Linked Life Data

11347955

Source:http://linkedlifedata.com/resource/pubmed/id/11347955

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
2001-5-11
pubmed:abstractText
Several wasp venoms contain philanthotoxins (PhTXs) that act as noncompetitive inhibitors (NCIs) on cation-selective ion channels including the nicotinic acetylcholine receptor (nAChR). In the search for a ligand with high affinity and specificity for the nAChR we tested a series of newly developed PhTX analogues. Modulation of the structural elements of PhTXs can significantly influence their binding affinities. This approach resulted in the development of the photolabile compound MR44. In photoaffinity labelling studies 125I-MR44 was used to map the ligand-binding site at the Torpedo californica nAChR. Upon UV irradiation of the receptor-ligand complex, 125I-MR44 was mainly incorporated into the receptor alpha-subunit. Proteolytic mapping and microsequencing identified the site of 125I-MR44 cross-linking within the sequence alphaHis-186 to alphaLeu-199 that in its C-terminal region partially overlaps with the agonist-binding site. Since bound agonists had only minor influence on 125I-MR44 photocrosslinking, the site where the hydrophobic head group of 125I-MR44 binds must be located outside the zone that is sterically influenced by agonists bound at the nAChR. A possible site of interaction of 125I-MR44 would be the N-terminal region of the labelled sequence, in which aromatic amino-acid residues are accumulated. We suggest that the polyamine moiety of 125I-MR44 interacts with the high affinity non-competitive inhibitor site deep in the ion channel, while the aromatic ring of this compound binds in the vestibule of the nAChR to a hydrophobic region on the alpha-subunit that is located close to the agonist binding site.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0014-827X
pubmed:author
pubmed:issnType
Print
pubmed:volume
56
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
133-5
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:articleTitle
Binding of polyamine-containing toxins in the vestibule of the nicotinic acetylcholine receptor ion channel.
pubmed:affiliation
Institut für Chemie-Biochemie, Fachbereich Biologie, Chemie, Pharmazie (AG Neurochemie), Freie Universität Berlin, Germany. mgbixel@chemie.fu-berlin.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't