Synthesis and degradation of the cyclic dinucleotide messenger c-di-AMP in the hyperthermophilic archaeon Pyrococcus yayanosii.

Cyclic di-adenosine monophosphate (c-di-AMP) is a newly identified prokaryotic cyclic dinucleotide second messenger well elucidated in bacteria, while less studied in archaea. Here, we describe the enzymes involved in c-di-AMP metabolism in hyperthermophilic archaeon Pyrococcus yayanosii. Our results demonstrate that c-di-AMP is synthesized from two molecules of ATP by diadenylate cyclase (DAC) and degraded into pApA and then to AMP by a DHH family phosphodiesterase (PDE). DAC can be activated by a wider variety of ions, using two conserved residues, D188 and E244, to coordinate divalent metal ions, which is different from bacterial CdaA and DisA. PDE possesses a broad substrate spectrum like bacterial DHH family PDEs, but shows a stricter base selection between A and G in cyclic dinucleotides hydrolysis. PDE shows differences in substrate binding patch from bacterial counterparts. C-di-AMP was confirmed to exist in Thermococcus kodakarensis cells, and the deletion of the dac or pde gene supports that the synthesis and degradation of c-di-AMP is catalysed by DAC and PDE, respectively. Our results provide further understanding of the metabolism of c-di-AMP in archaea. This article is protected by copyright. All rights reserved.