FIGURE 3.

Sequence and structure of CalE7. A, sequence alignment of CalE7 with SgcE10 and the hypothetical protein (AQ1494) from A. aeolicus (PDB code 2EGI). Strictly conserved residues are highlighted in red, and partially conserved residues are yellow. The residues mutated in the present study are indicated by blue asterisks. B, representation of the CalE7 monomer. The protein secondary structures elements are labeled and colored from blue at the N terminus to red at the C terminus. C, schematic representation of the CalE7 tetramer showing the Jeffamine fragment (sticks) binding site between two subunits. Subunits are colored gray and cyan for one dimer and dark blue and dark gray for the other. The β5–α3 loops at the active sites is colored red. The inset shows a close-up view of the Jeffamine binding site superposed with 4-hydroxybenzoyl-CoA-bound 4-BHT (PDB code: 1LO9). D, simulated annealing difference Fourier map with coefficients |F_obs| − |F_calc| and phases calculated from the protein model with atoms from the Jeffamine fragment omitted and contoured at a level of 3σ.