Research Institute of Molecular Pathology (IMP), Vienna, Austria.
Nat Struct Mol Biol. 2011 Jun;18(6):728-31. doi: 10.1038/nsmb.2055. Epub 2011 May 1.
Deg1 is a chloroplastic protease involved in maintaining the photosynthetic machinery. Structural and biochemical analyses reveal that the inactive Deg1 monomer is transformed into the proteolytically active hexamer at acidic pH. The change in pH is sensed by His244, which upon protonation, repositions a specific helix to trigger oligomerization. This system ensures selective activation of Deg1 during daylight, when acidification of the thylakoid lumen occurs and photosynthetic proteins are damaged.
Deg1 是一种参与维持光合作用机器的叶绿体蛋白酶。结构和生化分析表明，无活性的 Deg1 单体在酸性 pH 下转化为具有蛋白水解活性的六聚体。pH 的变化由 His244 感知，当质子化时，His244 重新定位特定的螺旋以触发寡聚化。该系统确保 Deg1 在白天选择性激活，此时类囊体腔酸化并且光合蛋白受损。
