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Figure 3.
Fig. 3. AN2690 forms an adduct with the terminal adenosine
(A76) of tRNA^Leu in the editing active site of LeuRS. (A)
Overall structure of the complex of T. thermophilus LeuRS with
tRNA^Leu and AN2690, showing the adenosine-AN2690 adduct
(ball-and-stick model, ringed in red) in the editing site and
leucine (space-filling model) in the synthetic site. The editing
domain is cyan; the catalytic domain, yellow; Zn-1 domain,
purple; the leucyl-specific insertion domain, black; the
anticodon-binding domain, red; the C-terminal domain, gold; zinc
atoms, gray spheres; and tRNA, blue tube. (B) Unbiased
difference map (1.85 Å resolution) for the AMP-AN2690
adduct in the editing site. (C) Diagram showing water molecules
(dark blue spheres) and hydrogen bonds (green dotted lines)
between editing site residues of LeuRS and the AMP-AN2690 adduct
(orange). Amino acid residues that are mutated in the S.
cerevisiae AN2690-resistant mutants are labeled and colored in
purple (table S2). The atoms are colored accordingly: boron,
mauve; fluorine, green; oxygen, red; nitrogen, light blue;
carbon, yellow; and phosphate, purple. (D) Superposition of
bound posttransfer editing substrate analog (Nva2AA, brown) (9)
and the AMP-AN2690 adduct (orange) obtained after superposing
the C  positions of the
editing domain of each complex.
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