Interaction between DNA and Alpha/Beta-Type Small, Acid-Soluble Spore Proteins: ANew Class of DNA-Binding Protein

摘要

Approximately 5 to 10% of the protein in dormant spores of Bacillus andClostridium species is a group of small, acid-soluble proteins (SASP) of the alpha/beta type, which are coded for by multiple genes in all species examined. The amino acid sequences of alpha/beta-type SASP are very highly conserved both within and across species. Alpha/beta-type SASP are synthesized at about the third hour of sporulation only in the forespore compartment (37), and their synthesis parallels the acquisition of UV light resistance by the developing spore as well as a 50% increase in the number of negative supertwists in forespore plasmids. During spore germination, alpha/beta-type SASP are rapidly degraded to amino acids, with degradation initiated by a protease termed GPR, which is specific for SASP.