Crystal structures of the class Ia aaRS•tRNA complexes. The domains of the class Ia aaRS are colored as follows: Rossmann-fold (aminoacylation) domain, green; CP core, white; CP1 (editing) domain, cyan; CP2 domain, orange; CP3 domain, yellow; SC-fold domain, red; α-helix bundle domain, violet; anticodon-stem-binding domain, aquamarine; coiled-coil domain (ValRS), lime green; wobble-base-binding domain (IleRS), dark orange; N20-binding domain (ArgRS), dark orange; helical insertion (ArgRS), slate blue. Molecules bound to the Rossmann-fold domains are shown as ball-and-stick representations. Transfer RNAs are blue tubes. The first, second, and third anticodon nucleotides are shown as green, cyan, and yellow sticks, respectively. Ψ20 of the tRNAArg is shown as pink sticks. Zinc ions are shown as red balls.
