Low-barrier hydrogen bond plays key role in active photosystem II - A new model for photosynthetic water oxidation
文献类型：期刊论文
| 作者 | Zhang, Chunxi |
| 刊名 | BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
 |
| 出版日期 | 2007-06-01 |
| 卷号 | 1767期号:6页码:493-499 |
| 关键词 | Photosystem Ii Tyrosinez His190 Mn-cluster Low-barrier Hydrogen Bond Proton And Electron Transfer |
| ISSN号 | 0005-2728 |
| DOI | 10.1016/j.bbabio.2006.12.008 |
| 英文摘要 | The function and mechanism of Tyr(Z) in active photosystem II (PSII) is one of the long-standing issues in the study of photosynthetic water oxidation. Based on recent investigations on active PSII and theoretical studies, a new model is proposed, in which D1-His 190 acts as a bridge, to form a low-barrier hydrogen bond (LBHB) with Tyr(z,) and a coordination bond to Mn or Ca ion of the Mn-cluster. Accordingly, this new model differs from previous proposals concerning the mechanism of Tyrz function in two aspects. First, the LBHB plays a key role to decrease the activation energy for Tyr(z) oxidation and Tyr(Z) reduction during photosynthetic water oxidation. Upon the oxidation of Tyr(z), the hydrogen bond between Tyr(z) and His190 changes from a LBHB to a weak hydrogen bond, and vice versa upon Tyr(z) reduction. In both stages, the electron transfer and proton transfer are coupled. Second, the positive charge formed after Tyr(z) oxidation may play an important role for water oxidation. It can be delocalized on the Mn-cluster, thus helps to accelerate the proton release from substrate water on Mn-cluster. This model is well reconciled with observations of the S-state dependence of Tyr(z) oxidation and Tyr(z) reduction, proton release, isotopic effect and recent EPR experiments. Moreover, the difference between Tyr(z) and Tyr(D) in active PSII can also be readily rationalized. The His190 binding to the Mn-cluster predicted in this model is contradictions to the recent structure data, however, it has been aware that the crystal structure of the Mn-cluster and its environment are significantly modified by X-ray due to radiation damage and are different from that in active PSII. It is suggested that the His190 may be protonated during the radiation damage, which leads to the loss of its binding to Mn-cluster and the strong hydrogen bond with Tyrz. This type of change arising from radiation damage has been confirmed in other enzyme systems. (c) 2007 Elsevier B.V. All rights reserved. |
| 语种 | 英语 |
| WOS记录号 | WOS:000247650500011 |
| 出版者 | ELSEVIER SCIENCE BV |
| 源URL | [http://ir.iccas.ac.cn/handle/121111/60383]  |
| 专题 | 中国科学院化学研究所 |
| 通讯作者 | Zhang, Chunxi |
| 作者单位 | Chinese Acad Sci, Inst Chem, Ctr Mol Sci, Lab Photochem, Beijing 100080, Peoples R China |
| 推荐引用方式 GB/T 7714 | Zhang, Chunxi. Low-barrier hydrogen bond plays key role in active photosystem II - A new model for photosynthetic water oxidation[J]. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS,2007,1767(6):493-499. |
| APA | Zhang, Chunxi.(2007).Low-barrier hydrogen bond plays key role in active photosystem II - A new model for photosynthetic water oxidation.BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS,1767(6),493-499. |
| MLA | Zhang, Chunxi."Low-barrier hydrogen bond plays key role in active photosystem II - A new model for photosynthetic water oxidation".BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1767.6(2007):493-499. |
入库方式： OAI收割
来源：化学研究所
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