该课题组研究人员报道了来自热绒球藻PCC 7203的远红色PSI的两个低温电镜结构，允许8个叶绿素f分子的分配，包括氧化还原活性的A-1B。电荷分离引起的吸收差谱模拟表明，只有考虑A-1B位点叶绿素f的存在才能再现实验光谱。叶绿素f的位置，波长分配和保守的远红特异性残基为长波光子的有效主题提供了功能见解。
据悉，含叶绿素f光系统的发现及其长波长光化学反应，代表了一种独特的、低能量的含氧光合作用模式。对含叶绿素f光系统I的结构研究可以识别出部分叶绿素f位点，但在光化学活性色素中没有发现，因此叶绿素f不发挥光化学作用。
附：英文原文
Title: Locating the missing chlorophylls f in far-red photosystem I
Author: Giovanni Consoli, Fiazall Tufail, Ho Fong Leong, Stefania Viola, Geoffry A. Davis, Nicholas Rew, Daniel Medranda, Michael Hofer, Paul Simpson, Marco Sandrin, Benoit Chachuat, Jenny Nelson, Thomas Renger, James W. Murray, Andrea Fantuzzi, A. William Rutherford
Issue&Volume: 2025-10-09
Abstract: The discovery of chlorophyll f-containing photosystems, with their long-wavelength photochemistry, represented a distinct, low-energy paradigm for oxygenic photosynthesis. Structural studies on chlorophyll f-containing photosystem I could identify some chlorophylls f sites, but none among the photochemically active pigments and concluded that chlorophyll f plays no photochemical role. Here, we report two cryo-EM structures of far-red PSI from Chroococcidiopsis thermalis PCC 7203, allowing the assignment of eight chlorophylls f molecules, including the redox active A-1B. Simulations of absorption difference spectra induced by charge separation indicate that the experimental spectra can be reproduced only by considering the presence of a chlorophyll f at the A-1B site. The chlorophyll f locations, wavelength assignments, and conserved far-red-specific residues provide functional insights for efficient use of long wavelength photons.
DOI: ado6830
Source: https://www.science.org/doi/10.1126/science.ado6830