-Terminus Nitrophorin 2 from the Kissing Bug: Similarities to and Differences from NP2(D1A), Chem. Biodiv. 2012, 9, 1739-1755.
T. K. Shokhireva, R. E. Berry, H. Zhang, F. A. Walker. NMR Studies of Nitrophorin Distal Pocket Side Chain Effects on the Heme Orientation and Seating of NP2 as Compared to NP1, J. Inorg. Biochem. 2011, 105, 1238-1257.
F. Yang, M. Knipp, R. E. Berry, T. K. Shokhireva, H. Zhang, F. A. Walker. 1H and 13C NMR Spectroscopic Studies of the Ferriheme Resonances of the Low- Spin Imidazole, Histamine and Cyanide Complexes of wt Nitrophorin 2 and NP2(V24E) as a Function of pH, J. Biol. Inorg. Chem. 2009, 14, 1077-1095.
R. E. Berry, M. N. Shokhirev, A. Y. W. Ho, F. Yang, T. K. Shokhireva, H. Zhang, A. Weichsel, W. R. Montfort, F. A. Walker. Effect of Mutation of Carboxylate Side-Chain Amino Acids Near the Heme on the Midpoint Potentials and Ligand Binding Constants of Nitrophorin 2 and its NO, Histamine and Imidazole Complexes, J. Am. Chem. Soc. 2009, 131, 2313-2327.
R. E. Berry, T. Kh. Shokhireva, I. Filippov, M. N. Shokhirev, H. Zhang, F. A. Walker. Effect of the N-Terminus on Heme Cavity Structure, Ligand Equilibrium and Rate Constants, and Reduction Potentials of Nitrophorin 2 from Rhodnius prolixus, Biochemistry 2007, 46, 6830-6843.
T. K. Shokhireva, A. Weichsel, K. M. Smith, R. E. Berry, N. V. Shokhirev, C. A. Balfour, H. J. Zhang, W. R. Montfort, F. A. Walker. Assignment of the ferriheme resonances of the low-spin complexes of nitrophorins 1 and 4 by H-1 and C-13 NMR spectroscopy: Comparison to structural data obtained from X-ray crystallography. Inorg. Chem. 2007, 46 (6), 2041-2056.
T. K. Shokhireva, K. M. Smith, R. E. Berry, et al. Assignment of the ferriheme resonances of the high-spin forms of nitrophorins 1 and 4 by H-1 NMR spectroscopy: Comparison to structural data obtained from X-ray crystallography. Inorg. Chem. 2007, 46 (1), 170-178.
S. Cai, T. K. Shokhireva, D. L. Lichtenberger, et al. NMR and EPR studies of chloroiron(III) tetraphenyl-chlorin and its complexes with imidazoles and pyridines of widely differing basicities Inorg. Chem. 2006, 45 (9), 3519-3531.
A. Weichsel, E. M. Maes, J. E. Andersen, J. G. Valenzuela, T. K. Shokhireva, F. A. Walker, W. R. Montfort. Heme-assisted S-nitrosation of a proximal thiolate in a nitric oxide transport protein. PNAS USA 2005, 102 (3): 594-599.
S. Nardis, S. Licoccia, F. R. Fronczec, M. G. H. Vicente, T. Kh. Shokhireva, F. A. Walker. NMR and structural investigations of nonplanar iron corrolates: Modified patterns of spin delocalization and coupling in slightly saddled chloroiron(III) corrolate radicals. Inorg. Chem. 2005, 44, 7030-7046.
A. Weichsel, E. M. Maes, J. F. Andersen, J.G. Valenzuela, T. Kh. Shokhireva, F. A. Walker, W. R. Montfort. Heme-assisted S-nitrosation of a proximal thiolate in a nitric oxide transport protein. PNAS USA 2005, 102,:594-599.
R. E. Berry, X.D.Ding, T. Kh.Shokhireva, A.Weichsel, W.R.Montfort , F.A.Walker . Axial ligand complexes of the Rhodnius nitrophorins: reduction potentials, binding constants, EPR spectra, and structures of the 4-iodopyrazole and imidazole complexes of NP4. J. Biol. Inorg. Chem. 2004, 9, 135-144.
T. Kh. Shokhireva, R. E. Berry, E. Uno, Celia A. Balfour, H. Zhang, F. A.Walker. Electrochemical and NMR spectroscopic studies of distal pocket mutants of nitrophorin 2: Stability, structure, and dynamics of axial ligand complexes. PNAS USA 2003, 100, 3778-3783.
T. Kh. Shokhireva, N. V. Shokhirev, F. A. Walker, Assignment of Heme Resonances and Determination of the Electronic Structures of High- and Low-Spin Nitrophorin 2 by 1H and 13C NMR Spectroscopy: An Explanation of the Order of Heme Methyl Resonances in High-Spin Ferriheme Proteins. Biochemistry. 2003, 42, 679-693.
G.A. Caignan, A.M.Rivera, Astashkin, A. M. Raitsimring, T. Kh. Shokhireva, F. A. Walker. Models of the Low-Spin Iron(III) Hydroperoxide Intermediate of Heme Oxygenase: Magnetic Resonance Evidence for Thermodynamic Stabilization of the dxy Electronic State at Ambient Temperatures. J. Am. Chem. Soc. 2002, 124, 6077-6089.
