1blu

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spinqualitylabelsall models 1blu, resolution 2.1Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURE OF THE 2[4FE-4S] FERREDOXIN FROM CHROMATIUM VINOSUM

Overview

The crystal structure of the 2[4Fe-4S] ferredoxin from Chromatium vinosum, has been solved by molecular replacement using data recorded with, synchrotron radiation. The crystals were hexagonal prisms that showed a, strong tendency to develop into long tubes. The hexagonal prisms, diffracted to 2.1 A resolution at best, and a structural model for C., vinosum ferredoxin has been built with a final R of 19.2%. The N-terminal, domain coordinates the two [4Fe-4S] clusters in a fold that is almost, identical to that of other known ferredoxins. However, the structure has, two unique features. One is a six-residue insertion between two ligands of, one cluster forming a two-turn external loop; this short loop changes the, conformation of the Cys 40 ligand compared to other ferredoxins and, hampers the building of one NH...S H-bond to one of the inorganic sulfurs., The other remarkable structural element is a 3.5-turn alpha-helix at the, C-terminus that covers one side of the same cluster and is linked to the, cluster-binding domain by a six-residue external chain segment. The charge, distribution is highly asymmetric over the molecule. The structure of C., vinosum ferredoxin strongly suggests divergent evolution for bacterial, [3/4Fe-4S] ferredoxins from a common ancestral cluster-binding core. The, unexpected slow intramolecular electron transfer rate between the clusters, in C. vinosum ferredoxin, compared to other similar proteins, may be, attributed to the unusual electronic properties of one of the clusters, arising from localized changes in its vicinity rather than to a global, structural rearrangement.

About this Structure

1BLU is a Single protein structure of sequence from Allochromatium vinosum with SF4 as ligand. Full crystallographic information is available from OCA.

Reference

Crystal structure of the 2[4Fe-4S] ferredoxin from Chromatium vinosum: evolutionary and mechanistic inferences for [3/4Fe-4S] ferredoxins., Moulis JM, Sieker LC, Wilson KS, Dauter Z, Protein Sci. 1996 Sep;5(9):1765-75. PMID:8880900

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