Roseiflexus castenholzii is a new type thermophilic filamentous anoxygenic photosynthetic bacterium, it acquired a unique and high efficient light harvesting and electron transport system during evolution. Different from higher plants and other photosynthetic bacteria, it doesn’t contain the antenna complexes, the only light harvesting complex (LH) form a ring like structure, having the L, M and cytochrome c subunits composed reaction center (RC) tightly bound in middle. Especially, a novel electron carrier protein complex ACIII replaced the cytochrome bc₁/b₆f complex in the canonical electron transport chain of photosynthesis and respiration. It transfers electron from the reaction center to a new blue copper protein auracyanin, drives formation of the transmembrane proton gradient, providing energy for bacterial growth. However, this novel photosynthetic system has only been globally investigated in a preliminary way.

Our group aims to determine the three dimensional structures of the core photosynthetic and electron transport complexes of Roseiflexus castenholzii at atomic resolution, combining X-ray crystallography and cryoEM technique, and illustrate the molecular mechanisms of light harvesting, electron transfer and energy transformation by functional studies (Nat Commun. 2018；Sci Adv, 2020；Photosynth Res. 2020) This work will contribute to resource recycling, development of controllable biological reaction devices and exploration of new resources of energy. Currently, this direction obtained financial support from NSFC (32171227, 2022-2025 and 31570738, 2016-2019).