The different intermolecular interactions of the soluble copper-binding domains of the menkes protein, ATP7A.
ATP7A is a P-type ATPase involved in copper(I) homeostasis in humans. It possesses a long N-terminal cytosolic tail containing six domains that are individually folded and capable of binding one copper(I) ion each. We investigated the entire N-terminal tail (MNK1-6) in solution by NMR spectroscopy and addressed its interaction with copper(I) and with copper(I)-HAH1, the physiological partner of ATP7A. At copper(I)-HAH1:MNK1-6 ratios of up to 3:1, thus encompassing the range of protein ratios in vivo, both the first and fourth domain of the tail formed a metal-mediated adduct with HAH1 whereas the sixth domain was simultaneously able to partly remove copper(I) from HAH1. These processes are not dependent on one another. In particular, formation of the adducts is not necessary for copper(I) transfer from HAH1 to the sixth domain. The present data, together with available in vivo studies, suggest that the localization of ATP7A between the trans-Golgi network and the plasma membrane may be regulated by the accumulation of the adducts with HAH1, whereas the main role of domains 5 and 6 is to assist copper(I) translocation.
Banci
Lucia
L
Magnetic Resonance Center, Via L. Sacconi 6, and Department of Chemistry, Via della Lastruccia 3, University of Florence, Italy.
Bertini
Ivano
I
Cantini
Francesca
F
Della-Malva
Nunzia
N
Migliardi
Manuele
M
Rosato
Antonio
A
D000251:Adenosine Triphosphatases / Q000737:chemistry*; D027682:Cation Transport Proteins / Q000737:chemistry*; D045744:Cell Line, Tumor; D003300:Copper / Q000737:chemistry*; D000079922:Copper Transport Proteins; D000073840:Copper-Transporting ATPases; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D056511:Metallochaperones; D008670:Metals / Q000737:chemistry; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D021381:Protein Transport
C474500:ATOX1 protein, human; D027682:Cation Transport Proteins; D000079922:Copper Transport Proteins; D056511:Metallochaperones; D008670:Metals; D018832:Molecular Chaperones; D003300:Copper; D000251:Adenosine Triphosphatases; C081184:ATP7A protein, human; D000073840:Copper-Transporting ATPases