Antiviral cyclic nucleotides and oligonucleotides are utilized by various organisms for innate immune signaling; in humans, these molecules activate the STING-dependent interferon pathway, whereas bacteria utilize ancestral cGAS/DncV-like nucleotidyltransferases (CD-NTases) to fight bacteriophage infection. Although the molecular basis of eukaryotic innate immune signaling is known, details of its bacterial counterpart are less well established. Ledvina et al. have now used cryo-electron microscopy to determine the structure of a complex between a CD-NTase and an associated protein (Cap2) that provides insight into the mechanism of activation.

抗病毒环核苷酸和寡核苷酸被各种生物体用于先天免疫信号；在人类中，这些分子激活 STING 依赖性干扰素通路，而细菌利用祖先的 cGAS/DncV 样核苷酸转移酶 (CD-NTases) 来对抗噬菌体感染。虽然真核先天免疫信号的分子基础是已知的，但其细菌对应物的细节还不太清楚。莱德维纳等人。现在已经使用冷冻电子显微镜来确定 CD-NTase 和相关蛋白 (Cap2) 之间复合物的结构，从而深入了解激活机制。