Fig. 7. Selective arylation of hyperreactive thiols by CPM disables the transmembrane redox sensor. Recording of channel activity starts from undefined transmembrane redox potential in the presence of 7 n-M Ca2+ (bar 1, both panels). In left panel [GSH]/[GSSG] = 3 mtf/1 mM (giving -180 mV redox potential) is symmetrically applied into both cis and trans (bar 2); subsequent addition of GSH 9.72 mM introduces —210 mV into cis (bar 3); extensive perfusion of both cis and trans is performed to remove transmembrane redox potential (bar 4) followed by reestablished with [GSH]/[GSSG] = 3 mM/1 mM to both cis and trans (bar 5). In right panel [GSH]/[GSSG] of 0.95 mM/0.10 mM, and 4.0 mM/1.79 mM are introduced into the cytoplasmic chamber for —180 mV in cis and trans, respectively (bar 2). Further reduction of cis to -220 mV is made by addition of [GSH]/[GSSG] to 4.55 m/W/0.1 mM (bar 3). After perfusion of both chambers to removed GSH and GSSG, CPM (20 nM) is introduced into cis for 2 min before being terminated by perfusion (bar 4, marked with an asterick). Reinstillation of [GSH]/[GSSG] is made with 0.95 mM/0.10 mM and 4.0 mM/1.79 mM in cis and trans, respectively (symmetrical — 180 mV; bar 5).

cis , trans

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