Linked Life Data

19210955

Source:http://linkedlifedata.com/resource/pubmed/id/19210955

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2009-2-27
pubmed:abstractText
We examine the hypotheses that the Streptomyces lividans potassium channel KcsA is gated at neutral pH by the electrochemical potential, and that its selectivity and conductance are governed at the cytoplasmic face by interactions between the KcsA polypeptides and a core molecule of inorganic polyphosphate (polyP). The four polypeptides of KcsA are postulated to surround the end unit of the polyP molecule with a collar of eight arginines, thereby modulating the negative charge of the polyP end unit and increasing its preference for binding monovalent cations. Here we show that KcsA channels can be activated in planar lipid bilayers at pH 7.4 by the chemical potential alone. Moreover, one or both of the C-terminal arginines are replaced with residues of progressively lower basicity-lysine, histidine, valine, asparagine-and the effects of these mutations on conductance and selectivity for K(+) over Mg(2+) is tested in planar bilayers as a function of Mg(2+) concentration and pH. As the basicity of the C-terminal residues decreases, Mg(2+) block increases, and Mg(2+) becomes permeant when medium pH is greater than the pI of the C-terminal residues. The results uphold the premise that polyP and the C-terminal arginines are decisive elements in KcsA channel regulation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:volume
1788
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
608-14
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Role of polyphosphate in regulation of the Streptomyces lividans KcsA channel.
pubmed:affiliation
Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.