Linked Life Data

19396973

Source:http://linkedlifedata.com/resource/pubmed/id/19396973

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2009-4-24
pubmed:databankReference
pubmed:abstractText
NhaA, the main sodium-proton exchanger in the inner membrane of Escherichia coli, regulates the cytosolic concentrations of H+ and Na+. It is inactive at acidic pH, becomes active between pH 6 and pH 7, and reaches maximum activity at pH 8. By cryo-electron microscopy of two-dimensional crystals grown at pH 4 and incubated at higher pH, we identified two sequential conformational changes in the protein in response to pH or substrate ions. The first change is induced by a rise in pH from 6 to 7 and marks the transition from the inactive state to the pH-activated state. pH activation, which precedes the ion-induced conformational change, is accompanied by an overall expansion of the NhaA monomer and a local ordering of the N-terminus. The second conformational change is induced by the substrate ions Na+ and Li+ at pH above 7 and involves a 7-A displacement of helix IVp. This movement would cause a charge imbalance at the ion-binding site that may trigger the release of the substrate ion and open a periplasmic exit channel.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1089-8638
pubmed:author
pubmed:issnType
Electronic
pubmed:day
8
pubmed:volume
388
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
659-72
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Conformations of NhaA, the Na+/H+ exchanger from Escherichia coli, in the pH-activated and ion-translocating states.
pubmed:affiliation
Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, Frankfurt am Main, Germany.
pubmed:publicationType
Journal Article, Corrected and Republished Article