Conserved residue modulates copper-binding properties through structural dynamics in human copper chaperone Atox1

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• The human copper chaperone Atox1 is essential for intracellular copper transport.
• Lysine 60 (Lys60) is a conserved residue in Atox1, implicated in stabilizing its interaction with target proteins like ATP7A.
• Previous studies suggest the K60A mutation may impair copper transfer.

Purpose of the Study:

• To determine the structure and analyze the dynamics of Atox1 with the K60A mutation.
• To elucidate the specific role of the conserved Lys60 residue in copper transport by Atox1.

Main Methods:

• X-ray crystallography for structure determination of the Atox1 K60A mutant.
• Molecular dynamics simulations to analyze protein flexibility and metal-binding site dynamics.
• Assessment of copper-binding stability and hetero-protein interactions with ATP7A.

Main Results:

• The K60A mutation induced significant secondary structure rearrangements and altered the orientation of metal-binding residues in Atox1.
• Dynamic analyses revealed increased overall flexibility and altered dynamic properties of metal-binding sites in the K60A mutant.
• Copper-binding stability was decreased in the K60A mutant, though Cu(I)-mediated interactions with ATP7A persisted with less structural perturbation.

Conclusions:

• Lys60 is critical for maintaining the structural integrity and dynamic properties of Atox1.
• Alterations in structure and dynamics due to the K60A mutation directly impact copper-binding stability and cellular copper transport.
• Atox1's function in copper transfer involves dynamic interactions with ATP7A, influenced by residues like Lys60.