Protein Domain : Carboxysome shell protein CcmK IPR046380

Type	Family
Description	Bacterial microcompartments (BMCs) are large proteinaceous structures comprised of a roughly icosahedral shell and a series of encapsulated enzymes. They are found across bacteria where they play functionally diverse roles including CO(2) fixation and the catabolism of a range of organic compounds. They function as organelles by sequestering particular metabolic processes within the cell. A shell or capsid, which is composed of a few thousand protein subunits, surrounds a series of sequentially acting enzymes and controls the diffusion of substrates and products (including toxic or volatile intermediates) into and out of the lumen. Although functionally distinct BMCs vary in their encapsulated enzymes, all are defined by homologous shell proteins. The shells of BMCs are made primarily of a family of proteins whose structural core is the BMC domain, and variations upon this core provide functional diversity [ , , ]. This entry represents Carboxysome shell protein CcmK and similar proteins from cyanobacteria. CcmK is one of the shell proteins of the carboxysome, a polyhedral BMC where RuBisCO (ribulose bisphosphate carboxylase) is sequestered for primary carbon production. It assembles into hexamers which make sheets that form the facets of the polyhedral carboxysome [ , ]. The formation of hexamers might play a role in environmental adaptability [].
Short Name	CcmK