Fig. 2.

Structure of the dimeric human TrpRS with one monomer shown in color. The circled CP1 insertion of the Rossmann fold domain forms the dimerization interface. All three domains [N-terminal appended domain (blue), Rossmann fold catalytic domain (yellow), and anticodon recognition domain (green)] were resolved in one monomer of the dimer with a disordered linker of 21 residues connecting the N-domain and the Rossmann fold domain. However, in the other monomer, the first 96 residues, which include the N-terminal domain, the linker region, and part of the Rossmann fold catalytic domain, were completely disordered. A bound Trp-AMP was found only in the monomer with the resolved N-domain.