Research Center for Industries of the Future, Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China.
Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China.
Science. 2023 Oct 6;382(6666):92-98. doi: 10.1126/science.adg7921. Epub 2023 Oct 5.
Marine and terrestrial photosynthesis exhibit a schism in the accessory chlorophyll (Chl) that complements the function of Chl : Chl for green plants versus Chl for most eukaryotic phytoplankton. The enzymes that mediate Chl biosynthesis have long remained elusive. In this work, we identified the CHLC dioxygenase (Phatr3_J43737) from the marine diatom as the Chl synthase. The mutants lacked Chl , instead accumulating its precursors, and exhibited growth defects. In vitro, recombinant CHLC protein converted these precursors into Chl , thereby confirming its identity. Phylogenetic evidence demonstrates conserved use of CHLC across phyla but also the existence of distinct Chl synthases in different algal groups. Our study addresses a long-outstanding question with implications for both contemporary and ancient marine photosynthesis.
海洋和陆地光合作用在辅助叶绿素（Chl）方面表现出分裂，补充了 Chl 的功能：Chl 用于绿色植物，而 Chl 用于大多数真核浮游植物。介导 Chl 生物合成的酶长期以来一直难以捉摸。在这项工作中，我们从海洋硅藻中鉴定出 CHLC 加双氧酶（Phatr3_J43737）为 Chl 合酶。 突变体缺乏 Chl ，而是积累其前体，并表现出生长缺陷。在体外，重组 CHLC 蛋白将这些前体转化为 Chl ，从而确认了其身份。系统发育证据表明 CHLC 在门之间的保守使用，但也存在不同藻类群体中不同的 Chl 合酶。我们的研究解决了一个长期存在的问题，对当代和古代海洋光合作用都有影响。
