MM-PBSA binding energy calculations for epibatidine and KAB-18 bound to hα4β2 and hα3β4 nAChR ECD models.

aBinding at agonist binding site 2 in the absence of antagonist.
bExperimental binding affinities calculated from data reported in [47], [48].
cDistance between the positively charged N atom in the bound epibatidine molecule and the backbone O atom of Trp148, quantifying epibatidine binding stability.
dCα-Cα distance between α191 and β58 at the binding interface, quantifying C loop closure.
eBoth compounds bound at agonist binding site 2.
Data averaged over 1.5 ns MD simulations with standard deviations in parentheses.

a. 无拮抗剂存在时，激动剂结合位点2处的配体结合情况
b. 实验结合亲和力由文献[47]、[48]报道的数据计算得到
c. 结合态依巴替丁（epibatidine）分子中带正电荷的氮原子与Trp148主链氧原子之间的距离，用于量化依巴替丁的结合稳定性
d. 结合界面处α191与β58的Cα-Cα距离，用于表征C环闭合程度
e. 两种化合物均结合于激动剂结合位点2处
数据为1.5 ns分子动力学（MD, Molecular Dynamics）模拟的平均值，标准差标注于括号内。