Major carboxysome shell protein CsoS1A

UniProtKB accession:  P45689

Grouped By:  Matching UniProtKB accession

UniProtKB description:  The major shell protein of the carboxysome, a polyhedral inclusion where RuBisCO (ribulose bisphosphate carboxylase, ccbL-ccbS) is sequestered (PubMed:7934888, PubMed:16535117). Assembles into hexamers which make sheets that form the facets of the polyhedral carboxysome (PubMed:17518518). The shell probably limits the diffusion of CO(2) into and out of the carboxysome (Probable). Molecular modeling shows the central pore of this protein is selectively permeable to anions such as HCO(3) rather than CO(2) or O(2) (Probable). There are estimated to be 2970 CsoS1A/CsoS1C proteins per carboxysome (the proteins differ by only 1 residue) (Ref.5).