FIGURE 2.

Homology-based model of the structure of the catalytic domain. (A) An homology-based model for the catalytic region of Arabidopsis RNase E based on the E. coli X-ray crystal structure (see Materials and Methods). In order to build the model, the plant-specific S1 domain insertion was removed and residues Pro₄₀₇ and Lys₅₃₀ were joined together. The region of the RNase H and the S1 domains is shown as blue ribbon. The region following the plant-specific domain toward the carboxy terminus is shown as white ribbon. Residues Pro₄₀₇ and Lys₅₃₀, located before and after the plant-specific domain, are shown as green bars. Residues Lys₅₄₆ and Lys₅₅₂ (corresponding to the Lys₁₀₆ and Lys₁₁₂ of E. coli) are shown as red bars. The small domain of the catalytic part is not presented in this panel. (B) The modeled catalytic region of Arabidopsis RNase E (white) superimposed on the E. coli crystal structure from PDB 2bx2, chain L (pink).