Fig. 5: The structural superposition and possible CMP binding mode.
From: Crystal structure of human METTL6, the m3C methyltransferase
a structural superimposition of the backbone structure of hMETTL6 (PDB 7EZG, colored cyan) onto that of SAM-dependent methyltransferase cg3271 from Corynebacterium glutamicum (PDB 3H2B, green), SAM-dependent methyltransferases q8puk2_metma from Methanosarcina mazei (PDB 3SM3, magenta), methyl transferase from Methanosarcina acetivorans (PDB 6MRO, yellow), SAM-dependent methyltransferase (np_349143.1) from Clostridium acetobutylicum (PDB 2P8J, pink), and Burkholderia thailandensis 1,6- didemethyltoxoflavin-N1-methyltransferase bound by 1,6-didemethyltoxoflavin and SAH (PDB 5UFM, orange). The figure was shown in cross-eyed stereoview. b The docking model of hMETTL6-SAM-CMP ternary complex. Right: the close-up of the active center. The 4.9 Å distance between the methyl group carbon of SAH and N1 of CMP was indicated by the blue line. c The surface representation of the complex. d The methyltransferase activity assays of the two mutants S161A and T217A. The WT activity was normalized to 100%, while the activities of the mutants were shown as percentages of that of WT. Data are shown as mean ± SD. Each group was compared using un-paired t-test (n = 3; two-tailed P value; ***P < 0.0001).
