Construction of a highly stable artificial glutathione peroxidase on a protein nanoring

Stable Protein One (SP1) is a boiling-stable oligomeric protein. The unique characteristics of SP1 offer a scaffold to design artificial enzymes against extreme temperature. Here, an efficient antioxidase is successfully constructed on the ring-shaped SP1 homododecamer. By means of computational design and genetic engineering, the active center of glutathione peroxidase (GPx), selenocysteine (Sec), is introduced to the SP1 monomer surface, and the self-assembly properties of the protein monomer lead to a ring-shaped SP1 with homododecamer catalytic selenium centers. This artificial selenoenzyme exhibits high GPx catalytic activity and shows a typical ping-pong kinetic mechanism. Moreover, it has a significantly broader temperature range and high thermostability. Owing to having multi-GPx active centers on a SP1 oligomer, this selenium-containing biomacromolecule exerts an excellent capability to protect cells from oxidative damage at the mitochondrial level. This strategy represents a new way to develop thermostable artificial nanoenzymes for some specific applications.

稳定蛋白一 (SP1) 是一种煮沸稳定的寡聚蛋白。 SP1 的独特特性为设计抗极端温度的人工酶提供了支架。在此，在环形 SP1 同十二聚体上成功构建了高效的抗氧化酶。通过计算设计和基因工程，将谷胱甘肽过氧化物酶（GPx）的活性中心硒代半胱氨酸（Sec）引入到SP1单体表面，利用蛋白质单体的自组装特性形成具有同十二聚体催化硒中心的环形SP1。这种人工硒酶表现出高 GPx 催化活性，并表现出典型的乒乓动力学机制。此外，它具有更宽的温度范围和高热稳定性。由于在SP1寡聚体上具有多个GPx活性中心，这种含硒生物大分子在线粒体水平上发挥了出色的保护细胞免受氧化损伤的能力。该策略代表了一种为某些特定应用开发热稳定性人造纳米酶的新方法。