title: Crystal protein formed by Bacillus subtilis cells.
abstract: Electron microscopic investigation of ultrathin sections of Bacillus subtilis Cgr4 cells revealed the presence of crystal-like inclusions which were formed of spheric homogeneous subunits. The frequency of cells with a crystal-like inclusion in the culture approached 1%. The appearance of the crystal protein in cells coincided in time with spore morphogenesis. However, the process of crystal protein formation and sporulation are two alternatives: the cells either form the crystal protein or continue spore morphogenesis. Fractionation of cells in the stationary growth phase on a Percoll density gradient showed that the cells containing the crystal protein accumulated in the fraction corresponding to a 1.14-g/ml Percoll density. The cells were disintegrated by sonication, and alkaline-extracted proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After sodium dodecyl sulfate-gel electrophoresis, the fraction enriched with crystal-containing cells showed practically a single band with a molecular weight of 47,000 that corresponded to the crystal-forming protein. The antigenic features and amino acid composition indicated certain similarities between the crystal-forming protein in B. subtilis Cgr4 cells and the spore coat protein.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001412:Bacillus subtilis / Q000378:metabolism / Q000648:ultrastructure*; D001426:Bacterial Proteins / Q000032:analysis*; D003460:Crystallization; D008854:Microscopy, Electron; D008970:Molecular Weight
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; C053999:crystal protein, Bacillus subtilis