Figure 2.

Ribbon diagram of the structure of Thermus thermophilus IleRS [coordinates are from Nureki et al. (21)]. The CP1 domain is depicted in tan. (A) Sites of mutations from previous editing studies (12, 21, 29, 37, 38). Red residues symbolize mutations that had significant effects on editing, violet residues represent mutations that resulted in an alteration in the specificity of the editing reaction, and yellow side chains are those that, when mutated, resulted in a WT phenotype for editing. (B) Proposed mutation sites (shown in orange) in the IleRS hinge region. The numbering of residues is based on that of the E. coli enzyme.