Structural highlights
Function
A0A2G8PAX6_9SYNE
Publication Abstract from PubMed
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.
Helical allophycocyanin nanotubes absorb far-red light in a thermophilic cyanobacterium.,Gisriel CJ, Elias E, Shen G, Soulier NT, Flesher DA, Gunner MR, Brudvig GW, Croce R, Bryant DA Sci Adv. 2023 Mar 24;9(12):eadg0251. doi: 10.1126/sciadv.adg0251. Epub 2023 Mar , 24. PMID:36961897[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Gisriel CJ, Elias E, Shen G, Soulier NT, Flesher DA, Gunner MR, Brudvig GW, Croce R, Bryant DA. Helical allophycocyanin nanotubes absorb far-red light in a thermophilic cyanobacterium. Sci Adv. 2023 Mar 24;9(12):eadg0251. PMID:36961897 doi:10.1126/sciadv.adg0251
