CRISPR-Cas9: Difference between revisions

<scene name='74/742625/Cv/26'>Each 5-bp segment of the hybrid is situated between the palm of one Cas7 subunit (e.g. Cas7.4) and the fingers of the adjacent subunit (e.g. Cas7.5)</scene>. 5-bp segment is colored red. Extensive contacts between the guide region of the crRNA and the Cas7 filament bury a large portion of the crRNA backbone, leaving the bases solvent-exposed. The absence of direct contacts between protein side chains and bases of the crRNA explains the lack of sequence specificity by Cascade for the guide sequence. <scene name='74/742625/Cv/27'>Close-up view of the bound crRNA</scene>. The DNA target has been removed for clarity. Intercalation by Met166 from Cas7 is highlighted. <scene name='74/742625/Cv/28'>Several highly conserved polar and positively charged residues (Arg20, Lys27, Ser40, Gln42, Lys45, and Lys49 - colored in magenta) from the palm of one Cas7 (e.g. Cas7.4) contact the RNA backbone</scene>, while the <scene name='74/742625/Cv/29'>fingers from the adjacent Cas7 (e.g. Cas7.5) subunit (residues 109-111, 163-169, colored in plum) contact both strands of the hybrid across the minor groove</scene>. Of note. the <scene name='74/742625/Cv/30'>Thumb (colored in olive) of one Cas7 subunit (e.g. Cas7.4) pushes through the guide-target hybrid at the 1-bp gaps</scene>. <scene name='74/742625/Cv/32'>Representation of 5 thumbs protruding guide-target hybrid at the 1-bp gaps</scene>.