This entry includes the catalytic domain of the protein ImmA, which is a metallopeptidase containing an HEXXH zinc-binding motif from peptidase family M78. ImmA is encoded on a conjugative transposon. Conjugating bacteria are able to transfer conjugative transposons that can, for example, confer resistance to antibiotics. The transposon is integrated into the chromosome, but during conjugation excises itself and then moves to the recipient bacterium and re-integrate into its chromosome. Typically a conjugative tranposon encodes only the proteins required for this activity and the proteins that regulate it. During exponential growth, the ICEBs1 transposon of Bacillus subtilis is inactivated by the immunity repressor protein ImmR, which is encoded by the transposon and represses the genes for excision and transfer. Cleavage of ImmR relaxes repression and allows transfer of the transposon. ImmA has been shown to be essential for the cleavage of ImmR [2]. This domain is also found in in metalloprotease IrrE, a central regulator of DNA damage repair in Deinococcaceae [1], HTH-type transcriptional regulators RamB [3] and PrpC [4].

1: Crystal structure of the IrrE protein, a central regulator of DNA damage repair in deinococcaceae. Vujicic-Zagar A, Dulermo R, Le Gorrec M, Vannier F, Servant P, Sommer S, de Groot A, Serre L; J Mol Biol. 2009;386:704-716. PMID:19150362

2: A conserved anti-repressor controls horizontal gene transfer by proteolysis. Bose B, Auchtung JM, Lee CA, Grossman AD; Mol Microbiol. 2008;70:570-582. PMID:18761623

3: RamB, a novel transcriptional regulator of genes involved in acetate metabolism of Corynebacterium glutamicum. Gerstmeir R, Cramer A, Dangel P, Schaffer S, Eikmanns BJ; J Bacteriol. 2004;186:2798-2809. PMID:15090522

4: A novel role of the PrpR as a transcription factor involved in the regulation of methylcitrate pathway in Mycobacterium tuberculosis. Masiewicz P, Brzostek A, Wolanski M, Dziadek J, Zakrzewska-Czerwinska J; PLoS One. 2012;7:e43651. PMID:22916289