Linke Katrin, Ho Felix M
Photochemistry & Molecular Science, Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden.
Biochim Biophys Acta. 2014 Jan;1837(1):14-32. doi: 10.1016/j.bbabio.2013.08.003. Epub 2013 Aug 23.
Water is clearly important for the functioning of Photosystem II (PSII). Apart from being the very substrate that needs to be transported in this water oxidation enzyme, water is also vital for the transport of protons to and from the catalytic center as well as other important co-factors and key residues in the enzyme. The latest crystal structural data of PSII have enabled detailed analyses of the location and possible function of water molecules in the enzyme. Significant progress has also been made recently in the investigation of channels and pathways through the protein complex. Through these studies, the mechanistic significance of water for PSII is becoming increasingly clear. An overview and discussion of key aspects of the current research on water in PSII is presented here. The role of water in three other systems (aquaporin, bacteriorhodopsin and cytochrome P450) is also outlined to illustrate further points concerning the central significance that water can have, and potential applications of these ideas for continued research on PSII. It is advocated that water be seen as an integral part of the protein and far from a mere solvent.
水对于光系统II（PSII）的运作显然至关重要。除了作为这种水氧化酶中需要运输的底物外，水对于质子进出催化中心以及该酶中的其他重要辅助因子和关键残基的运输也至关重要。PSII的最新晶体结构数据使得能够对酶中水分子的位置和可能的功能进行详细分析。最近在研究穿过蛋白质复合物的通道和途径方面也取得了重大进展。通过这些研究，水对于PSII的机制意义越来越清晰。本文概述并讨论了当前关于PSII中水的研究的关键方面。还概述了水在其他三个系统（水通道蛋白、细菌视紫红质和细胞色素P450）中的作用，以进一步说明水可能具有的核心意义，以及这些观点在PSII持续研究中的潜在应用。有人主张应将水视为蛋白质不可或缺的一部分，而远非仅仅是一种溶剂。
