Cover image

Type III toxin–antitoxin complex (PDB id: 7D8O; Manikandan P, Sandhya S, Nadig K, Paul S, Srinivasan N, Rothweiler U, Singh M. 2022. Identification, functional characterization, assembly and structure of ToxIN type III toxin–antitoxin complex from E. coli. Nucleic Acids Res 50: 1687–1700). Toxin–antitoxin (TA) systems are proposed to play crucial roles in bacterial growth under stress conditions such as phage infection. Type III TA systems consist of a protein toxin whose activity is inhibited by a noncoding RNA antitoxin. The toxin, an endoribonuclease, forms a high-affinity complex with antitoxin RNA resulting from two independent (5' and 3' sides of RNA) RNA binding sites on the protein. Antitoxin RNA is displayed using NDB colors: A—red, C—yellow, G—green, U—cyan; the endoribonuclease toxin is displayed in gray. Cover image provided by the Nucleic Acid Database (NDB)/Nucleic Acid Knowledgebase (NAKB; nakb.org). Image was created using Mol* (Sehnal D, Bittrich S, Deshpande M, Svobodová R, Berka K, Bazgier V, Velankar S, Burley SK, Koča J, Rose AS. 2021. Nucleic Acids Res 49: W431–W437).