M. Rivera , G.A. Caignan, A.V. Astashkin , A.M. Raitsimring , T.Kh. Shokhireva, F. A. Walker. Models of the low-spin iron(III) hydroperoxide intermediate of heme oxygenase: magnetic resonance evidence for thermodynamic stabilization of the d(xy) electronic state at ambient temperatures. J. Am. Chem. Soc. 2002, 124, 6077-89.
A.V. Astashkin, A.M. Raitsimring, A.R.Kennedy, T.Kh. Shokhireva, F. A.Walker. Pulsed EPR Characterization of the Low-Spin Iron(III) Porphyrinate Complexes with Phenyl Isocyanide Ligands Having the dxy Orbital Ground State. J. Phys.Chem. A. 2002, 106, 74-82.
M. Rivera, G. A. Caignan, A.V. Astashkin, A. M. Raitsimring, T. Kh. Shokhireva, F. A. Walker.NMR and Pulsed ENDOR Evidence for Thermodynamic Stabilization of the dxy Electronic Ground State in Low-Spin Ferriheme Models of Heme Oxygenase: Implications for the Reactivity of the Iron(III) Hydroperoxide Intermediate. J. Inorg. Biochem. 2001, 86, 474.
J. F. Andersen, X. D. Ding, C. Balfour, T. Kh. Shokhireva, D. E.Champagne, F. A. Walker, W. R. Montfort, . Kinetics and Equilibria in Ligand Binding by Nitrophorins 1-4: Evidence for Stabilization of a Nitric Oxide-Ferriheme Complex through a Ligand-Induced Conformational Trap. Biochemistry. 2000, 39, 10118-10131.
O. Q. Munro, J. A. Serth-Guzzo, I.Turowska-Tyrk, K. Mohanrao, T. Kh. Shokhireva, F. A. Walker, P. G. Debrunner, W.R. Scheidt. Two Crystalline Forms of Low-Spin [Fe(TMP)(5-MeHIm)2]ClO4. Relative Parallel and Perpendicular Axial Ligand Orientations. J. Am.Chem.Soc. 2000, 122, 2144.
M. J. M. Nesset, S. Cai, T.Kh. Shokhireva, N.V. Shokhirev, S.E.Jacobson, K.Jayaraj, A. Gold, F.A.Walker. Electronic Effects in Transition Metal Porphyrins. 10. Effect of Ortho Substituents on the Temperature Dependence of the NMR Spectra of a Series of Spin-Admixed Perchloratoiron(III) Tetrakis(2,6- or 2,4,6-phenyl substituted)porphyrinates. Inorg.Chem.. 2000, 39, 532-540.
V. Schünemann, A. M. Raitsimring, R. Benda, A. X. Trautwein, T. Kh. Shokhireva, F. A. Walker. ESEEM and Mössbauer Studies of the Ferriheme Model Compound Tetraphenylporphyrinatoiron(III)-bis-(3-aminopyrazole), [TPPFe(NH2PzH)2]Cl. J. Biol. Inorg. Chem. 1999, 4, 708-716.
A. B. Minniear, T. Kh. Shokhireva, F. A. Walker. The Effect of Axial Ligand Plane Orientation on the Isotropic Shifts of Traylor and Berzinis Dichelated Protohemin Cyanide Complexes. Inorg. Chem. 1999, 38, 5856-5859.
F. A. Walker, J. F. Andersen, A. Weichsel, T. Kh. Shokhireva, A. V. Astashkin, X. D. Ding, C. Balfour, A. M. Raitsimring, W. R. Montfort. Structural, Spectroscopic and Electrochemical Comparisons of Three of the Four Nitrophorins (NO-Releasing Heme Proteins) from the Saliva of the Blood-Sucking Insect, Rhodnius prolixus. J. Inorg. Biochem. 1999, 74, 331.
X. D. Ding, A.Weichsel, C. Balfour, T. Kh. Shokhireva, Pierik, A. Averill, B. A. W. R. Montfort, F. A. Walker. Nitric Oxide Binding to the Ferri- and Ferroheme States of Nitrophorin 1, a Reversible NO-Binding Heme Protein from the Saliva of a Blood-Sucking Insect, Rhodnius prolixus. J. Am. Chem. Soc. 1999, 121, 128-138.
T. Kh. Shokhireva, M. J. M. Nesset, F. A. Walker. ROESY Spectra of Paramagnetic Model Heme Complexes: Unambiguous Differentiation of Cross Peaks Due to Chemical Exchange and the Nuclear Overhauser Effect. Inorg. Chim. Acta 1998, 272, 204-210.
J. R. Polam, T. Kh. Shokhireva, Raffii, K., U. Simonis, F. A. Walker. Rates of Axial Ligand Rotation in Diamagnetic d6 Co(III) and Fe(II) Tetramesitylporphyrinates. Inorg. Chim. Acta. 1997, 263, 109-117.
N. V. Shokhirev, T. Kh. Shokhireva, J. R. Polam, C. T. Watson, K. Raffii, U. Simonis, F. A. Walker. 2-D NMR Investigations of axial ligands in six-coordinate low-spin Iron(III) and Cobalt (III) tetraphenylporphyrinates having 2,6-phenyl substituents: Measurement of rate constant from 1H EXSY cross-peak intensities. J. Phys. Chem. A, 1997, 101, 2778-2786.
A. M. Raitsimring, P. Borbat, T. Kh. Shokhireva, F. A. Walker. Magnetic Field (g-Value) Dependence of Proton Hyperfine Couplings Obtained from ESEEM Measurements: Determination of the Orientation of the Magnetic Axes of Model Heme Complexes in Glassy Media. J. Phys. Chem. 1996, 100, 5235-5244.