Water pathways in the bacteriorhodopsin proton pump.
Water pathways in the bacteriorhodopsin proton pump.
复制标题
细菌视紫红质质子泵中的水通路。
DOI：
10.1007/s00232-010-9329-3
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Smith,JeremyC
中科院分区：
文献类型：
--
作者：
Bondar,Ana-Nicoleta;Fischer,Stefan;Smith,JeremyC
内部水分子在光驱动细菌视紫红质质子泵的功能中起着关键作用。特别重要的是，在质子泵循环中，关键水分子w402能否从细胞外迁移到视网膜席夫碱的细胞质侧。本文通过经典力学计算和量子力学/分子力学结合的反应路径计算，探讨了影响w402重定位的途径和能量因素。w402与带负电荷的Asp85和Asp212之间的氢键在很大程度上反对水分子的重新定位。相比之下，w402与Schiff碱和Thr89的氢键以及视网膜多烯链的解扭的有利贡献降低了水迁移的能量成本。相互竞争的贡献之间的微妙平衡是需要高度精确的计算和结构信息的基础。
Internal water molecules play key roles in the functioning of the light-driven bacteriorhodopsin proton pump. Of particular importance is whether during the proton-pumping cycle the critical water molecule w402 can relocate from the extracellular to the cytoplasmic side of the retinal Schiff base. Here, classical mechanical and combined quantum mechanical/molecular mechanical reaction path computations are performed to investigate pathways and energetic factors influencing w402 relocation. Hydrogen bonding between w402 and the negatively charged Asp85 and Asp212 largely opposes repositioning of the water molecule. In contrast, favorable contributions from hydrogen bonding of w402 with the Schiff base and Thr89 and from the untwisting of the retinal polyene chain lower the energetic cost for water relocation. The delicate balance between the competing contributions underlies the need for highly accurate calculations and structural information.