Lysine-60 in copper chaperone Atox1 plays an essential role in adduct formation with a target Wilson disease domain.
The mechanism by which the human copper (Cu) chaperone Atox1 delivers Cu to metal-binding domains of Wilson disease (WD) protein for insertion into cuproenzymes is unclear. Using near-UV circular dichroism as a new tool to probe chaperone-target interactions, in combination with gel filtration and molecular dynamics simulations, we here demonstrate that Atox1 forms a stable Cu-dependent adduct with the fourth metal-binding domain of WD (WD4). Using point-mutated Atox1 variants, we show that the adduct forms in the absence of conserved residues M10 or T11 but K60 is essential for heterocomplex formation and Cu transfer. Dissection of heterocomplex energetic components reveals a crucial role for K60-mediated electrostatic interaction.
Department of Biochemistry and Cell Biology, Rice University, 6100 Main Street, Houston, Texas 77251, USA.
Faiza
F
Hussain
Agustina
A
Rodriguez-Granillo
Pernilla
P
Wittung-Stafshede
D000251:Adenosine Triphosphatases / Q000737:chemistry*; D027682:Cation Transport Proteins / Q000737:chemistry*; D003198:Computer Simulation; D003300:Copper / Q000737:chemistry*; D000079922:Copper Transport Proteins; D000073840:Copper-Transporting ATPases; D006801:Humans; D008239:Lysine / Q000737:chemistry*; D056511:Metallochaperones; D008956:Models, Chemical; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry*; D011487:Protein Conformation
C474500:ATOX1 protein, human; D027682:Cation Transport Proteins; D000079922:Copper Transport Proteins; D056511:Metallochaperones; D018832:Molecular Chaperones; D003300:Copper; D000251:Adenosine Triphosphatases; D000073840:Copper-Transporting ATPases; D008239:Lysine