Identification of DNA-binding proteins changed after induction of sporulation in Bacillus cereus

DNA-binding proteins were extracted from both exponentially growing cells of Bacillus cereus ts-4 and cells that were induced to sporulate at different stages of chromosome replication, by using a double-stranded B. cereus ts-4 DNA-cellulose column. Two-dimensional electrophoresis of the proteins found that the amounts of 17 proteins changed drastically after induction of sporulation at all the stages. For 8 of those proteins, the largest or the smallest amount was found in the cells which were induced to sporulate 40 min after the initiation of chromosome replication, the sensitive stage for sporulation. The N-terminal amino acids of 6 proteins among the selected proteins were sequenced. The sequence obtained from a 59-kDa protein had sequence similarity (> 45%) to GroEL from several bacterial species. In addition, the sequences from 76- and 52-kDa proteins matched deduced amino acid sequences of a Mycobacterium leprae gene showing homology to the bacteria atp operon and the B. subtilis guaB for IMP dehydrogenase, respectively.