1nip

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spinqualitylabelsall models 1nip, resolution 2.9Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTALLOGRAPHIC STRUCTURE OF THE NITROGENASE IRON PROTEIN FROM AZOTOBACTER VINELANDII

Overview

The nitrogenase enzyme system catalyzes the ATP (adenosine, triphosphate)-dependent reduction of dinitrogen to ammonia during the, process of nitrogen fixation. Nitrogenase consists of two proteins: the, iron (Fe)-protein, which couples hydrolysis of ATP to electron transfer, and the molybdenum-iron (MoFe)-protein, which contains the dinitrogen, binding site. In order to address the role of ATP in nitrogen fixation, the crystal structure of the nitrogenase Fe-protein from Azotobacter, vinelandii has been determined at 2.9 angstrom (A) resolution. Fe-protein, is a dimer of two identical subunits that coordinate a single 4Fe:4S, cluster. Each subunit folds as a single alpha/beta type domain, which, together symmetrically ligate the surface exposed 4Fe:4S cluster through, two cysteines from each subunit. A single bound ADP (adenosine, diphosphate) molecule is located in the interface region between the two, subunits. Because the phosphate groups of this nucleotide are, approximately 20 A from the 4Fe:4S cluster, it is unlikely that ATP, hydrolysis and electron transfer are directly coupled. Instead, it appears, that interactions between the nucleotide and cluster sites must be, indirectly coupled by allosteric changes occurring at the subunit, interface. The coupling between protein conformation and nucleotide, hydrolysis in Fe-protein exhibits general similarities to the H-Ras p21, and recA proteins that have been recently characterized structurally. The, Fe-protein structure may be relevant to the functioning of other, biochemical energy-transducing systems containing two nucleotide-binding, sites, including membrane transport proteins.

About this Structure

1NIP is a Single protein structure of sequence from Azotobacter vinelandii with MG, SF4 and ADP as ligands. Full crystallographic information is available from OCA.

Reference

Crystallographic structure of the nitrogenase iron protein from Azotobacter vinelandii., Georgiadis MM, Komiya H, Chakrabarti P, Woo D, Kornuc JJ, Rees DC, Science. 1992 Sep 18;257(5077):1653-9. PMID:1529353

Page seeded by OCA on Tue Nov 20 22:17:56 2007