Cu(I) Controls Conformational States in Human Atox1 Metallochaperone: An EPR and Multiscale Simulation Study

Ortal Perkal, Zena Qasem, Meital Turgeman, Renana Schwartz, Lada Gevorkyan-Airapetov, Matic Pavlin, Alessandra Magistrato, Dan Thomas Major, Sharon Ruthstein

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Atox1 is a human copper metallochaperone that is responsible for transferring copper ions from the main human copper transporter, hCtr1, to ATP7A/B in the Golgi apparatus. Atox1 interacts with the Ctr1 C-terminal domain as a dimer, although it transfers the copper ions to ATP7A/B in a monomeric form. The copper binding site in the Atox1 dimer involves Cys12 and Cys15, while Lys60 was also suggested to play a role in the copper binding. We recently showed that Atox1 can adopt various conformational states, depending on the interacting protein. In the current study, we apply EPR experiments together with hybrid quantum mechanics-molecular mechanics molecular dynamics simulations using a recently developed semiempirical density functional theory approach, to better understand the effect of Atox1's conformational states on copper coordination. We propose that the flexibility of Atox1 occurs owing to protonation of one or more of the cysteine residues, and that Cys15 is an important residue for Atox1 dimerization, while Cys12 is a critical residue for Cu(I) binding. We also show that Lys60 electrostatically stabilizes the Cu(I)-Atox1 dimer.

Original languageEnglish
Pages (from-to)4399-4411
Number of pages13
JournalJournal of Physical Chemistry B
Volume124
Issue number22
DOIs
StatePublished - 4 Jun 2020

Bibliographical note

Publisher Copyright:
Copyright © 2020 American Chemical Society.

Funding

We acknowledge the support of ERC-STG, Grant 754365, given to S.R. We thank Prof. Q. Cui and Dr. D. Roston for help with use of SCCDFTB parameters for Cu(I). We thank Dr. Walke for help with UV–vis measurements.

FundersFunder number
ERC-STG
Horizon 2020 Framework Programme754365

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