Identification of in vivo substrates of the chaperonin GroEL from Bacillus subtilis

We investigated GroEL substrates from Bacillus subtilis 168 using the single-ring mutant of B. subtilis GroEL. We identified 28 candidates for GroEL substrates, of which Spo0B, Ald, Eno, SpoIIP, and FbaA were involved in spore formation, and Rnc, Tuf, Eno, Tsf, and FbaA were essential for B. subtilis growth. As observed at the protein level, the amount of SpoIIP interaction with GroEL increased at 3 h after initiation of sporulation.