The overall goal of the proposed research is the elucidation of the geometrical and electronic structures of the active sites of metalloproteins. The principal techniques to be employed involve optical spectroscopy using polarized light and (in part) magnetic fields, specifically circular dichroism (CD) and magnetic circular dichroism (MCD). We also propose to develop new instrumentation and theory for the study of magnetic linear dichroism (MLD). Selected metalloproteins will be studied by CD, MCD and MLD over wide ranges of temperatures, magnetic fields and wavelengths, respectively 1.2-300degreesK, 0-7 Tesla and 180-5000 nm. Spectra of a specific metalloprotein will be obtained in all accesible redox states. Spectra will then be analysed in order to determine as far as possible the nature of the metal-containing prosthetic groups of the proteins under study. Specific metalloproteins to be studied include the iron-sulfur (Fe-S) proteins: Desulfovibrio vulgaris hydrogenase, Klebsiella pneumoniae pyruvate-flavodoxin oxidoreductase, and Micrococcus aerogenes ferredoxin and the nickel-iron-sulfur enzyme: Azotobacter vinelandii hydrogenase. In all cases these metalloproteins are """"""""complex"""""""" possessing multiple metal-containing prosthetic groups in the enzymatically active states of the proteins. In the case of M. aerogenes ferredoxin, we will study the oxidative and degradative chemistry induced by Fe(CN)3,6- and similar oxidants. The metalloproteins to be studied are prototypical of classes of enzymes increasingly found in all types of living systems. They are involved in crucial physiological processes. The understanding of these and related enzymes at the chemical level is fundamental to the complete understanding of the workings of living cells, and eventually, to our ability to prevent and cure pathological conditions in cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM028386-07
Application #
3275713
Study Section
Metallobiochemistry Study Section (BMT)
Project Start
1981-02-01
Project End
1991-06-30
Budget Start
1987-07-01
Budget End
1988-06-30
Support Year
7
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Southern California
Department
Type
Schools of Arts and Sciences
DUNS #
041544081
City
Los Angeles
State
CA
Country
United States
Zip Code
90033
Langen, R; Jensen, G M; Jacob, U et al. (1992) Protein control of iron-sulfur cluster redox potentials. J Biol Chem 267:25625-7
Simpkin, D; Palmer, G; Devlin, F J et al. (1989) The axial ligands of heme in cytochromes: a near-infrared magnetic circular dichroism study of yeast cytochromes c, c1, and b and spinach cytochrome f. Biochemistry 28:8033-9