This entry represents an alpha-hairpin found at the N-terminal of Diadenylate cyclase CdaS. CdaS is one of 3 paralogous diadenylate cyclases (DAC) in Bacillus subtilis and B. thuringiensis, catalysing he condensation of 2 ATP molecules into cyclic di-AMP (c-di-AMP). It has slow DAC activity with ADP as a substrate and may have weak ADPase activity [1]. CdaS is required for efficient spore formation in B.thuringiensis, whereas in B.subtilis, it is required for efficient spore germination. It is produced under the control of different sigma factors in the two bacteria. It is also required for parasporal crystal formation [1-3].

1: Functional analysis of the sporulation-specific diadenylate cyclase CdaS in Bacillus thuringiensis. Zheng C, Ma Y, Wang X, Xie Y, Ali MK, He J; Front Microbiol. 2015;6:908. PMID:26441857

2: Control of the diadenylate cyclase CdaS in Bacillus subtilis: an autoinhibitory domain limits cyclic di-AMP production. Mehne FM, Schroder-Tittmann K, Eijlander RT, Herzberg C, Hewitt L, Kaever V, Lewis RJ, Kuipers OP, Tittmann K, Stulke J; J Biol Chem. 2014;289:21098-21107. PMID:24939848

3: Cyclic di-AMP homeostasis in bacillus subtilis: both lack and high level accumulation of the nucleotide are detrimental for cell growth. Mehne FM, Gunka K, Eilers H, Herzberg C, Kaever V, Stulke J; J Biol Chem. 2013;288:2004-2017. PMID:23192352