Structure and dimerization properties of the plant-specific copper chaperone CCH

Area of Science:

• Biochemistry
• Molecular Biology
• Plant Science

Background:

• Copper chaperones like ATX1 transport copper ions in cells.
• Plant ATX1 family includes ATX1 and CCH, a unique copper chaperone.
• CCH has an unknown C-terminal extension, predicted to be disordered.

Purpose of the Study:

• Investigate the structure and function of CCH's C-terminal extension.
• Determine the role of the extension in copper binding and dimerization.
• Confirm if the extension is intrinsically disordered.

Main Methods:

• Solution Nuclear Magnetic Resonance (NMR) spectroscopy.
• Biophysical analyses of purified CCH and a variant (CCHΔ).
• Computational studies on chaperone dimerization.

Main Results:

• The C-terminal extension of CCH is intrinsically disordered.
• The extension stabilizes CCH dimerization in both copper-free and copper-bound states.
• CCHΔ exhibits weaker dimerization but retains copper binding.

Conclusions:

• The C-terminal extension is crucial for CCH dimerization.
• This extension plays a significant role in copper ion transport regulation in plants.
• Identified key residues essential for maintaining dimer stability.