1wtf

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spinqualitylabelsall models 1wtf, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of Bacillus thermoproteolyticus Ferredoxin Variants Containing Unexpected [3Fe-4S] Cluster that is linked to Coenzyme A at 1.6 A Resolution

Overview

During the purification of recombinant Bacillus thermoproteolyticus, ferredoxin (BtFd) from Escherichia coli, we have noted that some Fe-S, proteins were produced in relatively small amounts compared to the, originally identified BtFd carrying a [4Fe-4S] cluster. These variants, could be purified into three Fe-S protein components (designated as V-I, V-II, and V-III) by standard chromatography procedures. UV-vis and EPR, spectroscopic analyses indicated that each of these variants accommodates, a [3Fe-4S] cluster. From mass spectrometric and protein sequence analyses, together with native and SDS gel electrophoresis, we established that V-I, and V-II contain the polypeptide of BtFd associated with acyl carrier, protein (ACP) and with coenzyme A (CoA), respectively, and that V-III is a, BtFd dimer linked by a disulfide bond. The crystal structure of the, BtFd-CoA complex (V-II) determined at 1.6 A resolution revealed that each, of the four complexes in the crystallographic asymmetric unit possesses a, [3Fe-4S] cluster that is coordinated by Cys(11), Cys(17), and Cys(61). The, polypeptide chain of each complex is superimposable onto that of the, original [4Fe-4S] BtFd except for the segment containing Cys(14), the, fourth ligand to the [4Fe-4S] cluster of BtFd. In the variant molecules, the side chain of Cys(14) is rotated away to the molecular surface, forming a disulfide bond with the terminal sulfhydryl group of CoA. This, covalent modification may have occurred in vivo, thereby preventing the, assembly of the [4Fe-4S] cluster as observed previously for Desulfovibrio, gigas ferredoxin. Possibilities concerning how the variant molecules are, formed in the cell are discussed.

About this Structure

1WTF is a Single protein structure of sequence from Bacillus thermoproteolyticus with SO4, COA and F3S as ligands. Full crystallographic information is available from OCA.

Reference

Identification of variant molecules of Bacillus thermoproteolyticus ferredoxin: crystal structure reveals bound coenzyme A and an unexpected [3Fe-4S] cluster associated with a canonical [4Fe-4S] ligand motif., Shirakawa T, Takahashi Y, Wada K, Hirota J, Takao T, Ohmori D, Fukuyama K, Biochemistry. 2005 Sep 20;44(37):12402-10. PMID:16156653

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