SAXS OF METHYLAMINE DEHYDROGENASE ELECTRON TRANSFER PROTEIN COMPLEXES

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。甲胺脱氢酶（MADH）是一种古老的细菌代谢酶，在前有氧环境中进化而来。它的厌氧起源是由它催化的高度进化的多步化学反应证明的，它使用辅助氧化还原蛋白伙伴，而不是分子氧，在催化过程中去除电子。通过这些类型的电子转移反应产生的能量是生物体内所有能量产生的基础。虽然是趋同进化的产物，但酶催化的还原化学与含铜胺氧化酶家族类似，其人类对应物与晚期糖尿病并发症和充血性心脏病的血管变化有关。利用单晶可见光谱、x射线晶体学和冷冻捕获以及小角度x射线散射的新组合，该项目将通过捕获反硝化副球菌MADH （PD-MADH）晶体中的催化中间体，并确定其结构，探索蛋白质如何在原子分辨率上控制其复杂的多步骤反应。通过研究这种高度发达的代谢系统，我们可以揭示地球上复杂生命进化过程中利用能量和物质的基本过程。线粒体和叶绿体中仍然存在古代厌氧氧化还原化学的一部分。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Methylamine dehydrogenase (MADH) is an ancient bacterial metabolic enzyme that evolved in a pre-aerobic world. Its anaerobic origins are attested to by the highly evolved multistep chemistry it catalyzes, and its use of ancillary redox protein partners, rather than molecular oxygen, to remove electrons during catalysis. The energy generated through these types of electron transfer reactions underlies all energy generation in living organisms. Although a product of convergent evolution, the reductive chemistry catalyzed by the enzyme is analogous to that of the copper-containing amine oxidase family, whose human counterparts are linked to late-diabetic complications and vascular changes in congestive heart disease. Using a novel combination of single crystal visible spectroscopy, X-ray crystallography and freeze-trapping, and small-angle X-ray scattering, this project will probe how the protein controls its complex multistep reaction at atomic resolution by trapping catalytic intermediates in Paracoccus denitrificans MADH (PD-MADH) containing crystals, and determining their structures. By studying this highly developed metabolic system, a part of the ancient anaerobic redox chemistries still found in mitochondria and chloroplasts today, we can shed light on the fundamental processes of harnessing energy and materials that evolved complex life on earth.