National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
K99GM140174
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
T32GM008283
米国
引用
ジャーナル: Sci Adv / 年: 2023 タイトル: Helical allophycocyanin nanotubes absorb far-red light in a thermophilic cyanobacterium. 著者: Christopher J Gisriel / Eduard Elias / Gaozhong Shen / Nathan T Soulier / David A Flesher / M R Gunner / Gary W Brudvig / Roberta Croce / Donald A Bryant / 要旨: To compete in certain low-light environments, some cyanobacteria express a paralog of the light-harvesting phycobiliprotein, allophycocyanin (AP), that strongly absorbs far-red light (FRL). Using ...To compete in certain low-light environments, some cyanobacteria express a paralog of the light-harvesting phycobiliprotein, allophycocyanin (AP), that strongly absorbs far-red light (FRL). Using cryo-electron microscopy and time-resolved absorption spectroscopy, we reveal the structure-function relationship of this FRL-absorbing AP complex (FRL-AP) that is expressed during acclimation to low light and that likely associates with chlorophyll a-containing photosystem I. FRL-AP assembles as helical nanotubes rather than typical toroids due to alterations of the domain geometry within each subunit. Spectroscopic characterization suggests that FRL-AP nanotubes are somewhat inefficient antenna; however, the enhanced ability to harvest FRL when visible light is severely attenuated represents a beneficial trade-off. The results expand the known diversity of light-harvesting proteins in nature and exemplify how biological plasticity is achieved by balancing resource accessibility with efficiency.