The nucleotide sequence of 3 kb of Bacillus subtilis chromosomal DNA, including sacS, reveals that the regulatory locus for levansucrase synthesis consists of two genes, sacX and sacY. The sacX gene product is remarkably similar to sucrose-specific enzyme II of the B. subtilis phosphoenolpyruvate-dependent phosphotransferase system. The product of sacY is similar, both in amino acid sequence and most probably in its function, to BglG, an Escherichia coli transcriptional antitermination factor.