Helical allophycocyanin nanotubes absorb far-red light in a thermophilic cyanobacterium
- Yale Univ., New Haven, CT (United States); Yale University; Yale University
- Vrije Univ., Amsterdam (Netherlands)
- Pennsylvania State Univ., University Park, PA (United States)
- Yale Univ., New Haven, CT (United States)
- City College of New York, NY (United States)
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.
- Research Organization:
- Yale Univ., New Haven, CT (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
- Grant/Contract Number:
- FG02-05ER15646; SC0001423
- OSTI ID:
- 2339809
- Journal Information:
- Science Advances, Journal Name: Science Advances Journal Issue: 12 Vol. 9; ISSN 2375-2548
- Publisher:
- AAASCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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