Figure 3 - full size

Figure 3.
Figure 3 (A) General view of the dimeric aspartyl-tRNA synthetase from E.coli complexed with yeast tRNA^Asp and aspartyl-adenylate. The tRNA^Asp molecules, colored in red and yellow, are bound to one protein subunit shown in brown and white, respectively. (B) AspRS surface buried by the tRNA in monomer 1 (left) and monomer 2 (right) calculated and displayed using GRASP (Nicholls and Honig, 1991). The surface is colored according to a distance array between the two molecular surfaces: distances <2.5 Å between the tRNA and the enzyme are drawn in green, and distances between 2.5 and 3.5 Å are in yellow. The interaction surfaces are highly similar for the protein N-terminal domain in both monomers but vary through the rest of the complex. (C) Ribbon representation of one AspRS subunit in gray (monomer 1) of the heterologous complex with the bound yeast tRNA^Asp in yellow. The E.coli tRNA^Asp as seen in the cognate complex is drawn in blue after superposition of the enzymes on their active sites. (D) Relative position of the two tRNAs of the heterologous complex. Superposition was optimized on the two subunit active sites. The tRNA^Asp from monomer 1 is drawn in yellow, the tRNA from monomer 2 in red. (E) Comparison of the tRNA molecule from monomer 2 of the heterologous complex (red) and the free (uncomplexed) yeast tRNA^Asp (green) (Moras et al., 1980). Figures 3, Figures 4, 5 were generated using the Program SETOR (Evans, 1998).