Date: 8 May 2026 (Friday)
Time: 10:00 am – 11:00 am
Venue: Mrs Chen Yang Foo Oi Telemedicine Centre, 2/F, William M.W. Mong Block, 21 Sassoon Road 
Host: Professor Tao Ni

Dr. Zhenfeng Liu is currently a principal investigator at the State Key Laboratory of Biomacromolecules in the Institute of Biophysics (IBP), Chinese Academy of Sciences (CAS). He is also a professor as the College of Life Sciences in the University of Chinese Academy of Sciences. In 1998, he graduated from the Department of Biology in Xiamen University and received a Bachelor’s degree in Biology. During 1998-2004, he did doctoral research on plant light-harvesting complexes at the Institute Biophysics, CAS and received a Doctor-of-Science (Dr. Sc.) degree in Biophysics. Afterwards, he carried out postdoctoral research on bacterial mechanosensitive channels at the Department of Chemistry and Chemical Engineering in California Institute of Technology (Caltech) and appointed as a research associate at the Howard Hughes Medical Institute during the period between 2004 and 2010. He joined IBP, CAS in 2011 as a principal investigator and has been working there on the structures and functions of membrane proteins since then. His group mainly study the molecular mechanisms underlying the process of photosynthesis regulation, by combining multiple biochemical and biophysical approaches. His research works focus on the supramolecular basis of photosynthetic light-harvesting process in plants and algae (Nature, 2004；Nature, 2005；Plant Cell, 2015；Nature, 2016；Science, 2017；Nat. Plants, 2019；Nat. Plants, 2021；eLife, 2023；Sci. Adv., 2024), molecular mechanism of photosystem II repair (Nat. Commun., 2024; Nat. Plants, 2025), biogenesis and translocation of chloroplast proteins (Nature, 2023), etc.

Photosystem II (PSII), a supramolecular complex utilizing light energy to catalyse water oxidation and plastoquinone reduction, is pivotal for oxygenic photosynthesis in cyanobacteria, algae, and plants. It is highly susceptible to damages caused by excess photon energy. To restore the function of damaged PSII, a fundamental process mediated by numerous auxiliary factors repairs PSII on the thylakoid membrane through multiple steps. By applying biophysical and biochemical approaches, we have recently obtained and characterized a series of intermediate-state complexes involved in the PSII repair process. The structures of various PSII-repair complexes were solved at near-atomic resolutions by using the single-particle cryo-electron microscopy (cryo-EM) method. Firstly, an intermediate complex captured at the early stage contains three protein factors, namely Thylakoid Enriched Factor 14 (TEF14) and PSII repair factors 1 and 2 (PRF1 and PRF2), and a redox factor named a-tocopherol quinone (a-TQ). TEF14 and PRF1 binds to a core antenna complex CP47 at different regions, blocking PsbO and CP29 from associating with CP47 during the repair process. PRF2 and a-TQ flanks on two sides of a photoprotective subunit cyt b559, causing blockage of the QB site and preventing generation of reactive oxygen species. At the mid-to-late stage of PSII repair, the Thylakoid Enriched Fraction 30 (TEF30) is associated with a PSII core monomer (TEF30-C), two PSII core dimers (TEF30-C2-I and TEF30-C2-II) and a C2S-type PSII-LHCII supercomplex (TEF30-C2S). TEF30 clamps on the stromal surfaces of two modules (CP43 and RC47) to mediate their assembly and prevents peripheral antennae from associating with PSII-C prematurely. The transition from TEF30-C2-I to TEF30-C2-II, TEF30-C2S and mature C2S2 may involve a gradual sliding movement of PSII cores along the dimerization interface, to generate a zigzagged surface for three peripheral antennae (LHCII, CP29 and CP26). The results provide detailed mechanistic insights into the early disassembly and mid-to-late reassembly stages of PSII repair in green algae.

All are welcome.