1
|
Kim DY, Han JH, Lee SY, Ha HJ, Park HH. Novel structure of the anti-CRISPR protein AcrIE3 and its implication on the CRISPR-Cas inhibition. Biochem Biophys Res Commun 2024; 722:150164. [PMID: 38797150 DOI: 10.1016/j.bbrc.2024.150164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Revised: 05/14/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
As a response to viral infections, bacteria have evolved the CRISPR-Cas system as an adaptive immune mechanism, enabling them to target and eliminate viral genetic material introduced during infection. However, viruses have also evolved mechanisms to counteract this bacterial defense, including anti-CRISPR proteins, which can inactivate the CRISPR-Cas adaptive immune system, thus aiding the viruses in their survival and replication within bacterial hosts. In this study, we establish the high-resolution crystal structure of the Type IE anti-CRISPR protein, AcrIE3. Our structural examination showed that AcrIE3 adopts a helical bundle fold comprising four α-helices, with a notably extended loop at the N-terminus. Additionally, surface analysis of AcrIE3 revealed the presence of three acidic regions, which potentially play a crucial role in the inhibitory function of this protein. The structural information we have elucidated for AcrIE3 will provide crucial insights into fully understanding its inhibitory mechanism. Furthermore, this information is anticipated to be important for the application of the AcrIE family in genetic editing, paving the way for advancements in gene editing technologies.
Collapse
Affiliation(s)
- Do Yeon Kim
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Ju Hee Han
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea
| | - So Yeon Lee
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Hyun Ji Ha
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul, 06974, Republic of Korea; Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul, 06974, Republic of Korea.
| |
Collapse
|
2
|
Yin P, Zhang Y, Yang L, Feng Y. Non-canonical inhibition strategies and structural basis of anti-CRISPR proteins targeting type I CRISPR-Cas systems. J Mol Biol 2023; 435:167996. [PMID: 36754343 DOI: 10.1016/j.jmb.2023.167996] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/10/2023] [Accepted: 01/30/2023] [Indexed: 02/08/2023]
Abstract
Mobile genetic elements (MGEs) such as bacteriophages and their host prokaryotes are trapped in an eternal battle against each other. To cope with foreign infection, bacteria and archaea have evolved multiple immune strategies, out of which CRISPR-Cas system is up to now the only discovered adaptive system in prokaryotes. Despite the fact that CRISPR-Cas system provides powerful and delicate protection against MGEs, MGEs have also evolved anti-CRISPR proteins (Acrs) to counteract the CRISPR-Cas immune defenses. To date, 46 families of Acrs targeting type I CRISPR-Cas system have been characterized, out of which structure information of 21 families have provided insights on their inhibition strategies. Here, we review the non-canonical inhibition strategies adopted by Acrs targeting type I CRISPR-Cas systems based on their structure information by incorporating the most recent advances in this field, and discuss our current understanding and future perspectives. The delicate interplay between type I CRISPR-Cas systems and their Acrs provides us with important insights into the ongoing fierce arms race between prokaryotic hosts and their predators.
Collapse
Affiliation(s)
- Peipei Yin
- Jiangxi Provincial Key Laboratory of Natural Active Pharmaceutical Constituents, College of Chemical and Biological Engineering, Yichun University, Yichun 336000, China
| | - Yi Zhang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lingguang Yang
- Jiangxi Provincial Key Laboratory of Natural Active Pharmaceutical Constituents, College of Chemical and Biological Engineering, Yichun University, Yichun 336000, China
| | - Yue Feng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
| |
Collapse
|
3
|
Lee SY, Birkholz N, Fineran PC, Park HH. Molecular basis of anti-CRISPR operon repression by Aca10. Nucleic Acids Res 2022; 50:8919-8928. [PMID: 35920325 PMCID: PMC9410881 DOI: 10.1093/nar/gkac656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/05/2022] [Accepted: 07/21/2022] [Indexed: 01/11/2023] Open
Abstract
CRISPR-Cas systems are bacterial defense systems for fighting against invaders such as bacteriophages and mobile genetic elements. To escape destruction by these bacterial immune systems, phages have co-evolved multiple anti-CRISPR (Acr) proteins, which inhibit CRISPR-Cas function. Many acr genes form an operon with genes encoding transcriptional regulators, called anti-CRISPR-associated (Aca) proteins. Aca10 is the most recently discovered Aca family that is encoded within an operon containing acrIC7 and acrIC6 in Pseudomonas citronellolis. Here, we report the high-resolution crystal structure of an Aca10 protein to unveil the molecular basis of transcriptional repressor role of Aca10 in the acrIC7-acrIC6-aca10 operon. We identified that Aca10 forms a dimer in solution, which is critical for binding specific DNA. We also showed that Aca10 directly recognizes a 21 bp palindromic sequence in the promoter of the acr operon. Finally, we revealed that R44 of Aca10 is a critical residue involved in the DNA binding, which likely results in a high degree of DNA bending.
