Fe and Mo EXAFS of Azotobacter vinelandii nitrogenase inpartially oxidized and singly reduced forms

Journal Article · Wed Oct 11 04:00:00 EDT 1995 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja00145a012· OSTI ID:136264

Christiansen, J ^[1]; Tittsworth, R C; Hales, B J ^[2]; Cramer, S P ^[3]

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1. Univ. of California, Davis, CA (United States)
2. Louisiana State Univ., Baton Rouge, LA (United States)
3. Univ. of California, Berkeley, CA (United States)

Fe and Mo K-edge EXAFS spectra of the nitrogenase Mo-Fe protein in the indigo disulfonate (IDS) oxidized form and under slow turnover conditions have been recorded. The EXAFS of the one-electron reduced form E{sub 1} was obtained as a difference spectrum between the slow turnover and resting (E{sub 0}) spectra. Average Fe-S, Fe-Fe, and Fe-Mo distances of 2.33, 2.60, and 2.66A, respectively, along with a second Fe-Fe distance at 3.72 A were found for E{sub 1}. The IDS-oxidized MoFe protein contain spartially oxidized `P-clusters`. For this sample, average Fe-S,Fe-Fe, and Fe-Mo interactions at 2.31, 2.65, and 2.71 A, respectively, were found along with the long Fe-Fe interaction at 3.74 A. Combination of the current results with previous data on resting and thionin-oxidized nitrogenase shows a general trend a significant number of the metal-metal distances tend to contract as the enzyme becomes more reduced. 52 refs., 6 figs., 2 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 136264
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 40 Vol. 117; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
55 BIOLOGY AND MEDICINE
BASIC STUDIES
ABSORPTION SPECTRA
CRYSTAL STRUCTURE
ENZYMES
IRON
MOLECULAR STRUCTURE
MOLYBDENUM
NITROGENASE
OXIDATION
PROTEINS
REDUCTION