Protein Domain : Bacterial HORMA domain IPR040649

Type	Domain
Description	This entry represents the HORMA domain found in bacterial proteins from the cyclic-oligonucleotide-based anti-phage signalling system (CBASS), such us CD-NTase-associated protein 7 from Pseudomonas aeruginosa (Cap7, also known as Bacterial HORMA2 sensor protein), which is part of the type III-CBASS. CBSSs are a family of defence systems against bacteriophages which are ancestry related with the cGAS-STING innate immune pathway in animals. CBASSs are composed of an oligonucleotide cyclase, which generates signalling cyclic oligonucleotides in response to phage infection, and an effector that is activated by the cyclic oligonucleotides and promotes cell death [ , ]. Cap7 is essential for phage defence and it is the sensor protein in the type III-CBASS. It binds to a closure peptide (consensus Glu-Val-Met-Glu-Phe-Asn-Pro), and forms the CdnD:Cap7:Cap8 complex, which allows it to activate the oligonucleotide cyclase CdnD for second messenger synthesis. The oligonucleotide cyclase becomes active only when physically bound by the HORMA-domain protein [].
Short Name	Bact_HORMA