Small, acid-soluble proteins bound to DNA protect Bacillus subtilis spores from killing by dry heat

Abstract

Dry Bacillus subtilis spores lacking their two major DNA-binding proteins (small, acid-soluble proteins [SASP] α and β) were much more sensitive to dry heat than were wild-type spores. Survivors of dry heat treatment of both wild-type and mutant spores exhibited a high frequency of mutations, and the DNA from the heated spores had increased numbers of single-strand breaks. These data indicate that SASP α and β provide significant protection to spore DNA against the damaging effects of dry heat. This DNA damage may be in part depurination, and a purified α/β-type SASP gave significant protection against dry heat-induced DNA depurination in vitro.