5N6Y

Azotobacter vinelandii vanadium nitrogenase

Summary for 5N6Y

• Entry DOI: 10.2210/pdb5n6y/pdb
• Descriptor: Nitrogenase vanadium-iron protein alpha chain, Nitrogenase vanadium-iron protein beta chain, Nitrogenase vanadium-iron protein delta chain, ... (9 entities in total)
• Functional Keywords: nitrogenase metalloenzyme biological nitrogen fixation, oxidoreductase
• Biological source: Azotobacter vinelandii; More
• Total number of polymer chains: 6
• Total formula weight: 243750.71

Authors

Sippel, D.,Einsle, O. (deposition date: 2017-02-16, release date: 2017-07-26, Last modification date: 2024-05-08)

Primary citation

Sippel, D.,Einsle, O.
The structure of vanadium nitrogenase reveals an unusual bridging ligand.
Nat. Chem. Biol., 13:956-960, 2017

PubMed Abstract: Nitrogenases catalyze the reduction of dinitrogen (N) gas to ammonium at a complex heterometallic cofactor. This most commonly occurs at the FeMo cofactor (FeMoco), a [Mo-7Fe-9S-C] cluster whose exact reactivity and substrate-binding mode remain unknown. Alternative nitrogenases replace molybdenum with either vanadium or iron and differ in reactivity, most prominently in the ability of vanadium nitrogenase to reduce CO to hydrocarbons. Here we report the 1.35-Å structure of vanadium nitrogenase from Azotobacter vinelandii. The 240-kDa protein contains an additional α-helical subunit that is not present in molybdenum nitrogenase. The FeV cofactor (FeVco) is a [V-7Fe-8S-C] cluster with a homocitrate ligand to vanadium. Unexpectedly, it lacks one sulfide ion compared to FeMoco, which is replaced by a bridging ligand, likely a μ-1,3-carbonate. The anion fits into a pocket within the protein that is obstructed in molybdenum nitrogenase, and its different chemical character helps to rationalize the altered chemical properties of this unique N- and CO-fixing enzyme.

PubMed: 28692069
DOI: 10.1038/nchembio.2428

Experimental method

X-RAY DIFFRACTION (1.35 Å)