T=75 icosahedral carboxysome
The carboxysome enhances CO2 fixation inside many photosynthetic and chemoautotrophic bacterial cells by encapsulating the key enzymes ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) and carbonic anhydrase. Interestingly this structure is icosahedral like viral capsid and has a T=75 symmetry .
T=75 icosahedral carboxysome is composed of 12 pentameric and 740 hexameric capsomeres for a total of 4500 carboxysome proteins.
Icosahedric triangulation number is calculated following Caspar and Klug system
Physical principles in the construction of regular viruses
D. L. Caspar, A. Klug
Cold Spring Harb. Symp. Quant. Biol. 1962; 27: 1?24
D. L. Caspar, A. Klug
Cold Spring Harb. Symp. Quant. Biol. 1962; 27: 1?24