... affectthe activity [10,11,19], mutagenesis at this region inLqh3 had no effect (Table 1), suggesting that this structural motif was not involved in direct contact with 1.00.80.60.40.28.07.57.06.5pH0.0Lqh3E10Y-E63R1.00.80.60.40.20.0[Toxin] ... Whereas substitutions ofHis15, His36 and His43 did not reduce Lqh3 sensitiv-ity to pH, substitutions of His66 had a clear impact with the utmost decrease obtained with H66R(Table 3). Unexpectedly, ... Lqh3sensitivity to pH is associated with some later stage inthe binding process to the channel. This is corrobor-ated by previous binding studies, which demonstratedthat Lqh3 association rate did not change...