2rml

File:2rml.jpg

Solution structure of the N-terminal soluble domains of Bacillus subtilis CopA

Overview

CopA, a P-type ATPase from Bacillus subtilis, plays a major role in the resistance of the cell to copper by effecting the export of the metal across the cytoplasmic membrane. The N-terminus of the protein features two soluble domains (a and b), that each contain a Cu(I)-binding motif, MTCAAC. We have generated a stable form of the wild-type two domain protein, CopAab, and determined its solution structure. This was found to be similar to that reported previously for a higher stability S46V variant, with minor differences mostly confined to the Ser46-containing beta3 strand of domain (a). Chemical shift analysis demonstrated that the two Cu(I)-binding motifs, located at different ends of the protein molecule, are both able to participate in Cu(I)-binding, and that Cu(I) is in rapid exchange between protein molecules. Surprisingly, UV-visible and fluorescence spectroscopy indicate very different modes of Cu(I)-binding below and above a level of 1 Cu(I) per protein, consistent with a major structural change occurring above 1 Cu(I)/CopAab. Analytical equilibrium centrifugation and gel filtration data show that this is a result of Cu(I)-mediated dimerization of the protein. The resulting species is highly luminescent, indicating the presence of a solvent-shielded Cu(I)-cluster.

About this Structure

2RML is a Single protein structure of sequence from Bacillus subtilis. Full crystallographic information is available from OCA.

Reference

Structure and Cu(I)-binding properties of the N-terminal soluble domains of Bacillus subtilis CopA., Singleton C, Banci L, Ciofi-Baffoni S, Tenori L, Kihlken M, Boetzel R, Le Brun N, Biochem J. 2008 Jan 23;. PMID:18215122 Page seeded by OCA on Thu Apr 24 09:29:50 2008

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