Bacterial microcompartment
（重定向自Microcompartments）
![Stylized view of the carboxysome and related bacterial structures such as the propanediol utilization (Pdu) and ethanolamine utilization (Eut) microcompartments. Distinct hexameric BMC shell proteins carrying out different functions in the shell are shown in different shades of blue. Pentameric vertex proteins are shown in magenta. Encapsulated enzymes are shown in green, organized in layers. [Image: T. Yeates](/Images/godic/202501/27/Carboxysome_and_bacterial_microcompartments5841.jpg")
![The three types of proteins (BMC-H, BMC-T and BMC-P) known to form the shell of BMCs. The encapsulated enzymes/proteins (shown in purple, red and turquoise) constitute a metabolic reaction sequence. (Image credit: Seth Axen, Markus Sutter, Sarah Newnham, Clement Aussignargues and Cheryl Kerfeld)](/Images/godic/202501/27/The_three_types_of_BMC_shell_proteins5841.jpeg")
![Generalized function schematic for experimentally characterized BMCs. (A) Carboxysome. (B) Metabolosome. Reactions in gray are peripheral reactions to the core BMC chemistry. BMC shell protein oligomers are depicted on the left: blue, BMC-H; cyan, BMC-T; yellow, BMC-P. 3-PGA, 3-phosphoglycerate, and RuBP, ribulose 1,5-bisphosphate.[20]](/Images/godic/202501/27/Generalized_function_schematic_for_experimentally_characterized_BMCs5841.jpeg")
![Electron micrographs showing alpha-carboxysomes from the chemoautotrophic bacterium Halothiobacillus neapolitanus: (A) arranged within the cell, and (B) intact upon isolation. Scale bars indicate 100 nm.[21]](/Images/godic/202501/27/Carboxysomes_EM5841.jpg")
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Bacterial Microcompartments (BMCs) are organelles consisting of a protein shell that encloses enzymes and other proteins. BMCs are typically about 40-200 nanometers in diameter and are entirely made of proteins. The shell functions like a membrane, as it is selectively permeable. Other protein-based compartments found in bacteria and archaea include encapsulin nanocompartments and gas vesicles. Eukaryotes have also been observed to have proteinaceous organelles, such as the mysterious vault complex.