FIG. 2.
Location of the type 1 metal binding sites. (A) The type 1 metal binding site is located at the interface of α3 and α4 from one monomer (magenta) and α1′ from the other monomer (green). Residues at the dimer interface are labeled. (B) The vicinity of the type 1 metal binding site. The 2Fo-Fc simulated annealing omit electron density map at the 1σ level is shown for residues 58 to 61 in helix α4 and residues 11 to 13 from the other monomer. A hydrogen bond is formed between the hydroxyl of Tyr-12 and the thiol of Cys-58. (C) Molecules 1, 2, and 4 of SeMet CadC structure can be traced up to Cys-7. The 2Fo-Fc simulated annealing omit electron density map at the 1σ level is shown for residues 7 to 10 of molecule 2. (D) The N termini of molecules 2 and 4 of the SeMet CadC structure are superimposed on molecule 1, showing that, without metal ions bound to the type 1 site, Cys-7 can assume multiple orientations. The side chains of Cys-7, Cys-58′, and Cys-60′ are shown.