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Figure 4.
Figure 4. The Anion Binding Site Is Located in the Ligand
Binding Core
(A) Cartoon of a kainate receptor subunit
illustrating creation of the ATD(−) deletion construct and the
block of desensitization when disulfide bond crosslinks are
introduced in a ligand binding domain dimer assembly.
(B)
Anion modulation of glutamate-evoked peak current amplitude,
relative to the response in Cl^− (left) and desensitization
rate (right), is similar in wild-type GluR6 and the ATD(−)
construct. Data points show the mean ± SEM for at least
five separate observations.
(C) Nondesensitizing kainate
receptors formed by disulfide crosslinking the ligand binding
domains of GluR6 are insensitive to modulation by anions. The
bar plots show peak amplitude and percentage of desensitization
for responses to glutamate recorded from the GluR6 Y490C L752C
crosslinked mutant with fluoride, chloride, iodide, nitrate, or
methanesulfonate as the extracellular anion. Data points show
the mean ± SEM for at least five separate observations
per condition.
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