Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt am Main D-60438, Germany.
Department of Chemistry, University of Crete, Voutes Heraklion GR-70013, Greece.
Proc Natl Acad Sci U S A. 2023 Jan 31;120(5):e2216734120. doi: 10.1073/pnas.2216734120. Epub 2023 Jan 24.
Light energy absorption and transfer are very important processes in photosynthesis. In green sulfur bacteria light is absorbed primarily by the chlorosomes and its energy is transferred via the Fenna-Matthews-Olson (FMO) proteins to a homodimeric reaction center (RC). Here, we report the cryogenic electron microscopic structure of the intact FMO-RC apparatus from at 2.5 Å resolution. The FMO-RC apparatus presents an asymmetric architecture and contains two FMO trimers that show different interaction patterns with the RC core. Furthermore, the two permanently bound transmembrane subunits PscC, which donate electrons to the special pair, interact only with the two large PscA subunits. This structure fills an important gap in our understanding of the transfer of energy from antenna to the electron transport chain of this RC and the transfer of electrons from reduced sulfur compounds to the special pair.
光能的吸收和传递在光合作用中非常重要。在绿硫细菌中，光主要被类囊体吸收，其能量通过 Fenna-Matthews-Olson（FMO）蛋白传递到同源二聚体反应中心（RC）。在这里，我们报道了来自的完整 FMO-RC 装置在 2.5Å分辨率下的低温电子显微镜结构。FMO-RC 装置呈现出非对称的结构，包含两个 FMO 三聚体，它们与 RC 核心表现出不同的相互作用模式。此外，两个永久结合的跨膜亚基 PscC 将电子供体传递给特殊对，仅与两个大的 PscA 亚基相互作用。该结构填补了我们对该 RC 天线到电子传递链能量传递以及还原态硫化合物到特殊对电子传递的理解中的一个重要空白。
