DIPOLES LOCALIZED AT HELIX TERMINI OF PROTEINS STABILIZE CHARGES
DIPOLES LOCALIZED AT HELIX TERMINI OF PROTEINS STABILIZE CHARGES
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DOI：
10.1073/pnas.88.5.2026
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发表时间：
1991-03-01
影响因子：
11.1
通讯作者：
WARSHEL, A
中科院分区：
文献类型：
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作者：
AQVIST, J;LUECKE, H;WARSHEL, A
与α-螺旋在蛋白质中的电荷稳定效应已被重新检查的微观计算没有任何先验假设的蛋白质的介电常数。 计算再现观察到的电荷稳定作用的螺旋在两个定义明确的测试情况下：组氨酸残基位于C-末端的螺旋在芽孢杆菌RNA酶和硫酸盐配体位于附近的N-末端的硫酸盐结合蛋白的螺旋。 他们还表明，螺旋电荷相互作用的有效介电常数比以前假设的要大得多，螺旋的稳定作用与螺旋宏偶极子无关，而是与几个局部偶极子主要局限于螺旋的第一圈。 据预测，在螺旋的一端的突变应该有非常小的影响，在相反的终端电荷的稳定。 它指出，相对短程效应的螺旋基本上是类似于其他情况下，其中本地化偶极子发挥关键作用，静电稳定。
The charge-stabilization effect associated with alpha-helices in proteins has been reexamined by microscopic calculations without any a priori assumptions about the dielectric constant of the protein. The calculations reproduce the observed charge stabilization effect of a helix in two well-defined test cases: a histidine residue situated at the C-terminal end of a helix in barnase and the sulfate ligand located near the N-terminal end of a helix of the sulfate-binding protein. They also show that the effective dielectric constant for helix-charge interactions is much larger than previously assumed and that the stabilizing effect of the helix is not associated with the helix macrodipole but rather with a few localized dipoles confined mostly to the first turn of the helix. It is predicted that mutations at one end of the helix should have very small effects on the stabilization of charges at the opposite terminus. It is pointed out that the relatively short-ranged effect of the helix is essentially similar to other cases in which localized dipoles play key roles in electrostatic stabilization.