Abstract

We have collected Fe K-Edge XAS spectra for 11 ferric porphyrin compounds and the cpd I model [FeIV=O(TMP*)]+ in order to relate the intensity and multiplet splitting pattern of the 1s->3d pre-edge region to the geometric and electronic structure of the iron site. The ferric porphyrins studied fall into four categories: (1) 6-coordinate (low-spin) S=1/2; (2) 5-coordinate (high-spin) S=5/2; (3) 5-coordinate (spin admixed) S=5/2-3/2; (4) 6- coordinate (spin admixed) S=5/2-3/2. Our results conclusively show that the integrated intensity of the observed pre-edge features is diagnostic of these four classes. A detailed multiplet analysis of the 6-coordinate, low-spin complex [FeTMBPP]Cl has allowed for an experimental determination of the one-electron Fe ligand field state energies. To our knowledge, this represents the first direct measurement of the ligand field parameters for a ferric porphyrin. Interestingly, the information content of the pre-edge region is complementary to that obtainable by EPR spectroscopy. Extension of these methodologies should allow for detailed geometric and electronic structural information to be obtained on EPR silent ferrous porphyrins.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR001209-20
Application #
6119641
Study Section
Project Start
1999-03-01
Project End
2000-04-14
Budget Start
1998-10-01
Budget End
1999-09-30
Support Year
20
Fiscal Year
1999
Total Cost
Indirect Cost

  Institution

Name
Stanford University
Department
Type
DUNS #
800771545
City
Stanford
State
CA
Country
United States
Zip Code
94305

  Publications

Vickers, Chelsea; Liu, Feng; Abe, Kento et al. (2018) Endo-fucoidan hydrolases from glycoside hydrolase family 107 (GH107) display structural and mechanistic similarities to ?-l-fucosidases from GH29. J Biol Chem 293:18296-18308
Nguyen, Phong T; Lai, Jeffrey Y; Lee, Allen T et al. (2018) Noncanonical role for the binding protein in substrate uptake by the MetNI methionine ATP Binding Cassette (ABC) transporter. Proc Natl Acad Sci U S A 115:E10596-E10604
Aleman, Fernando; Tzarum, Netanel; Kong, Leopold et al. (2018) Immunogenetic and structural analysis of a class of HCV broadly neutralizing antibodies and their precursors. Proc Natl Acad Sci U S A 115:7569-7574
Herrera, Nadia; Maksaev, Grigory; Haswell, Elizabeth S et al. (2018) Elucidating a role for the cytoplasmic domain in the Mycobacterium tuberculosis mechanosensitive channel of large conductance. Sci Rep 8:14566
Lal, Neeraj K; Nagalakshmi, Ugrappa; Hurlburt, Nicholas K et al. (2018) The Receptor-like Cytoplasmic Kinase BIK1 Localizes to the Nucleus and Regulates Defense Hormone Expression during Plant Innate Immunity. Cell Host Microbe 23:485-497.e5
Pluvinage, Benjamin; Grondin, Julie M; Amundsen, Carolyn et al. (2018) Molecular basis of an agarose metabolic pathway acquired by a human intestinal symbiont. Nat Commun 9:1043
Beyerlein, Kenneth R; Jönsson, H Olof; Alonso-Mori, Roberto et al. (2018) Ultrafast nonthermal heating of water initiated by an X-ray Free-Electron Laser. Proc Natl Acad Sci U S A 115:5652-5657
Yoshizawa, Takuya; Ali, Rustam; Jiou, Jenny et al. (2018) Nuclear Import Receptor Inhibits Phase Separation of FUS through Binding to Multiple Sites. Cell 173:693-705.e22
Morrison, Christine N; Spatzal, Thomas; Rees, Douglas C (2017) Reversible Protonated Resting State of the Nitrogenase Active Site. J Am Chem Soc 139:10856-10862
Zhang, Haonan; Qiao, Anna; Yang, Dehua et al. (2017) Structure of the full-length glucagon class B G-protein-coupled receptor. Nature 546:259-264

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