Competence operon G, ComGE (IPR020488)

Short name: Competence_ComGE

Overlapping homologous superfamilies


Family relationships



Competence is the ability of a cell to take up exogenous DNA from its environment, resulting in transformation. It is widespread among bacteria and is probably an important mechanism for the horizontal transfer of genes. DNA usually becomes available by the death and lysis of other cells. Competent bacteria use components of extracellular filaments called type 4 pili to create pores in their membranes and pull DNA through the pores into the cytoplasm. This process, including the development of competence and the expression of the uptake machinery, is regulated in response to cell-cell signalling and/or nutritional conditions [PMID: 8901420].

The development of genetic competence in Bacillus subtilis is a highly regulated adaptive response to stationary-phase stress. For competence to develop, the transcriptional regulator, ComK, must be activated. ComK is required for the expression of genes encoding proteins that function in DNA uptake. In log-phase cultures, ComK is inactive in a complex with MecA and ClpC. The comS gene is induced in response to high culture cell density and nutritional stress and its product functions to release active ComK from the complex. ComK then stimulates the transcription initiation of its own gene as well as that of the late competence operons [PMID: 10361283].

The comG operon of Bacillus subtilis encodes seven membrane associated proteins which function in binding of transforming DNA to the competent cell surface [PMID: 9723928]. ComGC, GD, GE and GG have N-terminal sequence motifs typical of type 4 pre-pilins and are processed by a pathway that requires the product of comC, also an essential competence gene. They form form pilin-like structures that are localised to the cytoplasmic membrane and cell wall [PMID: 9723928]. The comG operon also consist of ComGF, a small integral membrane protein, ComGA and ComGB, which are predicted to be a nucleotide binding protein and an integral membrane protein respectively [PMID: 2507524]. When strains missing each of the 7 proteins are created, they were all found to be nontransformable and failed to bind transforming DNA to the cell surface [PMID: 9422590].

ComGE, or Protein 5, is one of seven proteins encoded by the comG operon of B. subtilis. The unprocessed form of protein 5 is an integral membrane protein. Upon cleavage, it is translocated to the outer face of the membrane [PMID: 9723928].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.