J. Biol. Chem., Vol. 260, Issue 6, 3368-3372, Mar, 1985
Bacillus subtilis dnaE encodes a protein homologous to DNA primase of Escherichia coli
LF Wang, CW Price and RH Doi
Bacillus subtilis dnaE encodes a protein essential for DNA replication and
is tightly linked to rpoD, the gene for the major sigma factor of RNA
polymerase. We have now determined the 1809-base pair sequence of the dnaE
coding region, which precedes rpoD and is transcribed in the same
counterclockwise direction on the chromosome. From the DNA sequence, we
found that the dnaE protein comprised 603 amino acids with a calculated
molecular mass of 68,428 daltons. This protein had significant and
extensive regions of homology with Escherichia coli DNA primase, the
polymerase that synthesizes short RNA primers during discontinuous DNA
replication. Features of the coding and flanking regions that may modulate
dnaE expression include a relatively weak ribosomal binding site (delta G'
= -13.8 kcal), the use of uncommon codons in the reading frame, and no
obvious promoter sequence for either dnaE or rpoD. Together, these results
suggest that dnaE codes for B. subtilis DNA primase and, in light of the
similarities to the organization of the E. coli sigma operon, that
expression of dnaE may be coregulated with rpoD in B. subtilis.