Department of Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, Technische Universität Braunschweig, Germany.
Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
FEBS Lett. 2019 Nov;593(22):3190-3197. doi: 10.1002/1873-3468.13586. Epub 2019 Sep 8.
In higher plants, PsbS is known to play a key role in the regulation of photosynthetic light harvesting. However, the molecular mechanism and role of electronic carotenoid-chlorophyll (Chl) interactions for the downregulation of excess excitation (nonphotochemical energy quenching, NPQ) are still poorly understood. Here, we explored carotenoid → Chl energy transfer in isolated grana thylakoid membranes from mutants either deficient in or overexpressing PsbS. Since it was suggested that PsbS regulates the supramolecular protein network to control NPQ, we varied this network by diluting the grana protein densities. Our results indicate that different electronic quenching mechanisms are operative in grana thylakoids: a PsbS-dependent mechanism and a membrane protein density-dependent mechanism that is also operative in the absence of PsbS.
在高等植物中，已知 PsbS 在调节光合作用光捕获中起着关键作用。然而，电子类胡萝卜素-叶绿素（Chl）相互作用对于下调过剩激发（非光化学能量猝灭，NPQ）的分子机制和作用仍知之甚少。在这里，我们在缺乏或过表达 PsbS 的突变体的分离类囊体膜中探索了类胡萝卜素→Chl 能量转移。由于有人提出 PsbS 通过调节超分子蛋白质网络来控制 NPQ，因此我们通过稀释类囊体蛋白密度来改变该网络。我们的结果表明，在类囊体中存在不同的电子猝灭机制：一种依赖 PsbS 的机制和一种膜蛋白密度依赖的机制，即使在缺乏 PsbS 的情况下也能发挥作用。
