Linked Life Data

6313052

Source:http://linkedlifedata.com/resource/pubmed/id/6313052

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1983-12-17
pubmed:abstractText
Protein P, an anion-specific channel-forming protein from the outer membrane of Pseudomonas aeruginosa was chemically modified by acetylation and syccinylation of its accessible amino groups. The chemically modified protein retained its ability to form oligomers on sodium dodecyl sulfate polyacrylamide gels, whereas only the acetylated protein formed channels in reconstitution experiments with lipid bilayers. Acetylated protein P demonstrated a substantially reduced mean single channel conductance (25 pS at 1 M KCl) compared to the native protein P channels (250 pS at 1 M KCl) when reconstituted into black lipid bilayer membranes. The homogeneous size distribution of single-channel conductances suggested that all of the protein P molecules had been acetylated. Zero-current potential measurements demonstrated that the acetylated protein P channel was only weakly selective for anions and allowed the permeation of cations, in contrast to the native protein P channels, which were more than 100-fold selective for anions over cations. The dependence of conductance on salt concentration was changed upon acetylation, in that acetylated protein P demonstrated a linear concentration-conductance relationship, whereas native protein P channels became saturated at high salt concentrations. These data strongly suggested that the basis of anion selectivity for native protein P channels is fixed amino groups. In agreement with this, we could demonstrate a 2.5-fold decrease in single-channel conductance between pH 7 and pH 9, between which pH values the epsilon-amino groups of amino acids would start to become deprotonated. Two alternative schemes for the topography of the protein P channel and localization of the fixed amino groups are presented and discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
735
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
137-44
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Modification of the conductance, selectivity and concentration-dependent saturation of Pseudomonas aeruginosa protein P channels by chemical acetylation.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't