4QOT

Crystal structure of human copper chaperone bound to the platinum ion


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.190 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Oxaliplatin Binding to Human Copper Chaperone Atox1 and Protein Dimerization

Belviso, B.D.Galliani, A.Lasorsa, A.Mirabelli, V.Caliandro, R.Arnesano, F.Natile, G.

(2016) Inorg Chem 55: 6563-6573

  • DOI: 10.1021/acs.inorgchem.6b00750
  • Primary Citation of Related Structures:  
    4QOT

  • PubMed Abstract: 
  • Copper trafficking proteins have been implicated in the cellular response to platinum anticancer drugs. We investigated the reaction of the chaperone Atox1 with an activated form of oxaliplatin, the third platinum drug to reach worldwide approval. Unlike cisplatin, which contains monodentate ammines, oxaliplatin contains chelated 1,2-diaminocyclohexane (DACH), which is more resistant to displacement by nucleophiles ...

    Copper trafficking proteins have been implicated in the cellular response to platinum anticancer drugs. We investigated the reaction of the chaperone Atox1 with an activated form of oxaliplatin, the third platinum drug to reach worldwide approval. Unlike cisplatin, which contains monodentate ammines, oxaliplatin contains chelated 1,2-diaminocyclohexane (DACH), which is more resistant to displacement by nucleophiles. In solution, one or two {Pt(DACH)(2+)} moieties bind to the conserved CXXC metal-binding motif of Atox1; in the latter case the two sulfur atoms likely bridging the two platinum units. At longer reaction times, a dimeric species is formed whose composition, Atox12·Pt(2+)2, indicates complete loss of the diamine ligands. Such a dimerization process is accompanied by partial unfolding of the protein. Crystallization experiments aiming at the characterization of the monomeric species have afforded, instead, a dimeric species resembling that already obtained by Boal and Rosenzweig in a similar reaction performed with cisplatin. However, while in the latter case there was only one Pt-binding site (0.4 occupancy) made of four sulfur atoms of the CXXC motifs of the two Atox1 chains in a tetrahedral arrangement, we found, in addition, a secondary Pt-binding site involving Cys41 of the B chain (0.25 occupancy). Moreover, both platinum atoms have lost their diamines. Thus, there appears to be little relationship between what is observed in solution and what is formed in the solid state. Since full occupancy of the tetrahedral cavity is a common feature of all Atox1 dimeric structures obtained with other metal ions (Cu(+), Cd(2+), and Hg(2+)), we propose that in the case of platinum, where the occupancy is only 0.4, the remaining cavities are occupied by Cu(+) ions. Experimental evidence is reported in support of the latter hypothesis. Our proposal represents a meeting point between the initial proposal of Boal and Rosenzweig (0.4 Pt occupancy) and the reinterpretation of the original crystallographic data put forward by Shabalin et al. (1 Cu occupancy), and could apply to other cases.


    Organizational Affiliation

    Department of Chemistry, University of Bari "A. Moro" , via E. Orabona 4, 70125 Bari, Italy.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Copper transport protein ATOX1A, B68Homo sapiensMutation(s): 0 
Gene Names: ATOX1HAH1
EC: 3.6.3.54
UniProt & NIH Common Fund Data Resources
Find proteins for O00244 (Homo sapiens)
Explore O00244 
Go to UniProtKB:  O00244
PHAROS:  O00244
GTEx:  ENSG00000177556 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO00244
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.190 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 78.055α = 90
b = 78.055β = 90
c = 54.628γ = 120
Software Package:
Software NamePurpose
MxCuBEdata collection
ILMILIONEmodel building
PHENIXrefinement
XDSdata reduction
SCALAdata scaling
ILMILIONEphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-06-24
    Type: Initial release
  • Version 1.1: 2016-10-26
    Changes: Database references