Functional and structural principles of the MoxR/VWA chaperone system in target protein recognition and modification.

MoxR/VWA 伴侣系统在靶蛋白识别和修饰中的功能和结构原理。

• 批准号: 493617395
• 负责人: Dr. Maximilian Kahle
• 金额: --
• 依托单位: Arbeitsgruppe Biochemie
• 依托单位国家: 德国
• 项目类别: WBP Position
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/493617395?language=en
• 关键词: Functional; structural; principles; MoxR; VWA

Many fundamental processes in the cell such as replication and transcription of DNA, folding and unfolding of proteins or the assembly and disassembly of multi-protein complexes depend on the ability to convert chemical energy into mechanical work. AAA+ ATPases, also referred to as molecular motors, are involved in a great number of such functions and are wide spread within all three domains of life. AAA+ motors commonly remodel the conformation of their target macromolecules driven by ATP hydrolysis. MoxR proteins, a subfamily of AAA+ ATPases, are ubiquitous in bacteria and archaea. They are suggested to represent a group of molecular chaperons, primarily involved in protein maturation and cofactor insertion processes. Interestingly, many MoxR proteins are genetically linked with proteins containing the Von Willebrand Factor Type A (VWA) domain, indicating that they function together. However, the general mechanism of MoxR proteins is only poorly understood and the experimental data is limited. It was recently found that the MoxR protein NorQ from Paracoccus denitrificans facilitates non-heme iron cofactor insertion into nitric oxide reductase (cNOR), a multi-cofactor membrane protein involved in the bacterial denitrification chain. Although the specific metal insertion mechanism remained largely speculative, it was found that the VWA protein NorD is essential for the process and that NorQ and NorD form a complex. A number of studies support a cooperative action of MoxR/VWA proteins and point at a general function in the maturation and regulation of enzymes including rubisco, respiratory complex I, fumarate dehydrogenase, CO dehydrogenase and methanol dehydrogenase.The overall goal of this study is to characterize the shared structural and functional features of this chaperon system by expressing four different MoxR/VWA pairs including NorQD as our main model system. We will determine the high-resolution cryo-EM structures of the different chaperone complexes alone or in interaction with their respective targets. The structural data will be the basis for further mutagenesis analysis combined with a set of kinetic techniques to shed light on the general mechanism of these understudied chaperons.The results of this study are expected to give novel insights into how cofactor assembly can be performed efficiently on a diverse set of target enzymes in the cell. More specifically, we will expand our knowledge of the unknown mechanism of non-heme iron cofactor insertion. In order to design and produce novel biocatalysts for the chemical industry it will be necessary to deepen our understanding of the fundamental mechanisms of metallo-protein assembly. In addition, many MoxR/VWA protein pairs interact with bacterial respiratory enzymes, which makes this chaperon system a potential target for future antimicrobial drugs.

细胞中的许多基本过程，例如 DNA 的复制和转录、蛋白质的折叠和展开或多蛋白质复合物的组装和分解，都依赖于将化学能转化为机械能的能力。 AAA+ ATP 酶，也称为分子马达，参与​​大量此类功能，并广泛分布于生命的所有三个领域。 AAA+ 马达通常会重塑由 ATP 水解驱动的目标大分子的构象。 MoxR 蛋白是 AAA+ ATP 酶的一个亚家族，普遍存在于细菌和古细菌中。它们被认为代表一组分子伴侣，主要参与蛋白质成熟和辅因子插入过程。有趣的是，许多 MoxR 蛋白与含有 A 型血管性血友病因子 (VWA) 结构域的蛋白在基因上相关，表明它们一起发挥作用。然而，人们对MoxR蛋白的一般机制知之甚少，实验数据也有限。最近发现，脱氮副球菌的 MoxR 蛋白 NorQ 有助于非血红素铁辅助因子插入一氧化氮还原酶 (cNOR)，一氧化氮还原酶是一种参与细菌反硝化链的多辅助因子膜蛋白。尽管具体的金属插入机制在很大程度上仍处于推测状态，但人们发现 VWA 蛋白 NorD 对于该过程至关重要，并且 NorQ 和 NorD 形成复合物。许多研究支持 MoxR/VWA 蛋白的协同作用，并指出在 rubisco、呼吸复合物 I、富马酸脱氢酶、CO 脱氢酶和甲醇脱氢酶等酶的成熟和调节中的一般功能。本研究的总体目标是通过表达四种不同的 MoxR/VWA 对来表征该伴侣系统的共同结构和功能特征，包括 NorQD 作为我们的主要模型系统。我们将单独确定不同伴侣复合物或与其各自目标相互作用的高分辨率冷冻电镜结构。结构数据将成为进一步诱变分析的基础，结合一系列动力学技术，以阐明这些正在研究的伴侣的一般机制。这项研究的结果预计将为如何在细胞中的多种目标酶上有效地进行辅因子组装提供新的见解。更具体地说，我们将扩展对非血红素铁辅因子插入的未知机制的了解。为了设计和生产用于化学工业的新型生物催化剂，有必要加深我们对金属-蛋白质组装基本机制的理解。此外，许多 MoxR/VWA 蛋白对与细菌呼吸酶相互作用，这使得该伴侣系统成为未来抗菌药物的潜在目标。