AppA, a Redox Regulator of Photosystem Formation in Rhodobacter sphaeroides 2.4.1, Is a Flavoprotein
AppA, a Redox Regulator of Photosystem Formation in Rhodobacter sphaeroides 2.4.1, Is a Flavoprotein
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AppA 是球形红细菌 2.4.1 中光系统形成的氧化还原调节剂，是一种黄素蛋白
DOI：
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发表时间：
1998
影响因子：
4.8
通讯作者：
S. Kaplan
中科院分区：
文献类型：
--
作者：
M. Gomelsky;S. Kaplan
当兼性光异养细菌球形红假单胞菌2.4.1从好氧条件转换到厌氧光合作用条件时，AppA蛋白是增加光系统基因表达所必需的。APPA与已有功能的蛋白质没有明显的相似性。遗传证据表明，它的作用是通过调节抑制物PpsR的活性来发挥作用的，该抑制物控制着多个光系统基因的表达。为了深入了解AppA参与依赖氧化还原的光系统基因表达的本质，在大肠杆菌中过表达了AppA基因。APPA以不溶性包涵体的形式出现。纯化的包涵体中含有FAD。通过过度表达各种缺失衍生物，我们能够定位足以与FAD结合的AppA区域，大约120个氨基末端残基。为了评估FAD结合在AppA功能中的作用，我们构建了一个缺少整个FAD结合结构域的AppA衍生物。令人惊讶的是，这种衍生品几乎与全长Appa蛋白一样，补充了经历从有氧到无氧光合作用生长条件转变的Appa零突变体。当检查APPA的氨基末端部分的序列时，发现它不包含任何已知的黄素结合基序。然而，我们发现了两个功能未知的开放阅读框，它们与AppA的氨基末端有很大的相似性，即聚球藻。Srl1694和E.ColiF403。后一个基因被扩增并过表达。结果表明，部分纯化的F403蛋白含有辅因子FAD。因此，我们得出结论，AppA的氨基末端代表了存在于一小群细菌蛋白中的一个新的FAD结合域。APPA与FAD的结合可能是该调节蛋白如何参与氧化还原调节反应的第一个线索。
The AppA protein is required for increased photosystem gene expression upon transition of the facultatively photoheterotrophic bacterium Rhodobacter sphaeroides 2.4.1 from aerobic to anaerobic photosynthetic conditions. AppA shows no obvious similarity to proteins with established function. Genetic evidence suggests that its effect is exerted through modulation of the activity of the repressor PpsR, which controls expression of multiple photosystem genes. To gain insight into the nature of AppA involvement in redox-dependent photosystem gene expression, theappA gene was overexpressed in Escherichia coli. AppA was produced as insoluble inclusion bodies. The purified inclusion bodies were found to contain FAD. By overexpressing various deletion derivatives, we were able to localize the region of AppA sufficient for FAD binding to approximately 120 amino-terminal residues. To assess the role of FAD binding in AppA function, we constructed an AppA derivative lacking the entire FAD binding domain. Surprisingly, this derivative complemented the AppA null mutant undergoing transition from aerobic to anaerobic photosynthetic growth conditions almost to the same extent as the full-length AppA protein. When the sequence of the amino-terminal portion of AppA was examined, it was shown not to contain any known flavin binding motifs. However, two open reading frames of unknown function, showing significant similarity to the amino terminus of AppA, were identified,i.e. Synechocystis sp. Srl1694 and E. coli F403. The latter gene was amplified and overexpressed inE. coli, and the partially purified F403 protein was found to contain FAD as a cofactor. We have therefore concluded that the amino terminus of AppA represents a novel FAD binding domain present in a small group of bacterial proteins. The binding of FAD by AppA may be the first clue as to how this regulatory protein is involved in redox-regulated reactions.
CDP-6-脱氧-δ 3,4-葡萄糖烯还原酶的机理研究：通过化学修饰和定点诱变探讨半胱氨酸残基在催化中的作用。
影响因子：
2.9
作者：
Ploux,O;Lei,Y;Vatanen,K;Liu,HW
通讯作者：
Liu,HW