Small, Acid-Soluble Proteins Bound to DNA Protect Bacillus subtilis Spores fromKilling by Dry Heat

摘要

Dry Bacillus subtilis spores lacking their two major DNA-binding proteins (small,acid-soluble proteins SASPi a and I) 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 a and % provide significant protection to spore DNA against the damaging effects of dry heat. This DNA damage may be in part depurination, and a purified a/j3-type SASP gave significant protection against dry heat-induced DNA depurination in vitro.