Linked Life Data

11601974

Source:http://linkedlifedata.com/resource/pubmed/id/11601974

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
42
pubmed:dateCreated
2001-10-16
pubmed:abstractText
This paper describes a novel approach to specific oxidative cleavage of Na(+),K(+)-ATPase, mediated by Cu(2+) ions and a hydrophobic phenanthroline, 4,7-diphenyl-1,10-phenanthroline (DPP), in the presence of ascorbate and H(2)O(2). The cleavage produces two major fragments of the alpha subunit, with apparent molecular masses of 96.5 and 76 kDa, and N-termini near the cytoplasmic entrance of transmembrane segments M1 and M3, respectively, The kinetics indicate that both cleavages are mediated by a single Cu(2+)-DPP complex. We infer that M3 and M1 are in proximity near the cytoplasmic surface. The yields of 96.5 and 76 kDa fragments are not significantly affected by ligands that stabilize different E(1) and E(2) conformations. In E(2)(K) and E(2)P conformations, a minor 5.5 kDa fragment with its N-terminus in M10 is also observed. The 96.5 and 76 kDa fragments are indistinguishable from two fragments near M3 and M1 produced by Fe(2+)-catalyzed cleavage described previously [Goldshleger, R., and Karlish, S. J. D. (1999) J. Biol. Chem. 274, 16213-16221], whereas other Fe(2+)-catalyzed cleavage fragments in the cytoplasmic P and A domains are not observed with the Cu(2+)-DPP complex. These findings provide experimental support for the concept of two separate Fe(2+) sites. A homology model, with Na(+),K(+)-ATPase residues within transmembrane segments and connecting loops substituted into the crystal structure of Ca(2+)-ATPase, shows the proximity between the sequences HFIH in M3 and EVWK in M1, near the cytoplasmic surface. Thus, the model strongly supports the conclusions based on cleavages mediated by the Cu(2+)-DPP complex (or Fe(2+) at site 2). As a corollary, the cleavages provide evidence for similar packing of M1 and M3 of Na(+),K(+)-ATPase and Ca(2+)-ATPase.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12505-14
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:11601974-Amino Acid Sequence, pubmed-meshheading:11601974-Animals, pubmed-meshheading:11601974-Binding Sites, pubmed-meshheading:11601974-Catalysis, pubmed-meshheading:11601974-Cations, Divalent, pubmed-meshheading:11601974-Chelating Agents, pubmed-meshheading:11601974-Computer Simulation, pubmed-meshheading:11601974-Copper, pubmed-meshheading:11601974-Hydrolysis, pubmed-meshheading:11601974-Membrane Proteins, pubmed-meshheading:11601974-Models, Molecular, pubmed-meshheading:11601974-Molecular Sequence Data, pubmed-meshheading:11601974-Oxidation-Reduction, pubmed-meshheading:11601974-Peptide Fragments, pubmed-meshheading:11601974-Phenanthrolines, pubmed-meshheading:11601974-Protein Structure, Secondary, pubmed-meshheading:11601974-Sequence Homology, Amino Acid, pubmed-meshheading:11601974-Sodium-Potassium-Exchanging ATPase, pubmed-meshheading:11601974-Swine
pubmed:year
2001
pubmed:articleTitle
Proximity of transmembrane segments M3 and M1 of the alpha subunit of Na+,K+-ATPase revealed by specific oxidative cleavage mediated by a complex of Cu2+ ions and 4,7-diphenyl-1,10-phenanthroline.
pubmed:affiliation
Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't