ComEA, a Bacillus subtilis integral membrane protein required for genetic transformation, is needed for both DNA binding and transport.
The competence-related phenotypes of mutations in each of the four open reading frames associated with the comE locus of Bacillus subtilis are described. comEA and comEC are required for transformability, whereas the products of comEB and of the overlapping comER, which is transcribed in the reverse direction, are dispensable. Loss of the comEA product decreases the binding of DNA to the competent cell surface and the internalization of DNA, in addition to exhibiting a profound effect on transformability. The comEC product is required for internalization but is dispensable for DNA binding. ComEA is shown to be an integral membrane protein, as predicted from hydropathy analysis, with its C-terminal domain outside the cytoplasmic membrane. This C-terminal domain possesses a sequence with similarity to those of several proteins known to be involved in nucleic acid transactions including UvrC and a human protein that binds to the replication origin of the Epstein-Barr virus.
Inamine
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GS
Public Health Research Institute, New York, New York 10016, USA.
Dubnau
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D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005798:Genes, Bacterial; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009876:Operon; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014170:Transformation, Genetic
D001426:Bacterial Proteins; C093807:ComEA protein, Bacillus subtilis; D004268:DNA-Binding Proteins; D008565:Membrane Proteins