Fig. 1: Cryo-EM structure of human NSUN2–tRNA reaction intermediate.
From: Substrate selectivity of the human RNA m5C methyltransferase NSUN2
a, In vitro methylation activity of full-length wild-type (WT) human NSUN2 with indicated tRNA substrates, shown as mean ± standard deviation (s.d.) (n = 3). Statistical significance is indicated (two-tailed unpaired t-test). DPM, disintegrations per minute. b, In vitro crosslinking activity of NSUN2C271A with indicated tRNA substrates. Representative SDS–PAGE gel from three replicates is shown. For gel source data, see Supplementary Fig. 1. c, Domain organization of human NSUN2. d, Sharpened cryo-EM density map of the NSUN2C271A–tRNALysCTT complex with bound SAH (pink) and RNA (orange) in the D-arm conformation. The NSUN2 portion is coloured by domain as marked in c. e, Cloverleaf diagram of tRNALysCTT used in cryo-EM. Protein–RNA contacts (distance <3.8 Å) are coloured by the interacting protein domain, as in c, with the target cytosine highlighted in yellow. Unresolved nucleotide 76 is shown in grey. f–h, Models of the NSUN2C271A–tRNALysCTT–SAH complex in the D-arm conformation in cartoon representation from three different views, with SAH as pink sticks and m5Cyt48 as cyan sticks.
