Ribosomal stalk-captured CARF-RelE ribonuclease inhibits translation following CRISPR signaling

• 成果类型: Article
• 署名作者: Mogila, Irmantas; Tamulaitiene, Giedre; Keda, Konstanty; Timinskas, Albertas; Ruksenaite, Audrone; Sasnauskas, Giedrius; Venclovas, Ceslovas; Siksnys, Virginijus; Tamulaitis, Gintautas
• 署名单位: Vilnius University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-11466
• DOI: 10.1126/science.adj2107
• 发表日期: 2023-12-01
• 页码: 1036-1041
• 关键词: elongation-factor-g; multiple sequence alignment; bacterial toxin rele; cryo-em structure; structural basis; protein l7/l12; ef-g; cleavage; complex; tool

摘要

Prokaryotic type III CRISPR-Cas antiviral systems employ cyclic oligoadenylate (cA(n)) signaling to activate a diverse range of auxiliary proteins that reinforce the CRISPR-Cas defense. Here we characterize a class of cA(n)-dependent effector proteins named CRISPR-Cas-associated messenger RNA (mRNA) interferase 1 (Cami1) consisting of a CRISPR-associated Rossmann fold sensor domain fused to winged helix-turn-helix and a RelE-family mRNA interferase domain. Upon activation by cyclic tetra-adenylate (cA(4)), Cami1 cleaves mRNA exposed at the ribosomal A-site thereby depleting mRNA and leading to cell growth arrest. The structures of apo-Cami1 and the ribosome-bound Cami1-cA(4) complex delineate the conformational changes that lead to Cami1 activation and the mechanism of Cami1 binding to a bacterial ribosome, revealing unexpected parallels with eukaryotic ribosome-inactivating proteins.