A chlorophyll c synthase widely co-opted by phytoplankton

• 成果类型: Article
• 署名作者: Jiang, Yanyou; Cao, Tianjun; Yang, Yuqing; Zhang, Huan; Zhang, Jingyu; Li, Xiaobo
• 署名单位: Westlake University; Westlake University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13286
• DOI: 10.1126/science.adg7921
• 发表日期: 2023-10-06
• 页码: 92-98
• 关键词: diatom phaeodactylum-tricornutum; plastid evolution; protein; hypothesis; endosymbioses; biosynthesis; cryptophytes; haptophytes; absorption; mechanism

摘要

Marine and terrestrial photosynthesis exhibit a schism in the accessory chlorophyll (Chl) that complements the function of Chl a: Chl b for green plants versus Chl c for most eukaryotic phytoplankton. The enzymes that mediate Chl c biosynthesis have long remained elusive. In this work, we identified the CHLC dioxygenase (Phatr3_J43737) from the marine diatom Phaeodactylum tricornutum as the Chl c synthase. The chlc mutants lacked Chl c, instead accumulating its precursors, and exhibited growth defects. In vitro, recombinant CHLC protein converted these precursors into Chl c, thereby confirming its identity. Phylogenetic evidence demonstrates conserved use of CHLC across phyla but also the existence of distinct Chl c synthases in different algal groups. Our study addresses a long-outstanding question with implications for both contemporary and ancient marine photosynthesis.