An alpha/beta-type, small, acid-soluble spore protein which has very high affinity for DNA prevents outgrowth of Bacillus subtilis spores.

A derivative of SspC, a minor alpha/beta-type, small, acid-soluble spore protein (SASP) from Bacillus subtilis, was generated that has a very high affinity for DNA. This protein (SspC(Delta11-D13K)) was able to confer UV resistance on spores lacking alpha/beta-type SASP, and spores with SspC(Delta11-D13K) triggered germination normally. However, SspC(Delta11-D13K) blocked outgrowth of > or = 90% of germinated spores, and SspC(Delta11-D13K) persisted in these germinated spores, whereas wild-type SspC was almost completely degraded. The outgrowth phenotype of spores with SspC(Delta11-D13K) is proposed to be due to the high stability of the SspC(Delta11-D13K)-DNA complex, which prevents rapid degradation of this alpha/beta-type SASP early in germination. The persistence of this protein on spore DNA then interferes with transcription during spore outgrowth.