DESTABILIZATION OF AN ALPHA-HELIX-BUNDLE PROTEIN BY HELIX DIPOLES
DESTABILIZATION OF AN ALPHA-HELIX-BUNDLE PROTEIN BY HELIX DIPOLES
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DOI：
10.1073/pnas.86.5.1524
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发表时间：
1989-03-01
影响因子：
11.1
通讯作者：
HONIG, B
中科院分区：
文献类型：
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作者：
GILSON, MK;HONIG, B
使用有限差分泊松-玻尔兹曼方法来计算组装四个α- Themiste dyscritum hemerythrin的螺旋形成蛋白质的观察到的反平行螺旋束。计算占每个螺旋偶极子与高介电溶剂的相互作用，以及成对的相互作用的偶极子彼此。我们发现，组装的静电工作主要是由偶极溶剂相互作用的不利变化，而不是由有利的反平行螺旋之间的相互作用。此外，在Hemerythrin中观察到的螺旋排列与至少一种其他可能的螺旋排列之间的静电能差小于1 kT。这些结果表明，螺旋偶极子实际上使螺旋束不稳定，并且在产生所观察到的束几何形状中起很小或没有作用。
The finite difference Poisson-Boltzmann method is used to calculate the electrostatic work of assembling the four .alpha.-helices of Themiste dyscritum hemerythrin to form the protein''s observed antiparallel helical bundle. The calculations account for the interaction of each helix dipole with the high-dielectric solvent as well as for pairwise interactions of the dipoles with each other. We find that the electrostatic work of assembly is dominated by unfavorable changes in dipole-solvent interactions rather than by favorable interactions between antiparallel helices. Furthermore, the electrostatic energy difference between the observed arrangement of helices in hemerythrin and at least one other possible helical arrangement is less than 1 kT. These results suggest that the helix dipole actually destabilizes the helical bundle and that it plays little or no role in producing the observed bundle geometry.