A distinct LHCI arrangement is recruited to photosystem I in Fe- starved green algae

• 成果类型: Article
• 署名作者: Liu, Helen W.; Khera, Radhika; Grob, Patricia; Gallaher, Sean D.; Purvine, Samuel O.; Nicora, Carrie D.; Lipton, Mary S.; Niyogi, Krishna K.; Nogales, Eva; Iwai, Masakazu; Merchant, Sabeeha S.
• 署名单位: University of California System; University of California Berkeley; University of California System; University of California Berkeley; Howard Hughes Medical Institute; University of California System; University of California Berkeley; University of California System; University of California Berkeley; United States Department of Energy (DOE); Pacific Northwest National Laboratory; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-10105
• DOI: 10.1073/pnas.2500621122
• 发表日期: 2025-06-24
• 关键词: light-harvesting complex; chlorophyll-protein complex; iron-deficiency; chloroplast ferredoxin; plasma-membrane; dunaliella; flavodoxin; stress; binding; photosynthesis

摘要

Iron (Fe) availability limits photosynthesis at a global scale where Fe-rich photosystem (PS) I abundance is drastically reduced in Fe-poor environments. We used single-particle cryoelectron microscopy to reveal a unique Fe starvation-dependent arrangement of light-harvesting chlorophyll (LHC) proteins where Fe starvation-induced TIDI1 is found in an additional tetramer of LHC proteins associated with PSI in Dunaliella tertiolecta and Dunaliella salina. These cosmopolitan green algae are resilient to poor Fe nutrition. TIDI1 is a distinct LHC protein that co-occurs in diverse algae with flavodoxin (an Fe-independent replacement for the Fe-containing ferredoxin). The antenna expansion in eukaryotic algae we describe here is reminiscent of the iron-starvation induced (isiA-encoding) antenna ring in cyanobacteria, which typically co-occurs with isiB, encoding flavodoxin. Our work showcases the convergent strategies that evolved after the Great Oxidation Event to maintain PSI capacity.