A Type I-F Anti-CRISPR Protein Inhibits the CRISPR-Cas Surveillance Complex by ADP-Ribosylation

• DOI: 10.1016/j.molcel.2020.09.015
• Publication Date: 2020-10-12T14:44:31Z
• Authors: Yiying Niu; Lingguang Yang; Teng Gao; Changpeng Dong; Buyu Zhang; Peipei Yin; Ann-Katrin Hopp; Dongdong Li; Rui Gan; Hongou Wang; Xi Liu; Xueli Cao; Yongchao Xie; Xianbin Meng; Haiteng Deng; Xiaohui Zhang; Jie Ren; Michael O. Hottiger; Zeliang Chen; Yi Zhang; Xiaoyun Liu; Yue Feng
• Keywords: Models, Molecular; 0301 basic medicine; CRISPR-Associated Proteins; Cryoelectron Microscopy; DNA; 10226 Department of Molecular Mechanisms of Disease; 1307 Cell Biology; RNA, Bacterial; Viral Proteins; 03 medical and health sciences; ADP-Ribosylation; Bacterial Proteins; 1312 Molecular Biology; 570 Life sciences; biology; Bacteriophages; Clustered Regularly Interspaced Short Palindromic Repeats; CRISPR-Cas Systems

CRISPR-Cas systems are bacterial anti-viral systems, and phages use anti-CRISPR proteins (Acrs) to inactivate these systems. Here, we report a novel mechanism by which AcrIF11 inhibits the type I-F CRISPR system. Our structural and biochemical studies demonstrate that AcrIF11 functions as a novel mono-ADP-ribosyltransferase (mART) to modify N250 of the Cas8f subunit, a residue required for recognition of the protospacer-adjacent motif, within the crRNA-guided surveillance (Csy) complex from Pseudomonas aeruginosa. The AcrIF11-mediated ADP-ribosylation of the Csy complex results in complete loss of its double-stranded DNA (dsDNA) binding activity. Biochemical studies show that AcrIF11 requires, besides Cas8f, the Cas7.6f subunit for binding to and modifying the Csy complex. Our study not only reveals an unprecedented mechanism of type I CRISPR-Cas inhibition and the evolutionary arms race between phages and bacteria but also suggests an approach for designing highly potent regulatory tools in the future applications of type I CRISPR-Cas systems.