A ligand field model for MCD spectra of biological cupric complexes

G. A. Landrum, C. A. Ekberg, James Whittaker

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

A ligand field calculation of magnetic circular dichroism (MCD) spectra is described that provides new insights into the information contained in electronic spectra of copper sites in metalloenzymes and synthetic analogs. The ligand field model uses metal-centered p- and f-orbitals to model σ,π LMCT mixing mechanism for intensity, allowing the basic features of optical absorption, MCD, and electron paramagnetic resonance spectra to be simultaneously computed from a single set of parameters and the crystallographically determined ligand coordinates. We have used the model to predict changes in spectra resulting from the transformation of electronic wavefunctions under systematic variation in geometry in pentacoordinate ML5 complexes. The effectiveness of the calculation is demonstrated for two synthetic copper model compounds and a galactose oxidase enzyme complex representing limiting coordination geometries. This analysis permits immediate recognition of characteristic patterns of MCD intensity and correlation with geometry. A complementarity principle between MCD and CD spectra of transition metal complexes is discussed.

Original languageEnglish (US)
Pages (from-to)674-689
Number of pages16
JournalBiophysical Journal
Volume69
Issue number2
StatePublished - 1995
Externally publishedYes

Fingerprint

Magnetic Fields
Circular Dichroism
Ligands
Copper
Galactose Oxidase
Coordination Complexes
Electron Spin Resonance Spectroscopy
Metals
Enzymes

ASJC Scopus subject areas

  • Biophysics

Cite this

Landrum, G. A., Ekberg, C. A., & Whittaker, J. (1995). A ligand field model for MCD spectra of biological cupric complexes. Biophysical Journal, 69(2), 674-689.

A ligand field model for MCD spectra of biological cupric complexes. / Landrum, G. A.; Ekberg, C. A.; Whittaker, James.

In: Biophysical Journal, Vol. 69, No. 2, 1995, p. 674-689.

Research output: Contribution to journalArticle

Landrum, GA, Ekberg, CA & Whittaker, J 1995, 'A ligand field model for MCD spectra of biological cupric complexes', Biophysical Journal, vol. 69, no. 2, pp. 674-689.
Landrum GA, Ekberg CA, Whittaker J. A ligand field model for MCD spectra of biological cupric complexes. Biophysical Journal. 1995;69(2):674-689.
Landrum, G. A. ; Ekberg, C. A. ; Whittaker, James. / A ligand field model for MCD spectra of biological cupric complexes. In: Biophysical Journal. 1995 ; Vol. 69, No. 2. pp. 674-689.
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