Chemical versus mechanical perturbations on the protonation state of arginine in complex lipid membranes: insights from microscopic pKa calculations.
Chemical versus mechanical perturbations on the protonation state of arginine in complex lipid membranes: insights from microscopic pKa calculations.
复制标题
复杂脂质膜中精氨酸质子化状态的化学扰动与机械扰动：微观 pKa 计算的见解。
DOI：
10.1016/j.bpj.2010.06.048
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发表时间：
2010
影响因子：
3.4
通讯作者：
Cui,Qiang
中科院分区：
文献类型：
--
作者：
Yoo,Jejoong;Cui,Qiang
Charged amino acids such as Arginine play important roles in many membrane-mediated biological processes such as voltage gating of ion channels and membrane translocation of cell penetration peptides. It is well established that local membrane deformation and formation of water defects are crucial to the stabilization of charged species in contact with the membrane, which suggests that mechanical properties of the membrane are relevant although a clear connection has not been established. As a quantitative measure, we study how changes in the composition and therefore mechanical properties of a lipid bilayer influence the pKaof Arg in the membrane center using free energy simulations. Compared to previous studies in a single-component lipid bilayer containing saturated lipids or lipids with a modest degree of unsaturation, substantially larger pKashifts are observed in the presence of highly unsaturated lipid tails and cholesterol. Moreover, the underlying molecular mechanisms for the pKaperturbation are distinct in different systems, with the unsaturated lipid tails mainly destabilizing the charged state of Arg and the cholesterol stabilizing the neutral state of Arg. The observed behaviors in both cases are at odds with predictions based on mechanical considerations at a mesoscopic level—highlighting that, while mechanical considerations are useful for stimulating hypothesis, their applicability to dissecting phenomena at the molecular-length scale is rather limited.
