Structural and spectroscopic features of a cis (hydroxo)-Fe(III)-(carboxylato) configuration as an active site model for lipoxygenases

Inorg Chem. 2002 Oct 21;41(21):5513-20. doi: 10.1021/ic0200040.

Abstract

In our preliminary communication (Ogo, S.; Wada, S.; Watanabe, Y.; Iwase, M.; Wada, A.; Harata, M.; Jitsukawa, K.; Masuda, H.; Einaga, H. Angew. Chem., Int. Ed. 1998, 37, 2102-2104), we reported the first example of X-ray analysis of a mononuclear six-coordinate (hydroxo)iron(III) non-heme complex, [Fe(III)(tnpa)(OH)(RCO(2))]ClO(4) [tnpa = tris(6-neopentylamino-2-pyridylmethyl)amine; for 1, R = C(6)H(5)], which has a characteristic cis (hydroxo)-Fe(III)-(carboxylato) configuration that models the cis (hydroxo)-Fe(III)-(carboxylato) moiety of the proposed (hydroxo)iron(III) species of lipoxygenases. In this full account, we report structural and spectroscopic characterization of the cis (hydroxo)-Fe(III)-(carboxylato) configuration by extending the model complexes from 1 to [Fe(III)(tnpa)(OH)(RCO(2))]ClO(4) (2, R = CH(3); 3, R = H) whose cis (hydroxo)-Fe(III)-(carboxylato) moieties are isotopically labeled by (18)OH(-), (16)OD(-), (18)OD(-), (12)CH(3)(12)C(18)O(2)(-), (12)CH(3)(13)C(16)O(2)(-), (13)CH(3)(12)C(16)O(2)(-), (13)CH(3)(13)C(16)O(2)(-), and H(13)C(16)O(2)(-). Complexes 1-3 are characterized by X-ray analysis, IR, EPR, and UV-vis spectroscopy, and electrospray ionization mass spectrometry (ESI-MS).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / chemistry
  • Binding Sites
  • Crystallography, X-Ray
  • Electrochemistry
  • Electron Spin Resonance Spectroscopy
  • Indicators and Reagents
  • Isotope Labeling
  • Ligands
  • Lipoxygenase / chemistry*
  • Models, Molecular
  • Molecular Conformation
  • Spectrometry, Mass, Electrospray Ionization
  • Spectrophotometry, Infrared
  • Spectrophotometry, Ultraviolet
  • Stereoisomerism

Substances

  • Acetates
  • Indicators and Reagents
  • Ligands
  • Lipoxygenase