Figure 5.

Common reagents bound in the active sites of proteins. The protein structures are shown in cartoon representation and colored green or gray. The bound ligands are drawn as sticks and are colored yellow (carbon), red (oxygen) and blue (nitrogen). The interacting residues are also drawn as sticks with their C atoms colored cyan. (a) An SO₄ ²⁻ ion bound in the active site of protein YP_001181608.1 (PDB code 3gxg). (b) A citrate molecule bound to YP_001089791.1 (PDB code 3g68) helped to identify the potential active site and was supported by substrates (gray) bound to the same location in structurally similar proteins (gray; PDB codes 1mos, 2bpl, 2poc and 2v4m). (c) A Tris molecule bound in the active site of YP_001304206.1 (PDB code 3h3l).