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 the 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 patches 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 are catalyzed by DAC and PDE, respectively. Our results provide a further understanding of the metabolism of c-di-AMP in archaea.

中文翻译：

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超嗜热古菌 Pyrococcus yayanosii 中环状二核苷酸信使 c-di-AMP 的合成和降解

环二腺苷单磷酸（c-di-AMP）是一种新发现的原核环二核苷酸第二信使，在细菌中得到了很好的阐明，但在古细菌中研究较少。在这里，我们描述了超嗜热古菌Pyrococcus yayanosii中参与 c-di-AMP 代谢的酶。我们的结果表明，c-di-AMP 是通过二腺苷酸环化酶 (DAC) 从两分子 ATP 合成的，并通过 DHH 家族磷酸二酯酶 (PDE) 降解为 pApA，然后降解为 AMP。DAC可以被更广泛的离子激活，利用两个保守残基D188和E244来配位二价金属离子，这与细菌CdaA和DisA不同。PDE 与细菌 DHH 家族 PDE 一样具有广泛的底物谱，但在环状二核苷酸水解中显示出 A 和 G 之间更严格的碱基选择。PDE 显示底物结合斑块与细菌对应物的差异。C-di-AMP被证实存在于Thermococcus kodakarensis细胞中，并且dac或pde基因的缺失支持c-di-AMP的合成和降解分别由DAC和PDE催化。我们的结果提供了对古细菌中 c-di-AMP 代谢的进一步了解。