Purification and properties of some unique low molecular weight basic proteins degraded during germination of Bacillus megaterium spores.
Two major proteins, termed proteins A and B, and one minor species, termed protein C, have been purified to homogeneity from dilute acid extracts of dormant spores of Bacillus megaterium. These three species comprise approximately 80% of the protein in the dilute acid extracts and account for 60 to 75% of the protein degraded during spore germination. All three proteins have low molecular weights (7,000 to 10,000), high isoelectric points (greater than 9.8), alanine as the NH2-terminal amino acid, are more hydrophilic than most proteins, and all lack cysteine, cystine, and tryptophan. In addition all three proteins are extremely sensitive to a wide variety of proteolytic enzymes, much more so than "average" proteins such as serum albumin, lysozyme, and hemoglobin. These proteins also bind to both purified DNA and to a nuclear body from dormant spores. Although this binding gives little or no protection to proteins A and B from proteolysis, it does result in elevation of the melting temperature of the DNA by as much as 20degrees.
D000596:Amino Acids / Q000032:analysis; D001410:Bacillus megaterium / Q000378:metabolism*; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004247:DNA; D008970:Molecular Weight; D009691:Nucleic Acid Denaturation; D010447:Peptide Hydrolases; D011485:Protein Binding; D011489:Protein Denaturation; D013056:Spectrophotometry, Ultraviolet; D013171:Spores, Bacterial / Q000378:metabolism
D000596:Amino Acids; D001426:Bacterial Proteins; D004247:DNA; D010447:Peptide Hydrolases