Protonation of the acidic residues in the transmembrane cation-binding sites of the ca(2+) pump.
Protonation of the acidic residues in the transmembrane cation-binding sites of the ca(2+) pump.
复制标题
DOI：
10.1021/ja0427505
复制
发表时间：
2005-04
影响因子：
15
通讯作者：
Y. Sugita;N. Miyashita;M. Ikeguchi;A. Kidera;C. Toyoshima
中科院分区：
文献类型：
--
作者：
Y. Sugita;N. Miyashita;M. Ikeguchi;A. Kidera;C. Toyoshima
采用连续介质静电场计算和全原子分子动力学模拟方法，研究了肌浆网Ca ~（2+）ATP酶Ca ~（2+）结合位点周围酸性残基的电离状态。这两种方法一致表明，Glu 58和Glu 908质子化在中性pH值。的Ca 2+的协调和由Glu 58和Glu 908的质子化形成的H-键是稳定的MD模拟，而H-键被破坏和Ca 2+的协调几何形状被严重改变，在另一个模拟处理这些残基未质子化。结果清楚地表明，由Glu 58和Glu 908质子化形成的H-键为Ca ~（2+）ATP酶的Ca ~（2+）结合位点提供额外的稳定性。
The ionization states of the acidic residues around the Ca2+-binding sites of sarcoplasmic reticulum Ca2+ ATPase are studied by continuum electrostatic calculations and all-atom molecular dynamics simulations with explicit solvent and phospholipids. The two methods consistently indicate that Glu58 and Glu908 are protonated at neutral pH. The Ca2+ coordination and the H-bonds formed by the protonation of Glu58 and Glu908 are stable in an MD simulation, whereas the H-bonds are disrupted and the Ca2+ coordination geometry is severely altered in another simulation treating these residues unprotonated. The results clearly indicate that the H-bonds formed by protonation of Glu58 and Glu908 provide extra stability for the Ca2+-binding sites of Ca2+ ATPase.