Collapse
Affiliation(s)
- So Yeon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.,Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| | - Nils Birkholz
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.,Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| |
Collapse
|
4
|
Kang YJ, Park HH. High-resolution crystal structure of the anti-CRISPR protein AcrIC5. Biochem Biophys Res Commun 2022; 625:102-108. [DOI: 10.1016/j.bbrc.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022]
|
5
|
Lee SY, Kim GE, Park HH. Molecular basis of transcriptional repression of anti-CRISPR by anti-CRISPR-associated 2. Acta Crystallogr D Struct Biol 2022; 78:59-68. [PMID: 34981762 DOI: 10.1107/s2059798321011670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 11/04/2021] [Indexed: 11/10/2022] Open
Abstract
CRISPR-Cas systems are well known host defense mechanisms that are conserved in bacteria and archaea. To counteract CRISPR-Cas systems, phages and viruses have evolved to possess multiple anti-CRISPR (Acr) proteins that can inhibit the host CRISPR-Cas system via different strategies. The expression of acr genes is controlled by anti-CRISPR-associated (Aca) proteins that bind to an upstream promoter and regulate the expression of acr genes during transcription. Although the role of Aca as a transcriptional repressor has been demonstrated, the mechanism of action of Aca has not been determined. Here, the molecular mechanism underlying the Aca2-mediated transcriptional control of acr genes was elucidated by determining the crystal structure of Aca2 from Oceanimonas smirnovii at a high resolution of 1.92 Å. Aca2 forms a dimer in solution, and dimerization of Aca2 is critical for specific promoter binding. The promoter-binding strategy of dimeric Aca2 was also revealed by performing mutagenesis studies. The atomic structure of the Aca family shown in this study provides insights into the fine regulation of host defense and immune-escape mechanisms and also demonstrates the conserved working mechanism of the Aca family.
Collapse
Affiliation(s)
- So Yeon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Gi Eob Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| |
Collapse
|
6
|
Mejdani M, Pawluk A, Maxwell KL, Davidson AR. Anti-CRISPR AcrIE2 Binds the Type I-E CRISPR-Cas Complex But Does Not Block DNA Binding. J Mol Biol 2020; 433:166759. [PMID: 33338493 DOI: 10.1016/j.jmb.2020.166759] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/02/2020] [Accepted: 12/09/2020] [Indexed: 02/06/2023]
Abstract
Anti-CRISPRs are protein inhibitors of CRISPR-Cas systems. They are produced by phages and other mobile genetic elements to evade CRISPR-Cas-mediated destruction. Anti-CRISPRs are remarkably diverse in sequence, structure, and functional mechanism; thus, structural and mechanistic investigations of anti-CRISPRs continue to yield exciting new insights. In this study, we used nuclear magnetic resonance (NMR) spectroscopy to determine the solution structure of AcrIE2, an anti-CRISPR that inhibits the type I-E CRISPR-Cas system of Pseudomonas aeruginosa. Guided by the structure, we used site-directed mutagenesis to identify key residues that are required for AcrIE2 function. Using affinity purification experiments, we found that AcrIE2 binds the type I-E CRISPR-Cas complex (Cascade). In vivo transcriptional assays, in which Cascade was targeted to promoter regions, demonstrated that Cascade still binds to DNA in the presence of AcrIE2. This is the first instance of a type I anti-CRISPR that binds to a CRISPR-Cas complex but does not prevent DNA-binding. Another unusual property of AcrIE2 is that the effect of Cascade:AcrIE2 complex binding to promoter regions varied depending on the position of the binding site. Most surprisingly, Cascade:AcrIE2 binding led to transcriptional activation in some cases rather than repression, which did not occur when Cascade alone bound to the same sites. We conclude that AcrIE2 operates through a distinct mechanism compared to other type I anti-CRISPRs. While AcrIE2 does not prevent Cascade from binding DNA, it likely blocks subsequent recruitment of the Cas3 nuclease to Cascade thereby preventing DNA cleavage.
Collapse
Affiliation(s)
- Marios Mejdani
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - April Pawluk
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Karen L Maxwell
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
| | - Alan R Davidson
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|