手法: Torsion angle dynamics (Dyana 1.5), simulated annealing (X-Plor 3.851) ソフトェア番号: 1 詳細: Hydrogen bond restraints were assigned based on protection from solvent exchange, and consistency of hydrogen bonds with preliminary structures. Backbone phi and psi dihedral restraints were ...詳細: Hydrogen bond restraints were assigned based on protection from solvent exchange, and consistency of hydrogen bonds with preliminary structures. Backbone phi and psi dihedral restraints were obtained from 1Ha, 13Ca, 13Cb, 13C and 15N chemical shifts using the program TALOS (Cornilescu et al., 1993). Side-chain chi1 restraints were from 3D HNHB data, in conjunction with HN-HBETA 2/HN-HBETA 3 and HALPHA-HBETA 2/HALPHA-HBETA 3 NOE intensity ratios. These data were also used to obtain stereospecific assignments for the C-BETA protons of 37 residues. NOEs involving the remainder of prochiral groups with non-degenerate chemical shifts were treated as ambiguous with respect to stereospecific assignments, and represented as 1/^-1/6 sums using XPLOR 3.851 (Brunger, 1992). Initial structures calculated with this approach, were used to identify sites in which one of the stereospecific assignments was more consistent with the remaining distance and dihedral restraints. This enabled stereospecific assignment of a further 13 methylene groups, and 13 valine and leucine prochiral methyl groups. For the final NMR calculations, 400 random conformations were subjected to restrained torsion angle dynamics with the program Dyana 1.5 (Guentert et al., 1997). The 40 structures with the smallest Dyana target functions were refined with a published simulated annealing protocol (Nilges et al., 1991), using the program XPLOR 3.851 (Brunger, 1992). The 15 lowest-energy simulated annealing structures with no distance or dihedral violations larger than 4 were kept for analysis.
代表構造
選択基準: closest to the average
NMRアンサンブル
コンフォーマー選択の基準: structures with the lowest energy 計算したコンフォーマーの数: 400 / 登録したコンフォーマーの数: 15