(4Fe-4S)-cluster-depleted Azotobacter vinelandii ferredoxin I: a new 3Fe iron-sulfur protein

Journal Article · Sun Sep 01 04:00:00 EDT 1985 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.82.17.5661· OSTI ID:6182261

Stephens, P J; Morgan, T V; Devlin, F; Penner-Hahn, J E; Hodgson, K O; Scott, R A; Stout, C D; Burgess, B K

Fe(CN)6T oxidation of the aerobically isolated 7Fe Azotobacter vinelandii ferredoxin I, (7Fe)FdI, is a degradative reaction. Destruction of the (4Fe-4S) cluster occurs first, followed by destruction of the (3Fe-3S) cluster. At a Fe(CN)6T /(7Fe)FdI concentration ratio of 20, the product is a mixture of apoprotein and protein containing only a (3Fe-3S) cluster, (3Fe)FdI. This protein mixture, after partial purification, has been characterized by absorption, CD, magnetic CD, and EPR and Fe x-ray absorption spectroscopies. EPR and magnetic CD spectra provide strong evidence that the (3Fe-3S) cluster in (3Fe)FdI is essentially identical in structure to that in (7Fe)FdI. Analysis of the extended x-ray absorption fine structure (EXAFS) of (3Fe)FdI finds Fe scattering at an average Fe...Fe distance of approx. =2.7 A. The structure of the oxidized (3Fe-3S) cluster in solutions of oxidized (3Fe)FdI, and, by extension, of oxidized (7Fe)FdI, is thus different from that obtained by x-ray crystallography on oxidized (7Fe)FdI. Possible interpretations of this result are discussed.

• Research Organization: Univ. of Southern California, Los Angeles
• OSTI ID: 6182261
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 82:17; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTROSCOPY
AZOTOBACTER
BACTERIA
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COMPLEXES
DICHROISM
ELECTRON SPIN RESONANCE
FERREDOXIN
IRON COMPLEXES
MAGNETIC RESONANCE
METALLOPROTEINS
MICROORGANISMS
ORGANIC COMPOUNDS
OXIDATION
PROTEINS
RESONANCE
SPECTROSCOPY
SULFUR COMPLEXES
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
X-RAY SPECTROSCOPY