Acid-soluble spore proteins of Bacillus subtilis

Abstract

Acid-soluble spore proteins (ASSP) comprise about 5% of the total protein of mature spores of different B. subtilis strains. They consist of 3 abundant species, .alpha., .beta. and .gamma., 4 less abundant species, and several minor species. .alpha.,.beta. and .gamma. make up about 18, 18 and 36%, respectively, of the total ASSP of strain 168, have MW of 5900,5900 and 11,000, respectively, and resemble the major (A, C and B) components of B. megaterium ASSP in several respects, including sensitivity to a specific B. megaterium spore endopeptidase. The B. subtilis .alpha.,.beta. and .gamma. proteins have isoelectric points of 6.58, 6.67 and 7.96, respectively all lower than those of any B. megaterium ASSP. Although strains varied in the proportions of different located interior to the cortex, presumably in the spore cytoplasm, and are synthesized during sporulation and degraded during germination.