Radiolytic Mapping of Solvent-Contact Surfaces in Photosystem II of Higher Plants
Radiolytic Mapping of Solvent-Contact Surfaces in Photosystem II of Higher Plants
复制标题
高等植物光系统 II 中溶剂接触表面的辐射分解图
DOI：
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发表时间：
2013
影响因子：
4.8
通讯作者：
T. M. Bricker
中科院分区：
文献类型：
--
作者：
L. K. Frankel;L. Sallans;H. Bellamy;J. Goettert;P. Limbach;T. M. Bricker
背景：基质水必须到达光系统II中埋藏的Mn4O5Ca簇。结果：辐解产生的OH·修饰了埋藏的氨基酸残基。这些被映射到PS II晶体结构上。结论：确定了两组氧化残基，它们形成推定的Mn4O5Ca簇合物的途径。意义：水和氧通道的识别对于我们理解光系统II的功能至关重要。光系统II使用水作为酶底物。据推测，这种水被引导到活性位点，通过水通道，导致从表面的蛋白质复合物的Mn4O5Ca金属簇的水氧化。通过同步加速器辐射对水进行辐解会产生修饰氨基酸残基的OH·，并且是识别与水接触的蛋白质区域的强大技术。在这项研究中，我们已经使用这种技术来氧化修饰埋在高等植物光系统II膜的氨基酸残基。然后使用傅立叶变换离子回旋共振质谱法来鉴定位于几个核心光系统II亚基（D1、D2、CP 43和CP 47）中的这些氧化的氨基酸残基。虽然，正如预期的那样，大多数已鉴定的氧化残基（约75%）位于复合物的溶剂暴露表面上，但这些蛋白质上的一些掩埋残基也被修饰。这些残基形成的基团似乎导致从表面的复杂的Mn4O5Ca集群。这些残基可能与光系统中假定的水通道接触。这些结果进行了讨论的背景下，大量的计算研究，确定了假定的水通道光系统II。
Background: Substrate water must reach the buried Mn4O5Ca cluster in Photosystem II. Results: OH• produced by radiolysis modified buried amino acid residues. These were mapped onto the PS II crystal structure. Conclusion: Two groups of oxidized residues were identified which form putative pathways to the Mn4O5Ca cluster. Significance: Identification of water and oxygen channels is crucial for our understanding of Photosystem II function. Photosystem II uses water as an enzymatic substrate. It has been hypothesized that this water is vectored to the active site for water oxidation via water channels that lead from the surface of the protein complex to the Mn4O5Ca metal cluster. The radiolysis of water by synchrotron radiation produces amino acid residue-modifying OH• and is a powerful technique to identify regions of proteins that are in contact with water. In this study, we have used this technique to oxidatively modify buried amino acid residues in higher plant Photosystem II membranes. Fourier transform ion cyclotron resonance mass spectrometry was then used to identify these oxidized amino acid residues that were located in several core Photosystem II subunits (D1, D2, CP43, and CP47). While, as expected, the majority of the identified oxidized residues (≈75%) are located on the solvent-exposed surface of the complex, a number of buried residues on these proteins were also modified. These residues form groups which appear to lead from the surface of the complex to the Mn4O5Ca cluster. These residues may be in contact with putative water channels in the photosystem. These results are discussed within the context of a number of largely computational studies that have identified putative water channels in Photosystem II.
影响因子：
5.6
作者：
Lario, PI;Sampson, N;Vrielink, A
通讯作者：
Vrielink, A
时间分辨振动光谱检测光合作用释氧循环中基于蛋白质的中间体。
DOI：
10.1073/pnas.0600216103
发表时间：
2006
影响因子：
11.1
作者：
Barry,BridgetteA;Cooper,IanB;DeRiso,Antonio;Brewer,ScottH;Vu,DungM;Dyer,RBrian
通讯作者：
Dyer,RBrian