A ligand field model for MCD spectra of biological cupric complexes

G. A. Landrum, C. A. Ekberg, J. W. Whittaker

Research output: Contribution to journalArticle

15 Scopus citations

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 sigma, pi 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
DOIs
StatePublished - Jan 1 1995

ASJC Scopus subject areas

  • Biophysics

Fingerprint Dive into the research topics of 'A ligand field model for MCD spectra of biological cupric complexes'. Together they form a unique fingerprint.

  • Cite this