Cas5d processes pre-crRNA and is a member of a larger family of CRISPR RNA endonucleases

Homology modeling of Cas5d as a member of the larger pre-crRNA RNA endonuclease family. (A) X-ray structures of (top) Cse3 (PDB 3QRQ) and (bottom) MS0988 (PDB 3KG4). (B) Overlay of the X-ray structures of MS0988 (yellow) and Cse3 (orange) as determined by iSuperpose (Neron et al. 2009). (C) Overlay of the X-ray structure of MS0988 (yellow) with that of a Cse3•RNA complex (PDB 3QRQ). Cse3 and RNA are depicted in yellow and cyan, respectively. (D) Surface electrostatics for Cse3 and MS0988 within the actual and modeled protein RNA complexes. (Blue) Basic; (red) acidic; (white) neutral.