Extended Data Fig. 5: Cryo-EM processing of NSUN2C271A-tRNALysTTT-SAH structures.
From: Substrate selectivity of the human RNA m5C methyltransferase NSUN2
a, Cryo-EM data processing workflow with a representative micrograph and 2D classes provided. Final map density is colored by domain (NTD: blue, MTD: purple, CTD1: light green, CTD2: dark green, RNA: orange, SAH: pink). b-g, Comparison of the “Conformation 1” (left) and “Conformation 2” (right) reconstructions. Unsharpened cryo-EM maps of protein-RNA complexes (top) or protein and RNA map segments (bottom) colored by local resolution (b), gold standard FSC curves with 0.5 and 0.143 thresholds (top) and conical FSC curves with relative distribution frequencies (bottom) (c), relative signal amounts by viewing direction in a 2D heatmap (top) and 3D projections (bottom) (d), molecular models for each reconstruction (e), and Q-scores calculated per protein (f) and RNA (g) residue. For models, protein is shown in cartoon representation and colored by domain, with RNA as orange ribbons and the SAH cofactor as pink sticks. Sigma (σ) denotes the threshold level in standard deviations from the mean. h-i, Secondary structure diagrams of the Acceptor- T-arm junction in tRNALysCTT (h), tRNALysTTT (i) conformations when complexed with NSUN2. Target cytosines are highlighted in yellow. j, Proposed secondary structure diagram of the Acceptor- T-arm junction in tRNALysTTT(A50C) when complexed with NSUN2. Target cytosines are highlighted in yellow.
