Linked Life Data

11404401

Source:http://linkedlifedata.com/resource/pubmed/id/11404401

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2001-6-13
pubmed:abstractText
In AMPA receptor channels, a single amino acid residue (Q/R site) of the M2 segment controls permeation of calcium ions, single-channel conductance, blockade by intracellular polyamines, and permeation of anions. The structural environment of the Q/R site and its positioning with regard to a narrow constriction were probed with the accessibility of substituted cysteines to positively and negatively charged methanethiosulfonate reagents, applied from the extracellular and cytoplasmic sides of the channel. The accessibility patterns confirm that the M2 segment forms a pore loop with the Q/R site positioned at the tip of the loop (position 0) facing the extracellular vestibule. Cytoplasmically accessible residues on the N- and C-terminal sides of position 0 form the ascending alpha-helical (-8 to -1) and descending random coil (+1 to +6) components of the loop, respectively. Substitution of a glycine residue at position +2 with alanine strongly decreased the permeability of organic cations, indicating that position +2 contributes to the narrow constriction. The anionic 2-sulfonatoethyl-methanethiosufonate reacted with a cysteine at position 0 only from the external side and with cysteines at positions +1 to +4 only from the cytoplasmic side. These results suggest that charge selectivity occurs external to the constriction (+2) and possibly involves interactions of ions with the negative electrostatic potential created by the dipole of the alpha-helix formed by the ascending limb of the loop.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4162-72
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11404401-Amino Acid Substitution, pubmed-meshheading:11404401-Animals, pubmed-meshheading:11404401-Calcium, pubmed-meshheading:11404401-Cysteine, pubmed-meshheading:11404401-Cytoplasm, pubmed-meshheading:11404401-Dose-Response Relationship, Drug, pubmed-meshheading:11404401-Ethyl Methanesulfonate, pubmed-meshheading:11404401-Glutamic Acid, pubmed-meshheading:11404401-Ion Channel Gating, pubmed-meshheading:11404401-Kainic Acid, pubmed-meshheading:11404401-Kinetics, pubmed-meshheading:11404401-Membrane Potentials, pubmed-meshheading:11404401-Mesylates, pubmed-meshheading:11404401-Microinjections, pubmed-meshheading:11404401-Mutagenesis, Site-Directed, pubmed-meshheading:11404401-Oocytes, pubmed-meshheading:11404401-Patch-Clamp Techniques, pubmed-meshheading:11404401-Permeability, pubmed-meshheading:11404401-Receptors, AMPA, pubmed-meshheading:11404401-Structure-Activity Relationship, pubmed-meshheading:11404401-Sulfhydryl Reagents, pubmed-meshheading:11404401-Xenopus laevis
pubmed:year
2001
pubmed:articleTitle
Channel-lining residues of the AMPA receptor M2 segment: structural environment of the Q/R site and identification of the selectivity filter.
pubmed:affiliation
Abteilung Molekulare Neurobiologie, Abteilung Zellphysiologie, Max-Planck Institut für Medizinische Forschung, 69120 Heidelberg, Germany. kuner@mpimf-heidelberg.mpg.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't