A Thylakoid Membrane Protein Functions Synergistically with GUN5 in Chlorophyll Biosynthesis.
A Thylakoid Membrane Protein Functions Synergistically with GUN5 in Chlorophyll Biosynthesis.
复制标题
类囊体膜蛋白在叶绿素生物合成中与 GUN5 协同发挥作用
DOI：
10.1016/j.xplc.2020.100094
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发表时间：
2020-09-14
影响因子：
10.5
通讯作者：
Luan S
中科院分区：
文献类型：
--
作者：
Zhang C;Zhang B;Mu B;Zheng X;Zhao F;Lan W;Fu A;Luan S
叶绿素（Chl）对于光合反应和叶绿体发育至关重要。虽然叶绿素生物合成的酶促途径已经建立，但叶绿素水平稳态的调控机制仍然很大程度上未知。在这项研究中，我们确定了CBD 1（叶绿素生物合成缺陷1），它在叶绿素生物合成的调节功能。CBD 1基因在绿色组织中特异表达，其蛋白产物包埋在类囊体膜上。此外，CBD 1与GUN 5（基因组解偶联5）精确共表达并在功能上相关。叶绿素代谢中间产物的分析表明，cbd 1和cbd 1gun 5突变体过量积累镁原卟啉IX（Mg-Proto IX）。此外，cbd 1突变体类囊体含有比野生型更少的镁，不仅由于较低的叶绿素含量，但也牵连CBD 1在镁运输。这得到了以下发现的支持：在低Mg条件下，CBD 1补充了Mg 2+摄取缺陷的沙门氏菌菌株。综上所述，这些结果表明，CBD 1功能协同与CHLH/GUN 5在Mg-Proto IX加工，并可能作为镁转运蛋白，以维持镁稳态的叶绿体。镁不仅是叶绿素的结构元素，而且是叶绿体中许多酶的辅因子。本研究表明，类囊体膜蛋白，CBD 1，功能协同与CHLH/GUN 5在叶绿素的生物合成，并作为镁转运蛋白，以维持镁稳态的叶绿体。
Chlorophyll (Chl) is essential for photosynthetic reactions and chloroplast development. While the enzymatic pathway for Chl biosynthesis is well established, the regulatory mechanism underlying the homeostasis of Chl levels remains largely unknown. In this study, we identified CBD1 (Chlorophyll Biosynthetic Defect1), which functions in the regulation of chlorophyll biosynthesis. The CBD1 gene was expressed specifically in green tissues and its protein product was embedded in the thylakoid membrane. Furthermore, CBD1 was precisely co-expressed and functionally correlated with GUN5 (Genome Uncoupled 5). Analysis of chlorophyll metabolic intermediates indicated that cbd1 and cbd1gun5 mutants over-accumulated magnesium protoporphyrin IX (Mg-Proto IX). In addition, the cbd1 mutant thylakoid contained less Mg than the wild type not only as a result of lower Chl content, but also implicating CBD1 in Mg transport. This was supported by the finding that CBD1 complemented a Mg2+ uptake-deficient Salmonella strain under low Mg conditions. Taken together, these results indicate that CBD1 functions synergistically with CHLH/GUN5 in Mg-Proto IX processing, and may serve as a Mg-transport protein to maintain Mg homeostasis in the chloroplast. Magnesium (Mg) is not only a structural element of chlorophyll but also a cofactor for a number of enzymes in the chloroplast. This study shows that a thylakoid membrane protein, CBD1, functions synergistically with CHLH/GUN5 in chlorophyll biosynthesis, and serves as a Mg-transport protein to maintain Mg homeostasis in the chloroplast.
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DOI：
10.1074/jbc.m109.025205
发表时间：
2009-09-11
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Adhikari ND;Orler R;Chory J;Froehlich JE;Larkin RM
通讯作者：
Larkin RM
影响因子：
5.1
作者：
Alawady, A;Reski, R;Grimm, B
通讯作者：
Grimm, B
影响因子：
3.1
作者：
Chekounova, E;Voronetskaya, V;Beck, CF
通讯作者：
Beck, CF
影响因子：
18
作者：
Chen, Xuemin;Pu, Hua;Liu, Lin
通讯作者：
Liu, Lin
影响因子：
4.1
作者：
Jensen, PE;Gibson, LCD;Hunter, CN
通讯作者：
Hunter, CN