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| Type |
Symposium |
| Area |
Recent Trends in Genome Editing Technique |
| Room No. |
Room 314 |
| Time |
FRI 10:40-: |
| Code |
LIFE2-5 |
| Subject |
Structures and interactions of anti-CRISPR proteins |
| Authors |
Euiyoung Bae
Department of Agricultural Biotechnology, Seoul National University, Korea |
| Abstract |
Clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) proteins provide bacterial adaptive immunity against bacteriophage infection. To counteract this defense mechanism, bacteriophages evolved anti-CRISPR (Acr) proteins that inactivate the antiphage CRISPR-Cas systems. Here, we report the crystal structures of two Acr proteins, AcrF2 and AcrIIA1. AcrF2 inhibits the type I-F CRISPR-Cas system in Pseudomonas aeruginosa. In this type, multiple Cas proteins (Csy1–4) comprise a surveillance complex (Csy complex) with CRISPR RNA (crRNA) for target recognition. AcrF2 binds to the Csy1-Csy2 heterodimers with nanomolar affinity. In the crystal structure of AcrF2, the arrangement of carboxyl side chains resembles the negative charge distribution of the dsDNA backbone, confirming that AcrF2 is a double-stranded DNA mimic blocking target recognition. AcrIIA1, encoded by Listeria monocytogenes prophages, is the most prevalent among the Acr proteins targeting type II-A CRISPR-Cas systems. AcrIIA1 forms a dimer with a novel two helical-domain architecture. The N-terminal domain of AcrIIA1 exhibits a helix-turn-helix motif similar to transcriptional factors. When overexpressed in Escherichia coli, AcrIIA1 associates with RNAs, suggesting that AcrIIA1 functions via nucleic acid recognition. Taken together, the structural and functional features of AcrF2 and AcrIIA1 suggest their distinct modes of Acr activity, expanding the diversity of the inhibitory mechanisms employed by Acr proteins. |
| E-mail |
bae@snu.ac.kr |
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122nd General Meeting of the KCS