title: Type V CRISPR-Cas Cpf1 endonuclease employs a unique mechanism for crRNA-mediated target DNA recognition.
abstract: CRISPR-Cas9 and CRISPR-Cpf1 systems have been successfully harnessed for genome editing. In the CRISPR-Cas9 system, the preordered A-form RNA seed sequence and preformed protein PAM-interacting cleft are essential for Cas9 to form a DNA recognition-competent structure. Whether the CRISPR-Cpf1 system employs a similar mechanism for target DNA recognition remains unclear. Here, we have determined the crystal structure of Acidaminococcus sp. Cpf1 (AsCpf1) in complex with crRNA and target DNA. Structural comparison between the AsCpf1-crRNA-DNA ternary complex and the recently reported Lachnospiraceae bacterium Cpf1 (LbCpf1)-crRNA binary complex identifies a unique mechanism employed by Cpf1 for target recognition. The seed sequence required for initial DNA interrogation is disordered in the Cpf1-cRNA binary complex, but becomes ordered upon ternary complex formation. Further, the PAM interacting cleft of Cpf1 undergoes an "open-to-closed" conformational change upon target DNA binding, which in turn induces structural changes within Cpf1 to accommodate the ordered A-form seed RNA segment. This unique mechanism of target recognition by Cpf1 is distinct from that reported previously for Cas9.
authors.affiliation: Key Laboratory of Infection and Immunity, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.|Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Pu
authors.initials: P
authors.lastname: Gao
authors.affiliation: Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.|NE-CAT, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60349, USA.
authors.forename: Kanagalaghatta R
authors.initials: KR
authors.lastname: Rajashankar
authors.affiliation: School of Life Science and Technology, Harbin Institute of Technology, Harbin 150880, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Dinshaw J
authors.initials: DJ
authors.lastname: Patel
mesh_terms: D020816:Amino Acid Motifs; D001483:Base Sequence; D064113:CRISPR-Cas Systems / Q000235:genetics*; D020134:Catalytic Domain; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D043224:Deoxyribonuclease (Pyrimidine Dimer) / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D012313:RNA; D004247:DNA; D043224:Deoxyribonuclease (Pyrimidine Dimer)