(C) Detailed view of the 3D model of the predicted catalytic site of human TRMT5. TRMT5 residues corresponding to the catalytically important amino acids in aTrm5 are indicated in dark green. Seven out of nine catalytically important residues are absolutely conserved in TRMT5 and aTrm5, and the remaining two, His289 (Methanocaldococcus jannaschii Arg186) and Arg454 (Methanocaldococcus jannaschii Lys318), share very similar chemical properties between the two proteins. The residues mutated in individuals 73901 and 65205, Arg291 and Met389, respectively, are indicated in red.