Linked Life Data

1730708

Source:http://linkedlifedata.com/resource/pubmed/id/1730708

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1992-2-18
pubmed:abstractText
A peptidyl inhibitor of the high conductance Ca(2+)-activated K+ channels (KCa) has been purified to homogeneity from the venom of the scorpion Androctonus mauretanicus mauretanicus. The peptide has been named kaliotoxin (KTX). It is a single 4-kDa polypeptide chain. Its complete amino acid sequence has been determined. KTX displays sequence homology with other scorpion-derived inhibitors of Ca(2+)-activated or voltage-gated K+ channels: 44% homology with charybdotoxin (CTX), 52% with noxiustoxin (NTX), and 44% with iberiotoxin (IbTX). Electrophysiological experiments performed in identified nerve cells from the mollusc Helix pomatia showed that KTX specifically suppressed the whole cell Ca(2+)-activated K+ current. KTX had no detectable effects on voltage-gated K+ current (delayed rectifier and fast transient A current) or on L-type Ca2+ currents. KTX interacts in a one-to-one way with KCa channels with a Kd of 20 nM. Single channel experiments were performed on high conductance KCa channels excised from the above Helix neurons and from rabbit coeliac ganglia sympathetic neurons. KTX acted exclusively at the outer face of the channel. KTX applied on excised outside-out KCa channels induced a transient period of fast-flicker block followed by a persistent channel blockade. The KTX-induced block was not voltage-dependent which suggests differences in the blockade of KCa channels by KTX and by CTX. Comparison of KTX and CTX sequences leads to the identification of a short amino acid sequence (26-33) which may be implicated in the toxin-channel interaction. KTX therefore appears to be a useful tool for elucidating the molecular pharmacology of the high conductance Ca(2+)-activated K+ channel.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
267
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1640-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:1730708-Amino Acid Sequence, pubmed-meshheading:1730708-Amino Acids, pubmed-meshheading:1730708-Animals, pubmed-meshheading:1730708-Calcium, pubmed-meshheading:1730708-Cells, Cultured, pubmed-meshheading:1730708-Chromatography, High Pressure Liquid, pubmed-meshheading:1730708-Egtazic Acid, pubmed-meshheading:1730708-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:1730708-Helix (Snails), pubmed-meshheading:1730708-Male, pubmed-meshheading:1730708-Membrane Potentials, pubmed-meshheading:1730708-Mice, pubmed-meshheading:1730708-Mice, Inbred C57BL, pubmed-meshheading:1730708-Molecular Sequence Data, pubmed-meshheading:1730708-Neurons, pubmed-meshheading:1730708-Peptide Mapping, pubmed-meshheading:1730708-Potassium Channels, pubmed-meshheading:1730708-Protein Conformation, pubmed-meshheading:1730708-Scorpion Venoms, pubmed-meshheading:1730708-Sequence Homology, Nucleic Acid, pubmed-meshheading:1730708-Tetraethylammonium, pubmed-meshheading:1730708-Tetraethylammonium Compounds
pubmed:year
1992
pubmed:articleTitle
Kaliotoxin, a novel peptidyl inhibitor of neuronal BK-type Ca(2+)-activated K+ channels characterized from Androctonus mauretanicus mauretanicus venom.
pubmed:affiliation
Laboratoire de Neurobiologie, Centre National de la Recherche Scientifique, Marseille, France.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't