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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. ==Discovery== See: discovery of carboxysomes The first BMCs were observed in the 1950s in electron micrographs of cyanobacteria,〔 and were later named carboxysomes after their role in carbon fixation was established.〔 Until the 1990s, carboxysomes were thought to be an oddity confined to certain autotrophic bacteria. But then genes coding for proteins homologous to those of the carboxysome shell were identified in the ''pdu'' (propanediol utilization)〔 and ''eut'' (ethanolamine utilization)〔 operons. Subsequently, transmission electron micrographs of ''Salmonella'' cells grown on propanediol 〔 or ethanolamine 〔 showed the presence of polyhedral bodies similar to carboxysomes. The term metabolosome is used to refer to such catabolic BMCs (in contrast to the autotrophic carboxysome). Although the carboxysome, propanediol utilizing (PDU), and ethanolamine utilizing (EUT) BMCs encapsulate different enzymes and therefore have different functions, the genes encoding for the shell proteins are very similar. Most of the genes (coding for the shell proteins and the encapsulated enzymes) from experimentally characterized BMCs are located near one another in distinct genetic loci or operons. There are currently over 20,000 bacterial genomes sequenced, and bioinformatics methods can be used to find all BMC shell genes and to look at what other genes are in the vicinity, producing a list of potential BMCs.〔〔〔〔 Recently a comprehensive survey identified 23 different loci encoding up to 10 functionally distinct BMCs across 23 bacterial phyla.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bacterial microcompartment」の詳細全文を読む スポンサード リンク
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