蓝藻cNII调控铁依赖性NDH-CET的分子机制研究

Cyclic electron transport mediated by NDH-1 (NDH-CET) plays an important role in resisting iron stress. However, the regulation mechanism of iron-dependent NDH-CET remains elusive. Recently, we identified a cNII1 unknown protein that contains an iron-chelating domain. Under conditions of iron deficiency, absence of cNII1 resulted in impairment of NDH-CET. Furthermore, cNII1 interacts exclusively with NdhI, a conserved NDH-1 subunit carrying two iron-sulfur clusters. Thus, we will first reveal the effects of cNII1 on the amounts of NdhI and NDH-1 assembly intermediate in the cytoplasm and of integrated NDH-1 in the thylakoid membrane. Further, we will clarify the molecular mechanism how cNII1 regulates the iron-dependent NDH-CET. Finally, to improve the molecular regulation mechanism for the iron-dependent NDH-CET and construct a relatively improved regulatory network of iron-dependent NDH-CET, we will screen, isolate and identify these novel cNII using the strategies of molecular biology, physiology and biochemistry. The clarification of such regulatory network will certainly increase our understanding the physiological function of cyanobacterial NDH-1 under conditions of iron deficiency and provide an important theory reference for understanding the physiological function of chloroplast NDH-1 in higher plants.

NDH-1介导的环式电子传递（NDH-CET）在蓝藻抵御铁胁迫中扮演着重要的角色，但人们对调控铁依赖性NDH-CET的分子机制尚不了解。最近，我们鉴定到一个具有铁螯合活性的未知蛋白——cNII1；在缺铁条件下，它的缺失导致NDH-CET受损，并且这一铁螯合蛋白专一地与NDH-1铁硫亚基NdhI存在互作。因此，本项目将首先揭示cNII1与NdhI，NDH-1组装中间体，以及完整NDH-1复合体之间的相互关系，并进一步阐明这一铁螯合蛋白调控铁依赖性NDH-CET的分子机制。然后，通过分子生物学、生理和生化等手段，筛选、分离和鉴定出新的cNII，并揭示它们调控铁依赖性NDH-CET的分子机制；最终构建一个相对完善的铁依赖性NDH-CET调控网络。这一调控网络的构建必将增进人们对铁胁迫条件下蓝藻NDH-1重要生理功能的理解，也为理解高等植物叶绿体NDH-1生理功能提供重要的理论参考。

NDH-1介导的环式电子传递（NDH-CET）在蓝藻抵御铁胁迫中扮演着重要的角色，但人们对调控铁依赖性NDH-CET的分子机制尚不了解。通过本项目的实施，我们发现了一条铁依赖的NDH-CET途径和3个cNII蛋白，并阐明这3个蛋白从不同层面上调控这一铁依赖性途径，由此勾勒出了一个铁依赖性环式电子传递调控网络。相关的研究成果总结成7篇标注SCI学术论文发表在国际专业期刊上，其中，一区SCI论文4篇，二区SCI论文3篇（JCR分区）和1本标注的学术专著；同时组建了一支研究蓝藻光合NDH-1的年轻队伍。这一调控网络的构建必将增进人们对铁胁迫条件下蓝藻NDH-1重要生理功能的理解，也为理解高等植物叶绿体NDH-1生理功能提供重要的理论参考。