The final model of CsTegu20.6 was determined after the loops and both main- and side-chains of the initial model were further refined using GalaxyLoop  and GalaxyRefine , respectively (Figure 3). The ab initio modeling method, hybrid-type energy function and an efficient search method were employed within GalaxyLoop. Then, both the backbone and side chain of the structure were refined using GalaxyRefine based on repeated perturbation and, hence, overall conformational relaxation by short molecular dynamics simulations. Through the refinement procedure of the initial model, the stereochemical quality of the final model was markedly improved over that of the initial model, especially in terms of the ERRAT values from 48.5% (Figure S3D) to 80.8% (Figure 3D). ERRAT calculates the overall quality score of non-bonded atomic interactions compared with the database of reliable experimental structures.