Data/hora: 05/06/2024 16:11:41

Provedor de dados: | 48
País: | Chile
Título: | The interaction of ryanoids with individual ryanodine receptor channels
Autores: | WILLIAMS,ALAN J; TANNA,BHAVNA.
Data: | 2004-01-01
Ano: | 2004
Palavras-chave: | Calcium; Ca2+-release channel; Sarcoplasmic reticulum; Ryanodine; Single channel.
Resumo: | Ryanodine binds with high affinity and specificity to a class of Ca2+-release channels known as ryanodine receptors (RyR). The interaction with RyR results in a dramatic alteration in function with open probability (Po) increasing markedly and rates of ion translocation modified. We have investigated the features of ryanodine that govern the interaction of the ligand with RyR and the mechanisms underlying the subsequent alterations in function by monitoring the effects of congeners and derivatives of ryanodine (ryanoids) on individual RyR2 channels. While the interaction of all tested ryanoids results in an increased Po, the amplitude of the modified conductance state depends upon the structure of the ryanoid. We propose that different rates of cation translocation observed in the various RyR-ryanoid complexes represent different conformations of the channel stabilized by specific conformers of the ligand. On the time scale of a single channel experiment ryanodine binds irreversibly to the channel. However, alterations in structure yield some ryanoids with dissociation rate constants orders of magnitude greater than ryanodine. The probability of occurrence of the RyR-ryanoid complex is sensitive to trans-membrane voltage, with the vast majority of the influence of potential arising from a voltage-driven alteration in the affinity of the ryanoid-binding site.
Tipo: | Journal article
Idioma: | Inglês
Identificador: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000400006
Editor: | Sociedad de Biología de Chile
Formato: | text/html
Fonte: | Biological Research  v.37 n.4 2004