Interaction between tyrosine(Z) and substrate water in active photosystem II
文献类型：期刊论文
| 作者 | Zhang, Chunxi |
| 刊名 | BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
 |
| 出版日期 | 2006-07-01 |
| 卷号 | 1757期号:7页码:781-786 |
| 关键词 | Photosystem Ii Tyrosine z Epr Substrate Water Ph Dependence Dft Calculation |
| ISSN号 | 0005-2728 |
| DOI | 10.1016/j.bbabio.2006.05.036 |
| 英文摘要 | In the field of photosynthetic water oxidation it has been under debate whether Tyrosine(Z) (Tyr(Z)) acts as a hydrogen or an electron acceptor from water. In the former concept, direct contact of Tyr(Z) with substrate water has been assumed. However, there is no direct evidence for the interaction between Tyr(Z) and substrate water in active Photosystem II (PSII), instead most experiments have been performed on inhibited PSII. Here, this problem is tackled in active PSII by combining low temperature EPR measurements and quantum chemistry calculations. EPR measurements observed that the maximum yield of Tyr(Z) oxidation at cryogenic temperature in the So and S, states was around neutral pH and was essentially pH-independent. The yield of Tyr(Z) oxidation decreased at acidic and alkaline pH, with pKs at 4.7-4.9 and 7.7, respectively. The observed pH-dependent parts at low and high values of pH can be explained as due to sample inactivation, rather than active PSII. The reduction kinetics of Tyr(Z) in the S-0 and S-1 states were pH independent at pH range from 4.5 to 8. Therefore, the change of the pH in bulk solution probably has no effect on the Tyr(Z) oxidation and Tyr(Z) reduction at cryogenic temperature in the S-0 and S-1 states of the active PSII. Theoretical calculations indicate that Tyr(Z) becomes more difficult to oxidize when a H2O molecule interacts directly with it. It is suggested that Tyr(Z) is probably located in a hydrophobic environment with no direct interaction with the substrate H2O in active PSII. These results provide new insights on the function and mechanism of water oxidation in PSII. (c) 2006 Elsevier B.V. All rights reserved. |
| 语种 | 英语 |
| WOS记录号 | WOS:000240053700007 |
| 出版者 | ELSEVIER SCIENCE BV |
| 源URL | [http://ir.iccas.ac.cn/handle/121111/58525]  |
| 专题 | 中国科学院化学研究所 |
| 通讯作者 | Zhang, Chunxi |
| 作者单位 | 1.Chinese Acad Sci, Inst Chem, Ctr Mol Sci, Lab Photochem, Beijing 100080, Peoples R China 2.CEA Saclay, CNRS, URA 2096, Serv Bioenerget,Dept Biol Joliot Curie, F-91191 Gif Sur Yvette, France |
| 推荐引用方式 GB/T 7714 | Zhang, Chunxi. Interaction between tyrosine(Z) and substrate water in active photosystem II[J]. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS,2006,1757(7):781-786. |
| APA | Zhang, Chunxi.(2006).Interaction between tyrosine(Z) and substrate water in active photosystem II.BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS,1757(7),781-786. |
| MLA | Zhang, Chunxi."Interaction between tyrosine(Z) and substrate water in active photosystem II".BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1757.7(2006):781-786. |
入库方式： OAI收割
来源：化学研究所
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