Paulsen Candice E, Carroll Kate S
Chemical Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109-2216, USA.
Chem Biol. 2009 Feb 27;16(2):217-25. doi: 10.1016/j.chembiol.2009.01.003. Epub 2009 Feb 20.
Saccharomyces cerevisiae responds to elevated levels of hydrogen peroxide in its environment via a redox relay system comprising the thiol peroxidase Gpx3 and transcription factor Yap1. In this signaling pathway, a central unresolved question is whether cysteine sulfenic acid modification of Gpx3 is required for Yap1 activation in cells. Here we report that cell-permeable chemical probes, which are selective for sulfenic acid, inhibit peroxide-dependent nuclear accumulation of Yap1, trap the Gpx3 sulfenic acid intermediate, and block formation of the Yap1-Gpx3 intermolecular disulfide directly in cells. In addition, we present electrostatic calculations that show cysteine oxidation is accompanied by significant changes in charge distribution, which might facilitate essential conformational rearrangements in Gpx3 during catalysis and intermolecular disulfide formation with Yap1.
酿酒酵母通过一个由硫醇过氧化物酶Gpx3和转录因子Yap1组成的氧化还原中继系统，对其环境中过氧化氢水平的升高做出反应。在这个信号通路中，一个核心的未解决问题是，细胞中Yap1的激活是否需要Gpx3的半胱氨酸亚磺酸修饰。在这里我们报告，对亚磺酸具有选择性的细胞可渗透化学探针，抑制Yap1的过氧化物依赖性核积累，捕获Gpx3亚磺酸中间体，并直接在细胞中阻止Yap1-Gpx3分子间二硫键的形成。此外，我们提供的静电计算表明，半胱氨酸氧化伴随着电荷分布的显著变化，这可能有助于Gpx3在催化过程中以及与Yap1形成分子间二硫键时发生必要的构象重排。
