pfam10635: DisA-linker (This model is not part of the current CDD release)
DisA bacterial checkpoint controller linker region
The DisA protein is a bacterial checkpoint protein that dimerizes into an octameric complex. The protein consists of three distinct domains. the first, N-terminal region, from 1-145 is globular and is represented by family DisA_N, pfam02457; the next 146-289 residues is this domain that consists of an elongated bundle of three alpha helices (alpha-6, alpha-10, and alpha-11), one side of which carries an additional three helices (alpha7-9), thus forming a spine like-linker between domains 1 and 3. The C-terminal residues of domain 3 are family HHH, pfam00633, the specific DNA-binding domain. The octameric complex thus has structurally linked nucleotide-binding and DNA-binding HhH domains and the nucleotide-binding domains are bound to a cyclic di-adenosine phosphate such that DisA is a specific di-adenylate cyclase. The di-adenylate cyclase activity is strongly suppressed by binding to branched DNA, but not to duplex or single-stranded DNA, suggesting a role for DisA as a monitor of the presence of stalled replication forks or recombination intermediates via DNA structure-modulated c-di-AMP synthesis.
Jiyao W et al.(2023). "The conserved domain database in 2023.",