PROSITE documentation PDOC00276

Small, acid-soluble spore proteins, alpha/beta type, signatures

Small, acid-soluble spore proteins (SASP or ASSP) [1,2] are proteins found in the spores of bacteria of the genera Bacillus, Thermoactynomycetes, and Clostridium. SASP are bound to spore DNA. They are double-stranded DNA-binding proteins that cause DNA to change to an A-like conformation. They protect the DNA backbone from chemical and enzymatic cleavage and are thus involved in dormant spore's high resistance to UV light. SASP are degraded in the first minutes of spore germination and provide amino acids for both new protein synthesis and metabolism.

There are two distinct families of SASP: the α/β type and the γ-type. α/β SASP are small proteins of about sixty to seventy amino acid residues. They are generally coded by a multigene family. Two regions of α/β SASP are particularly well conserved: the first region is located in the N-terminal half and contains the site which is cleaved by a SASP-specific protease that acts during germination; the second region is located in the C-terminal section and is probably involved in DNA-binding. We selected both regions as signature patterns for these proteins.