Copper-transporting P-type ATPases, which play important roles in trafficking Cu(I) across membranes for the biogenesis of copper proteins or for copper detoxification, contain a variable number of soluble metal-binding domains at their N-termini. It is increasingly apparent that these play an important role in regulating copper transport in a Cu(I)-responsive manner, but how they do this is unknown. CopA, a Cu(I)-transporter from Bacillus subtilis, contains two N-terminal soluble domains that are closely packed, with inter-domain interactions at two principal regions. Here, we sought to determine the extent to which the domains interact in the absence of their inter-domain covalent linker, and how their Cu(I)-binding properties are affected. Studies of a 1:1 mixture of separate CopAa and CopAb domains showed that the domains do not form a stable complex, with only indirect evidence of a weak interaction between them. Their Cu(I)-binding behaviour was distinct from that of the two domain protein and consistent with a lack of interaction between the domains. Cu(I)-mediated protein association was observed, but this occurred only between domains of the same type. Thus, the inter-domain covalent link between CopAa and CopAb is essential for inter-domain interactions and for Cu(I)-binding behaviour.
|Number of pages||8|
|Journal||Biochimica et Biophysica Acta (BBA) - Proteins & Proteomics|
|Early online date||14 Nov 2017|
|Publication status||Published - Feb 2018|
- Copper trafficking
- Metal transport