Structural insights into signaling promiscuity of the CBASS anti-phage defense system from a radiation-resistant bacterium.
Yang, C.S., Shie, M.Y., Huang, S.W., Wang, Y.C., Hou, M.H., Chen, C.J., Chen, Y.(2025) Int J Biol Macromol 295: 139534-139534
- PubMed: 39761885
- DOI: https://doi.org/10.1016/j.ijbiomac.2025.139534
- Primary Citation of Related Structures:
8YSC, 8YSD, 8YSE, 8YSG, 8YSI, 8YSJ, 8YSK, 8YSL, 8YSM, 8YSN, 8YSO, 8YSQ, 8YSR, 8YSS, 8YSU - PubMed Abstract:
Radiation-resistant bacteria are of great application potential in various fields, including bioindustry and bioremediation of radioactive waste. However, how radiation-resistant bacteria combat against invading phages is seldom addressed. Here, we present a series of crystal structures of a sensor and an effector of the cyclic oligonucleotide-based anti-phage signaling system (CBASS) from a radioresistant bacterium Deinococcus wulumuqiensis. We found that the sensor CD-NTase enzyme, DwCdnB, can bind all four ribonucleotides and synthesize a variety of cyclic di-nucleotides, including the novel second messenger 3'3'-cyclic di-CMP. Crystal structures of DwCdnB in complex with ATP and dATP provide structural explanations for specific recognition of ribonucleotides via metal coordination with ribose 2'-OH. Crystal structures of DwCdnB in complex with purine and/or pyrimidine nucleotides in the presence of Mg 2+ revealed similar binding modes; however, in the presence of Mn 2+ , the UTP/CTP rotates and flips into the donor pocket and make extensive contacts with additional five residues, suggesting essential role of Mn 2+ for catalytic production of cyclic di-pyrimidines. Finally, structural analysis of the downstream effector DwCap5 further provides a structural explanation for its non-specific recognition of a broad range of cyclic di-nucleotides. In sum, this work provides key structural insights into the immune mechanisms of radioresistant bacteria.
Organizational Affiliation:
Department of Food Science and Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan.