Warning: Undefined variable $zfal in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 525
Deprecated: str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 525
Warning: Undefined variable $sterm in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 530
Warning: Undefined variable $sterm in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 531
 
English Wikipedia
Nephropedia Template TP (
Twit Text
DeepDyve
Pubget Overpricing |  
lüll
Outer pore architecture of a Ca2+-selective TRP channel Voets T; Janssens A; Droogmans G; Nilius BJ Biol Chem 2004[Apr]; 279 (15): 15223-30The TRP superfamily forms a functionally important class of cation channels related to the product of the Drosophila trp gene. TRP channels display an unusual diversity in activation mechanisms and permeation properties, but the basis of this diversity is unknown, as the structure of these channels has not been studied in detail. To obtain insight in the pore architecture of TRPV6, a Ca(2+)-selective member of the TRPV subfamily, we probed the dimensions of its pore and determined pore-lining segments using cysteine-scanning mutagenesis. Based on the permeability of the channel to organic cations, we estimated a pore diameter of 5.4 A. Mutating Asp(541), a residue involved in high affinity Ca(2+) binding, altered the apparent pore diameter, indicating that this residue lines the narrowest part of the pore. Cysteines introduced in a region preceding Asp(541) displayed a cyclic pattern of reactivity to Ag(+) and cationic methylthio-sulfanate reagents, indicative of a pore helix. The anionic methanethiosulfonate ethylsulfonate showed only limited reactivity in this region, consistent with the presence of a cation-selective filter at the outer part of the pore helix. Based on these data and on homology with the bacterial KcsA channel, we present the first structural model of a TRP channel pore. We conclude that main structural features of the outer pore, namely a selectivity filter preceded by a pore helix, are conserved between K(+) channels and TRPV6. However, the selectivity filter of TRPV6 is wider than that of K(+) channels and lined by amino acid side chains rather than main chain carbonyls.|Amino Acid Sequence[MESH]|Animals[MESH]|Bacterial Proteins/chemistry[MESH]|Calcium Channels/*chemistry[MESH]|Calcium/*chemistry/metabolism[MESH]|Carbon/chemistry[MESH]|Cations[MESH]|Cell Line[MESH]|Cysteine/chemistry[MESH]|DNA/chemistry[MESH]|Drosophila[MESH]|Electrophysiology[MESH]|Ethyl Methanesulfonate/chemistry[MESH]|Genetic Vectors[MESH]|Humans[MESH]|Models, Molecular[MESH]|Molecular Sequence Data[MESH]|Mutagenesis, Site-Directed[MESH]|Mutation[MESH]|Potassium Channels/chemistry[MESH]|Potassium/chemistry[MESH]|Protein Conformation[MESH]|Silver/chemistry[MESH]|Sodium/chemistry[MESH]|TRPV Cation Channels[MESH]|Time Factors[MESH] |
