Bacillus subtilis spore coats: complexity and purification of a unique polypeptide component.
Extensively washed, dormant spores of Bacillus subtilis were disrupted with glass beads in buffer at pH 7 in the presence of protease inhibitors. Approximately 31% of the total spore protein was soluble, and another 14% was removed from the insoluble fraction by hydrolysis with lysozyme and washing with 1 M KCl and 0.1% sodium dodecyl sulfate. The residual spore integuments comprised 55% of the total spore proteins and consisted of coats and residual membrane components. Treatment of integuments with sodium dodecyl sulfate and reducing agents at pH 10 solubilized 40% of the total spore protein. Seven low-molecular-weight polypeptide components of this solubilized fraction comprised 27% of the total spore protein. They are not normal membrane components and reassociated to form fibrillar structures resembling spore coat fragments. The residual insoluble material (15% of the total spore protein) was rich in cysteine and was probably also derived from the spore coats. A solubilized coat polypeptide of molecular weight 12,200 has been purified in good yield (4 to 5% of the total spore protein). Five amino acids account for 92% of its total amino acid residues: glycine, 19%; tyrosine, 31%; proline, 23%; arginine, 13%; and phenylalanine, 6%.
D000596:Amino Acids / Q000032:analysis; D001412:Bacillus subtilis / Q000032:analysis* / Q000502:physiology; D001426:Bacterial Proteins / Q000032:analysis* / Q000302:isolation & purification; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis; D013171:Spores, Bacterial / Q000032:analysis*; D014443:Tyrosine / Q000032:analysis
D000596:Amino Acids; D001426:Bacterial Proteins; D010455:Peptides; D014443:Tyrosine