Structural changes induced by catalytic turnover at the molybdenum site of arabidopsis nitrate reductase

Journal Article · Wed Oct 20 04:00:00 EDT 1999 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja990310l· OSTI ID:20013672

George, G N; Mertens, J A; Campbell, W H

Assimilatory nitrate reductases catalyze the reduction of nitrate to nitrite, which is the first and rate-limiting step of nitrogen assimilation in algae, fungi, and higher plants. The nitrate reductase from the thale cress, Arabidopsis thaliana, is a dimer, with each of the {approximately} 103,000 molecular weight monomers containing one molybdenum associated with a single pterin dithiolene cofactor, a flavin adenine dinucleotide cofactor, and a cytochrome b-type heme. During the catalytic cycle, reducing equivalents in the form of NADH enter the enzyme at the flavin site and are subsequently transferred by intramolecular electron transfer via the heme to the molybdenum center, where the two-electron reduction of nitrate takes place. In this paper the authors present the Mo K-edge EXAFS of Arabidopsis nitrate reductase in three different forms: oxidized as-isolated, reduced, and oxidized after catalytic turnover of excess nitrate (nitrate-oxidized).

• Research Organization: Stanford Univ., CA (US)
• Sponsoring Organization: US Department of Energy; National Institutes of Health; National Science Foundation
• OSTI ID: 20013672
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 41 Vol. 121; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
ARABIDOPSIS
MOLYBDENUM COMPOUNDS
NITRATES
NITRITES
OXIDOREDUCTASES
REDUCTION