One of 3 paralogous diadenylate cyclases (DAC) in this bacteria, catalyzing the condensation of 2 ATP molecules into cyclic di-AMP (c-di-AMP) (Probable). Upon expression in E.coli leads to c-di-AMP synthesis (PubMed:23192352, PubMed:24939848). Overexpression of the hyperactive mutant (L44F) in the absence of c-di-AMP phosphodiesterase GdpP leads to growth defects in log phase (long curly cell filaments) that disappear upon sporulation; spore formation is normal, showing sporulation is insensitive to the excess c-di-AMP (PubMed:23192352). In B.subtilis c-di-AMP is a second messenger that mediates growth, DNA repair and cell wall homeostasis; it is toxic when present in excess. 2 ATP = 3',3'-c-di-AMP + 2 diphosphate Forms dimers and probably also hexamers; the dimer may be active while the hexamer may not be active. Probably expressed only during sporulation in the forespore. Expressed under control of the sigma-G factor in the forespore. The N-terminus (residues 1-69) is thought to form 2 alpha-helices that allow dimerization and probable hexamerization; this region inhibits DAC activity of the rest of the protein (PubMed:24939848). No effect on antibiotic sensitivity to the beta-lactam antibiotic cefuroxime (CEF), upon overexpression of the c-di-AMP phosphodiesterase GdpP increased sensitivity to CEF (PubMed:22211522). Double disA-cdaA mutants cannot be made, suggesting they are lethal, while double disA-cdaS and cdaA-cdsS mutants are viable (PubMed:22211522, PubMed:23192352). In single deletions of this gene, germination efficiency is decreased (PubMed:24939848). Belongs to the adenylate cyclase family. DacB/CdaS subfamily. Truncated N-terminus.