Concentration-based self-assembly of phycocyanin
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Cyanobacteria light-harvesting complexes can change their structure to cope with fluctuating environmental conditions. Studying in vivo structural changes is difficult owing to complexities imposed by the cellular environment. Mimicking this system in vitro is challenging, as well. The in vivo system is highly concentrated, and handling similar in vitro concentrated samples optically is difficult because of high absorption. In this research, we mapped the cyanobacteria antennas self-assembly pathways using highly concentrated solutions of phycocyanin (PC) that mimic the in vivo condition. PC was isolated from the thermophilic cyanobacterium Thermosynechococcus vulcanus and measured by several methods. PC has three oligomeric states: hexamer, trimer, and monomer. We showed that the oligomeric state was changed upon increase of PC solution concentration. This oligomerization mechanism may enable photosynthetic organisms to adapt their light-harvesting system to a wide range of environmental conditions.
KeywordsPhycocyanin Oligomerization TEM SAXS Native mass spectrometry
Transmission electron microscopy
Cryogenic transmission electron microscopy
Small-angle X-ray scattering
This research was supported by a Grant No. 3-12405(151235) from the Ministry of Science, Technology and Space, Israel, the National Science Council (NSC) of Taiwan, the Israel Science Foundation (843/16) and the US-Israel Bi-National Science Fund (2014395).
- Guinier A, Fournet G (1955) Small angle scattering of X-rays. Wiley, HobokenGoogle Scholar
- Hall DO, Rao K (1999) Photosynthesis. Cambridge University Press, CambridgeGoogle Scholar
- Horton P, Johnson MP, Perez-Bueno ML et al (2008) Photosynthetic acclimation: does the dynamic structure and macro-organisation of photosystem II in higher plant grana membranes regulate light harvesting states? FEBS J 275:1069–1079. doi: 10.1111/j.1742-4658.2008.06263.x CrossRefPubMedGoogle Scholar
- Schirmer T, Bode W, Huber R et al (1985) X-ray crystallographic structure of the light-harvesting biliprotein C-phycocyanin from the thermophilic cyanobacterium Mastigocladus laminosus and its resemblance to globin structures. J Mol Biol 184:257–277. doi: 10.1016/0022-2836(85)90379-1 CrossRefPubMedGoogle Scholar