Linked Life Data

21646353

Source:http://linkedlifedata.com/resource/pubmed/id/21646353

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
30
pubmed:dateCreated
2011-7-25
pubmed:abstractText
The copper-transporting ATPase ATP7A has an essential role in human physiology. ATP7A transfers the copper cofactor to metalloenzymes within the secretory pathway; inactivation of ATP7A results in an untreatable neurodegenerative disorder, Menkes disease. Presently, the mechanism of ATP7A-mediated copper release into the secretory pathway is not understood. We demonstrate that the characteristic His/Met-rich segment Met(672)-Pro(707) (HM-loop) that connects the first two transmembrane segments of ATP7A is important for copper release. Mutations within this loop do not prevent the ability of ATP7A to form a phosphorylated intermediate during ATP hydrolysis but inhibit subsequent dephosphorylation, a step associated with copper release. The HM-loop inserted into a scaffold protein forms two structurally distinct binding sites and coordinates copper in a mixed His-Met environment with an ?2:1 stoichiometry. Binding of either copper or silver, a Cu(I) analog, induces structural changes in the loop. Mutations of 4 Met residues to Ile or two His-His pairs to Ala-Gly decrease affinity for copper. Altogether, the data suggest a two-step process, where copper released from the transport sites binds to the first His(Met)(2) site, triggering a structural change and binding to a second 2-coordinate His-His or His-Met site. We also show that copper binding within the HM-loop stabilizes Cu(I) and protects it from oxidation, which may further aid the transfer of copper from ATP7A to acceptor proteins. The mechanism of copper entry into the secretory pathway is discussed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
29
pubmed:volume
286
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
26585-94
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
The lumenal loop Met672-Pro707 of copper-transporting ATPase ATP7A binds metals and facilitates copper release from the intramembrane sites.
pubmed:affiliation
From the Department of Physiology, Johns Hopkins University, Baltimore, Maryland 21205, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural