Fig. 5: Model for the DNA target strand traversal toward the RuvC catalytic core in CRISPR-Cas12a.
From: An alpha-helical lid guides the target DNA toward catalysis in CRISPR-Cas12a
a Upon cleavage of the DNA non-target strand (NTS), the α-helical lid assumes an open conformation, exposing the RuvC catalytic core, while the DNA target strand (TS) locates close to the REC2 domain12. b The α-helical lid, in its open conformation, anchors the crRNA:TS duplex by establishing electrostatic interactions. c The inward bending of the REC2 and Nuc domains pushes the crRNA:TS duplex, while aiding the bending of the DNA TS and facilitating its conformational transition. d The α-helical lid binds the DNA TS and guides it toward the RuvC catalytic core. The closure of Nuc aids the TS to accommodate within RuvC for cleavage.
