Recent applications of MCD spectroscopy to metalloenzymes

Magnetic circular dichroism (MCD) continues to be a powerful probe of metalloenzyme electronic and geometric structure, in addition to playing a major role in the determination of heme enzyme coordination geometries. Excited state electronic structure contributions to enzyme activity have been gleaned from C-term MCD studies, which are usually interpreted in the context of other spectroscopies, including electronic absorption and resonance Raman. The recent development of sophisticated methods for the analysis of variable-temperature, variable-field MCD have allowed the ground states of metalloenzyme active sites to be studied in detail, providing information on the electronic and geometric structure of the site. This has been especially informative for non-heme iron enzymes. In the past two years X-ray MCD has been shown to be a promising technique for the study of metalloenzymes.