Readthrough of the Bacillus subtilis stop codon produces an extended enzyme displaying a higher polymerase activity.

It has been generally accepted that the structural sacB gene of Bacillus subtilis levansucrase encodes a 50,000 Da extracellular protein. However, examination of the DNA sequence of the sacB flanking regions shows a putative open reading frame coding for a 20 amino acid peptide downstream immediately following the terminal TAA stop codon. By site-directed mutagenesis we have changed this stop codon to a glutamine codon.

Phosphoenolpyruvate:sugar phosphotransferase system of Bacillus subtilis: nucleotide sequence of ptsX, ptsH and the 5'-end of ptsI and evidence for a ptsHI operon.

The nucleotide sequence of a 1689bp fragment of the Bacillus subtilis locus containing ptsX (a crr-like gene), ptsH (coding for HPr), and the 5'-end of ptsI (coding for Enzyme I) was determined. The deduced amino acid sequences of ptsH and the N-terminal part of ptsI were compared to those of Streptococcus faecalis and Escherichia coli. Transcription fusion demonstrated that ptsHI constitutes an operon.