Secretory S complex of Bacillus subtilis forms a large, organized structure when released from ribosomes.
The S complex of Bacillus subtilis, a set of four proteins that appears to be involved in protein secretion, is shown to be attached to 70S ribosomes: antibody to its 64-kDa component can aggregate these ribosomes, and the complex can be chemically crosslinked to ribosomal proteins. Low Mg2+ or prolonged high-speed centrifugation in a sucrose gradient releases the S complex from the ribosomes, and it is recovered as an aggregate with an S value of 76. Electron microscopy shows that these aggregates have a regular structure, somewhat resembling clathrin cages, with a diameter of about 45 nm. If these aggregates are physiological, their function would differ significantly from that of the signal recognition particle of eukaryotes.
D001412:Bacillus subtilis / Q000378:metabolism* / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism; D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D008970:Molecular Weight; D011485:Protein Binding; D012270:Ribosomes / Q000378:metabolism*
D001426:Bacterial Proteins; D002966:Clathrin; D003432:Cross-Linking Reagents; D046911:Macromolecular Substances