Structure and Mechanism of a Cyclic Trinucleotide-Activated Bacterial Endonuclease Mediating Bacteriophage Immunity

Rebecca K Lau; Qiaozhen Ye; Erica A Birkholz; Kyle R Berg; Lucas Patel; Ian T Mathews; Jeramie D Watrous; Kaori Ego; Aaron T Whiteley; Brianna Lowey; John J Mekalanos; Philip J Kranzusch; Mohit Jain; Joe Pogliano; Kevin D Corbett

doi:10.1016/j.molcel.2019.12.010

Structure and Mechanism of a Cyclic Trinucleotide-Activated Bacterial Endonuclease Mediating Bacteriophage Immunity

Mol Cell. 2020 Feb 20;77(4):723-733.e6. doi: 10.1016/j.molcel.2019.12.010. Epub 2020 Jan 10.

Authors

Affiliations

¹ Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA.
² Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.
³ Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.
⁴ Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Chemistry, University of California, San Diego, La Jolla, CA, USA.
⁵ Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA; Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA; Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
⁶ Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA; Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
⁷ Department of Microbiology, Harvard Medical School, Boston, MA, USA; Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA.
⁸ Department of Microbiology, Harvard Medical School, Boston, MA, USA.
⁹ Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Chemistry, University of California, San Diego, La Jolla, CA, USA; Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA. Electronic address: kcorbett@ucsd.edu.

Abstract

Bacteria possess an array of defenses against foreign invaders, including a broadly distributed bacteriophage defense system termed CBASS (cyclic oligonucleotide-based anti-phage signaling system). In CBASS systems, a cGAS/DncV-like nucleotidyltransferase synthesizes cyclic di- or tri-nucleotide second messengers in response to infection, and these molecules activate diverse effectors to mediate bacteriophage immunity via abortive infection. Here, we show that the CBASS effector NucC is related to restriction enzymes but uniquely assembles into a homotrimer. Binding of NucC trimers to a cyclic tri-adenylate second messenger promotes assembly of a NucC homohexamer competent for non-specific double-strand DNA cleavage. In infected cells, NucC activation leads to complete destruction of the bacterial chromosome, causing cell death prior to completion of phage replication. In addition to CBASS systems, we identify NucC homologs in over 30 type III CRISPR/Cas systems, where they likely function as accessory nucleases activated by cyclic oligoadenylate second messengers synthesized by these systems' effector complexes.

Keywords: CD-NTase; Endonuclease; abortive infection; bacteriophage immunity; second messenger signaling.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Allosteric Regulation
Bacterial Proteins / chemistry*
Bacterial Proteins / metabolism*
Bacteriophage lambda / genetics
Bacteriophage lambda / physiology
CRISPR-Cas Systems
DNA Cleavage
DNA Restriction Enzymes / chemistry
Deoxyribonuclease I / chemistry*
Deoxyribonuclease I / metabolism*
Escherichia coli / enzymology
Escherichia coli / immunology
Escherichia coli / virology*
Genome, Viral
Protein Multimerization
Second Messenger Systems

Substances

Bacterial Proteins
DNA Restriction Enzymes
Deoxyribonuclease I

Abstract

Publication types

MeSH terms

Substances

Grants and funding