FIGURE 4.

Structural conformations of the salt bridge interactions in the de novo TIM barrels. (a) sTIM11noCys‐SB (crystal form 1, PDB ID: 7OSU). (b) DeNovoTIM6‐SB (crystal form 1, PDB ID: 7OSV). (c) DeNovoTIM13‐SB (PDB ID: 7P12). In all panels, upper figures indicate the view from the bottom of the barrel with the salt bridge residues highlighted in sticks. 2Fo–Fc electron density maps contoured at 1σ are shown as a gray mesh for all the residues/water involved in the salt bridge cluster. Lower figures show the side view of the salt bridge interactions to analyze their planarity. Dotted lines indicate the salt bridge interactions between the mutated residues whose measures are reported in Table 2