X-ray absorption of Azotobacter vinelandii vanadium nitrogenase

Journal Article · Wed Jun 08 00:00:00 EDT 1988 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00220a066· OSTI ID:7200510

George, G N; Coyle, C L; Hales, B J; Cramer, S P

Evidence for the existence of a vanadium-containing nitrogenase has existed for more than half a century, but progress in understanding this enzyme has only come recently. In 1980, Bishop and co-workers proposed that an alternative nitrogen-fixing enzyme exists in Azotobacter vinelandii and subsequently proposed that vanadium was involved. In 1986, Robson et al. demonstrated clearly that the alternate nitrogenase from Azotobacter chroococcum, Acl*, contained vanadium instead of molybdenum. Hales et al. have shown the vanadium is also found in the Azotobacter vinelandii alternative component I, Avl'. The molybdenum and vanadium nitrogenase proteins are similar in many respects. Like the molybdenum enzyme, both Acl* and Avl' exhibit an EPR spectrum characteristic of a species with an S = 3/2 ground state; Avl' also contains the so-called P-clusters. Additionally Acl* has recently been shown to possess an N-methylformamide soluble cofactor, FeVco, analogous to the well-known iron-molybdenum cofactor FeMoco. Arber et al. have reported X-ray absorption spectra for the Acl* enzyme and interpreted the EXAFS as evidence for a V-Fe-S cluster. The local vanadium structure is proposed to resemble a recently synthesized cubane-like VFe/sub 3/S/sub 4/ cluster, and analogies are drawn with the EXAFS-derived structure reported for the molybdenum nitrogenases. The authors report herein an X-ray absorption spectroscopic study of A. vinelandii vanadium nitrogenase, Avl', which supports and extends the work of Arber et al.

• Research Organization: Exxon Research and Engineering Company, Annandale, NJ (USA)
• OSTI ID: 7200510
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Journal Issue: 12 Vol. 110:12; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ABSORPTION SPECTROSCOPY
DATA
ELECTROMAGNETIC RADIATION
ELEMENTS
ENZYMES
EXPERIMENTAL DATA
INFORMATION
IONIZING RADIATIONS
METALS
NITRO-GROUP DEHYDROGENASES
NITROGENASE
NUMERICAL DATA
OXIDOREDUCTASES
RADIATIONS
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
TRANSITION ELEMENTS
VANADIUM
X RADIATION