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Publication Abstract from PubMed

In the evolutionary arms race against phage, bacteria have assembled a diverse arsenal of antiviral immune strategies. While the recently discovered DISARM (Defense Island System Associated with Restriction-Modification) systems can provide protection against a wide range of phage, the molecular mechanisms that underpin broad antiviral targeting but avoiding autoimmunity remain enigmatic. Here, we report cryo-EM structures of the core DISARM complex, DrmAB, both alone and in complex with an unmethylated phage DNA mimetic. These structures reveal that DrmAB core complex is autoinhibited by a trigger loop (TL) within DrmA and binding to DNA substrates containing a 5' overhang dislodges the TL, initiating a long-range structural rearrangement for DrmAB activation. Together with structure-guided in vivo studies, our work provides insights into the mechanism of phage DNA recognition and specific activation of this widespread antiviral defense system.

Structural basis for broad anti-phage immunity by DISARM.,Bravo JPK, Aparicio-Maldonado C, Nobrega FL, Brouns SJJ, Taylor DW Nat Commun. 2022 May 27;13(1):2987. doi: 10.1038/s41467-022-30673-1. PMID:35624106^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.