01990nam a2200265Ia 4500003001000000005001700010040000900027245008000036490004600116520116500162650001201327650002401339650000901363650001501372650001501387650001701402650001901419650000901438650002401447650002701471700001301498700001601511856015601527008004101683MX-MdCICY20260521091532.0  cCICY10aInhibition Mechanism of an Anti-CRISPR Suppressor AcrIIA4 Targeting SpyCas90 vMolecular Cell, 67(1), p.117-127.e5, 20173 aProkaryotic CRISPR-Cas adaptive immune systems utilize sequence-specific RNA-guided endonucleases to defend against infection by viruses, bacteriophages, and mobile elements, while these foreign genetic elements evolve diverse anti-CRISPR proteins to overcome the CRISPR-Cas-mediated defense of the host. Recently, AcrIIA2 and AcrIIA4, encoded by Listeria monocytogene prophages, were shown to block the endonuclease activity of type II-A Streptococcus pyogene Cas9 (SpyCas9). We now report the crystal structure of AcrIIA4 in complex with single-guide RNA-bound SpyCas9, thereby establishing that AcrIIA4 preferentially targets critical residues essential for PAM duplex recognition, as well as blocks target DNA access to key catalytic residues lining the RuvC pocket. These structural insights, validated by biochemical assays on key mutants, demonstrate that AcrIIA4 competitively occupies both PAM-interacting and non-target DNA strand cleavage catalytic pockets. Our studies provide insights into anti-CRISPR-mediated suppression mechanisms for inactivating SpyCas9, thereby broadening the applicability of CRISPR-Cas regulatory tools for genome editing.14aACRIIA414aANTI-CRISPR PROTEIN14aCAS914aCRISPR RNA14aCRISPR-CAS14aENDONUCLEASE14aGENOME EDITING14aRUVC14aTARGET DNA CLEAVAGE14aTRANS-ACTIVATING CRRNA12aYang, H.12aPatel, D.J.40uhttps://drive.google.com/file/d/1fsUqfX3fWNfkbOGceFMhah5WPA9fQkr3/view?usp=drivesdkzPara ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx250602s9999    xx |||||s2   |||| ||und|d