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. Author manuscript; available in PMC: 2020 Jan 10.
Published in final edited form as: Cell. 2018 Nov 29;176(1-2):239–253.e16. doi: 10.1016/j.cell.2018.10.052

Figure 2. Cryo-EM Structure of the Csm-NTR Complex.

Figure 2.

(A) Schematic representation of the crRNA-NTR duplex. The base pairs observed in the NTR-bound Csm complex are depicted by lines. The non-cognate target RNA is shown in blue. The ordered and disordered nucleotides of NTR are shown in white and black, respectively.

(B) Overall structure of the NTR-bound Csm complex.

(C) The β-thumb of each Csm3 subunit inserts into the crRNA-NTR duplex, leading to the periodical nucleotide displacement of both RNA strands.

(D) Structural comparison between Csm-crRNA binary complex and Csm-crRNA-NTR ternary complex showing the conformational change upon target RNA binding. Vector length correlates with the domain motion scale (color-coded as defined in Figure 1A).

(E) Nucleotides at positions (−2)′–(−5)′ in the 3′ anti-tag of NTR base pair with nucleotides (−2)–(−5) in the 5′ tag of the crRNA.

(F) The side-chain of Arg253 of Csm4 subunit inserts into the bases at position (−6) of crRNA and target RNA, preventing base pairing at this position.

See also Figures S2 and S3 and Table S2.