Structural Basis of Metallocofactor Delivery and Repair

项目总结/摘要 复杂的和反应性的金属辅因子通常负责对细胞生长至关重要的具有挑战性的化学反应。 新陈代谢.因此，这些辅因子向其靶酶的转运通常 涉及多种蛋白质和复杂的传递途径。任何这些成分的突变都可能导致 途径的破坏导致靶酶的总体活性不足并导致疾病 状态，如维生素B12（钴胺素，Cbl）递送途径的情况。在本建议中，我们将研究 来自人类、扭脱甲基杆菌和耐金属贪铜菌的酶，以确定 Cbl运输和安装的分子机制。我们的方法包括使用各种生物物理学 这些方法将使我们能够可视化G蛋白伴侣及其靶点Cbl之间的相互作用， 在Cbl递送途径的最后一步中依赖性地表达。这项工作将在结构基础上提供信息， 分子伴侣介导的Cbl的递送和修复。通过结合X射线晶体学，电子显微镜和 电子顺磁共振光谱，我们将探讨G- 参与腺苷钴胺素在其靶突变酶中的安装和修复的蛋白伴侣。

PROJECT SUMMARY/ABSTRACT Complex and reactive metallocofactors are often responsible for challenging chemistry that is critical to cellular metabolism. It is therefore not surprising that the transport of these cofactors to their target enzymes often involves multiple proteins and complex delivery pathways. Mutations in any of these components may result in a breakdown of the pathway causing deficits in the overall activity of the target enzyme and leading to a disease state, as in the case with the vitamin B12 (cobalamin, Cbl) delivery pathway. In this proposal, we will study enzymes from humans, Methylobacterium extorquens and Cupriavidus metallidurans in order to determine the molecular mechanisms of Cbl transport and installation. Our approach involves the use of a variety of biophysical methods that will allow us to visualize the interactions between a G-protein chaperone and its target Cbl- dependent mutase in the final step of the Cbl delivery pathway. This work will inform on the structural basis of chaperone-mediated delivery and repair of Cbl. By combining X-ray crystallography, electron microscopy and electron paramagnetic resonance spectroscopy, we will explore the molecular mechanism of action of the G- protein chaperones involved in the installation and repair of adenosylcobalamin in their target mutases.