Fig. 4.

Rosetta homology modeling of mTSPO improves model energy over available structural templates. A Rosetta energy vs. Cα-RMSD plot for energy-minimized mTSPO^NMR-opt and mTSPO^RosettaCM models created with different sampling strategies. The RMSD was calculated relative to the final lowest-energy mTSPO^RosettaCM model after one round of RosettaCM and three rounds of energy minimization with FastRelax (Conway et al. 2014). The colors refer to the following sampling strategies: optimization of mTSPO^NMR with Rosetta FastRelax (yellow), RosettaCM based on bcTSPO^X-Ray (orange), RosettaCM based on rsTSPO^X-Ray (green), RosettaCM based on bcTSPO^X-ray, rsTSPO^X-ray and mTSPO^NMR (gray); additional energy minimization of single and multiple template mTSPO^RosettaCM models with FastRelax (red), three rounds of FastRelax on multiple template mTSPO^RosettaCM models (blue). B Box plot of the Rosetta energy of the top 20 models produced by each sampling strategy. The color scheme follows that of panel A. The relaxed mTSPO^RosettaCM model has improved energy over other Rosetta models. c Cartoon representation of experimental TSPO structures and the mTSPO^RosettaCM model. The flexible tail region (mTSPO residues 160–169, rsTSPO residues 151–157) is omitted for clarity. The N- and C-terminus and TM helix regions are labeled. The Cα-RMSD of mTSPO^RosettaCM relative to the experimental templates was calculated after sequence-independent structural alignment with DALI (Holm and Rosenström 2010): 4.1Å (mTSPO^NMR), 3.3Å (bcTSPO^X-Ray) and 3.5Å (rsTSPO^X-Ray)