Solution structure of the Wilson ATPase N-domain in the presence of ATP
[ATP7B_HUMAN] Defects in ATP7B are the cause of Wilson disease (WD) [MIM:277900]. WD is an autosomal recessive disorder of copper metabolism in which copper cannot be incorporated into ceruloplasmin in liver, and cannot be excreted from the liver into the bile. Copper accumulates in the liver and subsequently in the brain and kidney. The disease is characterized by neurologic manifestations and signs of cirrhosis.                                                  
[ATP7B_HUMAN] Involved in the export of copper out of the cells, such as the efflux of hepatic copper into the bile.
Publication Abstract from PubMed
Wilson disease protein (ATP7B) is a copper-transporting P(1B)-type ATPase that regulates copper homeostasis and biosynthesis of copper-containing enzymes in human tissues. Inactivation of ATP7B or related ATP7A leads to severe neurodegenerative disorders, whereas their overexpression contributes to cancer cell resistance to chemotherapeutics. Copper-transporting ATPases differ from other P-type ATPases in their topology and the sequence of their nucleotide-binding domain (N-domain). To gain insight into the structural basis of ATP7B function, we have solved the structure of the ATP7B N-domain in the presence of ATP by using heteronuclear multidimensional NMR spectroscopy. The N-domain consists of a six-stranded beta-sheet with two adjacent alpha-helical hairpins and, unexpectedly, shows higher similarity to the bacterial K(+)-transporting ATPase KdpB than to the mammalian Ca(2+)-ATPase or Na(+),K(+)-ATPase. The common core structure of P-type ATPases is retained in the 3D fold of the N-domain; however, the nucleotide coordination environment of ATP7B within this fold is different. The residues H1069, G1099, G1101, I1102, G1149, and N1150 conserved in the P(1B)-ATPase subfamily contribute to ATP binding. Analysis of the frequent disease mutation H1069Q demonstrates that this mutation does not significantly affect the structure of the N-domain but prevents tight binding of ATP. The structure of the N-domain accounts for the disruptive effects of >30 known Wilson disease mutations. The unique features of the N-domain provide a structural basis for the development of specific inhibitors and regulators of ATP7B.
Solution structure of the N-domain of Wilson disease protein: distinct nucleotide-binding environment and effects of disease mutations.,Dmitriev O, Tsivkovskii R, Abildgaard F, Morgan CT, Markley JL, Lutsenko S Proc Natl Acad Sci U S A. 2006 Apr 4;103(14):5302-7. Epub 2006 Mar 27. PMID:16567646
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.