Supplementary Figure 1: Anomalous scattering within the asymmetric unit of LbaCa13a, RNA content of crystals, and crRNA electron density maps.
From: Guide-bound structures of an RNA-targeting A-cleaving CRISPR–Cas13a enzyme
a, Opposing perspectives of LbaCas13a are shown as a transparent cartoon with domains colored as in Fig. 1c. The anomalously scattering iodides, sulfurs, and phosphates are shown as yellow, orange, and blue colored spheres, respectively. The anomalous Fourier difference map shown is contoured to 3σ. b, Urea-PAGE gel of 20-nt and 24-nt spacer-containing pre-crRNA substrates incubated with LbaCas13a to produce the complex prepared for crystallization. Crystals of each complex were looped, washed, and dissolved to determine the presence of full-length mature crRNA after crystallization. c, Simulated annealing mFo-DFc omit electron density map of the entire crRNA over two orthogonal views contoured to 2σ. d, The discontinuous crRNA contained within the asymmetric unit (two copies denoted as 1 and 2) of the 20-nt spacer-containing structure of LbaCas13a. Simulated annealing mFo-DFc omit electron density map of the entire crRNA contoured to 3σ. e, The discontinuous crRNA contained within the 28-nt spacer containing structure of LshCas13a (Liu et al., Cell, 168, 121-134, 2017). Simulated annealing mFo-DFc omit electron density map of the entire crRNA contoured to 3σ.
