时间：2023年8月28日（周一）上午10:30~12:00

Time：10:30-12:00 AM, Monday, August 28, 2023

地点：西湖大学云谷校区 E9-109教室

Venue: E9-109, Yungu Campus

主持人：西湖大学生命科学学院 助理教授李小波

Host: Assistant Professor Xiaobo Li, School of life Sciences

主讲人/Speaker：

Arthur Grossman

Senior Staff Scientist at The Carnegie Institution for Science, 

Department of Plant Biology, Professor of Department of Biology at Stanford University

报告题目/Title:

Pyrenoid Associated Methyltransferase Homolog Involved in Photosystem I Biogenesis

讲座摘要/Abstract:

Oxygen (O2), a dominant element in the atmosphere and an essential molecule for most life on Earth, is produced by the photosynthetic oxidation of water. However, metabolic activity can cause the generation of reactive O2 species (ROS) that can damage lipids, proteins, nucleic acids, and threaten cell viability. To identify and characterize mechanisms that allow cells to cope with the potentially negative effects of O2 reactivity, we performed a high-throughput O2 sensitivity screen on a genome-wide insertional mutant library of the unicellular alga Chlamydomonas reinhardtii. This screen led to identification of several genes that, when disrupted, alter the cell’s sensitivity to O2 in the light. One of these genes encodes a protein designated Rubisco methyltransferase 2 (RMT2). Although this protein has homology to methyltransferases, it has not yet been demonstrated to catalyze methyltransferase reactions. Furthermore, the rmt2 mutant has not been observed to be compromised for Rubisco (first enzyme of Calvin-Benson Cycle; CBC) function, although the mutant cells were light sensitive, which reflects a marked decrease in the level of photosystem I (PSI), with much less of an impact on the other photosynthetic complexes. While the RMT2 protein has no apparent chloroplast targeting sequence, rescue of the mutant with a wild-type (WT) copy of the gene fused to the mNeonGreen fluorophore indicates that the protein is within the chloroplast and enriched in/around the pyrenoid (an intrachloroplast structure found in many algae that contains the CO2-fixing enzyme Rubisco and is likely a hypoxic compartment), but we also observe it in the stroma. Finally, proximity labeling suggests that RMT2 interact with various proteins associated with PSI biogenesis. These results suggest that RMT2 may serve an important role in the biogenesis of PSI and that PSI biogenesis may be enriched around or within the pyrenoid, which may reflect the impact of O2/reactive O2 species on the efficiency with which PSI can assemble.

讲座联系人/Contact:

科技合作部Sci-tech02@westlake.edu.cn