Human 5-HT3A -- Gln 88
|Rat Equivalent||Gln 87|
|Mouse Equivalent||Gln 93||Ala||Q93A|
Nine residues (Thr 86, Thr 87, Tyr 88, Ile 89, Tyr 91, Arg 92, Gln 93, Tyr 94, Trp 95) were mutated individually to alanine (alanine scanning mutagenesis). [3H]granisetron, curare, and serotonin as the ligands to examine the properites of the 5-HT3 binding site.
W90F was analyzed instead of W90A, and it proved to be the only one that significantly affected the interaction of curare with the receptor. R92A was the only substitution that altered the affinity of the agonist serotonin. W90F, R92A, and Y94A all reduced the affinity of [3H]granisetron. The periodicity of the effect suggests the participation of a beta-strand.
Yan D, Schulte MK, Bloom KE, White MM (1999) Structural Features of the Ligand-binding Domain of the Serotonin 5HT3 Receptor. The Journal of Biological Chemistry 274 (9): 5537-5541
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