Zhou Yunpeng, Cierpicki Tomasz, Jimenez Ricardo H Flores, Lukasik Stephen M, Ellena Jeffrey F, Cafiso David S, Kadokura Hiroshi, Beckwith Jon, Bushweller John H
Department of Molecular Physiology and Biological Physics, University of Virginia Health Sciences, Charlottesville, VA 22908, USA.
Mol Cell. 2008 Sep 26;31(6):896-908. doi: 10.1016/j.molcel.2008.08.028.
We describe the NMR structure of DsbB, a polytopic helical membrane protein. DsbB, a bacterial cytoplasmic membrane protein, plays a key role in disulfide bond formation. It reoxidizes DsbA, the periplasmic protein disulfide oxidant, using the oxidizing power of membrane-embedded quinones. We determined the structure of an interloop disulfide bond form of DsbB, an intermediate in catalysis. Analysis of the structure and interactions with substrates DsbA and quinone reveals functionally relevant changes induced by these substrates. Analysis of the structure, dynamics measurements, and NMR chemical shifts around the interloop disulfide bond suggest how electron movement from DsbA to quinone through DsbB is regulated and facilitated. Our results demonstrate the extraordinary utility of NMR for functional characterization of polytopic integral membrane proteins and provide insights into the mechanism of DsbB catalysis.
我们描述了多跨膜螺旋蛋白DsbB的核磁共振结构。DsbB是一种细菌细胞质膜蛋白，在二硫键形成过程中起关键作用。它利用膜嵌入醌的氧化能力，使周质蛋白二硫键氧化剂DsbA重新氧化。我们确定了DsbB的环间二硫键形式的结构，这是催化过程中的一个中间体。对该结构以及与底物DsbA和醌相互作用的分析揭示了这些底物诱导的功能相关变化。对环间二硫键周围的结构、动力学测量和核磁共振化学位移的分析表明了电子如何通过DsbB从DsbA转移到醌并受到调节和促进。我们的结果证明了核磁共振在多跨膜整合膜蛋白功能表征方面的非凡效用，并为DsbB催化机制提供了见解。
