comF, a Bacillus subtilis late competence locus, encodes a protein similar to ATP-dependent RNA/DNA helicases

Mol Microbiol. 1993 Jul;9(1):119-31. doi: 10.1111/j.1365-2958.1993.tb01674.x.


We have sequenced and genetically characterized comF, a Bacillus subtilis competence locus, previously identified by Tn917 transposon insertion mutagenesis. Expression of the locus, in which three open reading frames (ORFs) were found, is driven by a single sigma A-like promoter in front of comFORF1 and is dependent on early regulatory competence genes and only expressed in competence medium. The predicted amino acid sequences of two of the ORFs showed similarities to known proteins in the GenBank and SwissProt databases: ComFORF1 is similar to an extensive family of ATP-dependent RNA/DNA helicases with closer similarity to the DEAD protein subfamily and to the PriA protein in Escherichia coli. The latter is a DNA translocase/helicase required for primosome assembly at the replication fork of phage phi X174. ComFORF3 is 22% identical to Com101, a protein required for genetic competence in Haemophilus influenzae, a naturally competent Gram-negative bacterium. In-frame comFORF1 deletions were 1000-fold deficient in transformability compared to the wild-type, whereas disruptions of the other two ORFs were only five- to 10-fold lower. These observations allow us to hypothesize that the ComFORF1 late gene product plays an essential role during the binding and uptake events involved in Bacillus subtilis transformation.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphatases / genetics*
  • Amino Acid Sequence
  • Bacillus subtilis / genetics*
  • Bacterial Proteins / genetics*
  • Base Sequence
  • Consensus Sequence
  • DNA Helicases*
  • DNA-Binding Proteins*
  • Escherichia coli Proteins
  • Genes, Bacterial*
  • Haemophilus influenzae / genetics
  • Molecular Sequence Data
  • Open Reading Frames
  • Promoter Regions, Genetic
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Species Specificity
  • Transformation, Bacterial / genetics*


  • Bacterial Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • comF1 protein, Bacillus subtilis
  • comF3 protein, Bacillus subtilis
  • Adenosine Triphosphatases
  • priA protein, E coli
  • DNA Helicases

Associated data

  • GENBANK/Z18629