Fig. 7

Structural effects of the K21W and T30R_S33E SIP mutations. The WT backbone and side chains are shown in light and dark grey, respectively, whereas the mutated residues are shown in red. The K21W mutation introduces additional stacking interaction between the Trp residues (> 85% of the MD simulation time) (a), whereas in the T30R_S33E variant a salt bridge between mutated residue R30 and WT residue E34 was detected (> 90% of the MD simulation time) (b). The role of the mutated E33 residue could not be elucidated from the MD simulations but, according to Rosetta calculations, it may positively influence the dimer stability. Images were rendered from the minimized average structures calculated from frames sampled in the last 100 ns of MD simulations. Analysis of the interactions of mutant residues in MD simulations was performed with the MD-RIP program