ジャーナル: J.Mol.Biol. / 年: 2001 タイトル: A double chain reversal loop and two diagonal loops define the architecture of a unimolecular DNA quadruplex containing a pair of stacked G(syn)-G(syn)-G(anti)-G(anti) tetrads flanked ...タイトル: A double chain reversal loop and two diagonal loops define the architecture of a unimolecular DNA quadruplex containing a pair of stacked G(syn)-G(syn)-G(anti)-G(anti) tetrads flanked by a G-(T-T) Triad and a T-T-T triple. 著者: Kuryavyi, V. / Majumdar, A. / Shallop, A. / Chernichenko, N. / Skripkin, E. / Jones, R. / Patel, D.J.
STRUCTURES WITH ACCEPTABLE COVALENT GEOMETRY, STRUCTURES WITH FAVORABLE NON-BOND ENERGY,STRUCTURES WITH THE LEAST RESTRAINT VIOLATIONS,BACK-CALCULATED DATA AGREE WITH EXPERIMENTAL NOESY SPECTRUM
Text: SITE-SPECIFIC SUBSTITUTED SAMPLES CONTAINING 8BR-A,8BR-G,DU,5BR-DU, 2,6A, I, 5ME-C ANALOGS AND SITE-SPECIFIC OR UNIFORMLY 13C AND 15N LABELED SAMPLES HAVE BEEN USED
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試料調製
詳細
Solution-ID
内容
溶媒系
1
5-10 MM DNA (SINGLE STRANDS); 5MM SODIUM PHOSPHATE BUFFER
90% H2O/10% D2O
2
5-10MM DNA (SINGLE STRANDS); 5MM SODIUM PHOSPHATE BUFFER
手法: DISTANCE GEOMETRY, SIMULATED ANNEALING, DISTANCE RESTRAINED MOLECULAR DYNAMICS REFINEMENT, RELAXATION MATRIX INTENSITY REFINEMENT ソフトェア番号: 1 詳細: A TOTAL OF 100 INITIAL DNA STRUCTURES WERE GENERATED USING THE METRIC MATRIX DISTANCE GEOMETRY PROTOCOL OF X-PLOR WITH THE DISTANCE RESTRAINTS OBTAINED EXPERIMENTALLY SPECIFIED AS NOE. ...詳細: A TOTAL OF 100 INITIAL DNA STRUCTURES WERE GENERATED USING THE METRIC MATRIX DISTANCE GEOMETRY PROTOCOL OF X-PLOR WITH THE DISTANCE RESTRAINTS OBTAINED EXPERIMENTALLY SPECIFIED AS NOE. FOURTEEN STRUCTURES WERE IDENTIFIED BASED ON THE CRITERION ACCEPTABLE COVALENT GEOMETRY, LOW DISTANCE RESTRAINT VIOLATIONS AND FAVORABLE NON-BONDED ENERGY. THE VARIATION IN ENERGIES WITHIN THIS SUBSET OF STRUCTURES WAS 46 KCAL/MOL AND WAS SEPARATED FROM THE REMAINING STRUCTURES BY A GAP OF 200 KCAL/MOL. THE TEN BEST STRUCTURES FROM THIS SUBSET OF FOURTEEN WERE FURTHER OPTIMIZED WITH RESTRAINED MOLECULAR DYNAMICS, MOLECULAR MECHANICS AND RELAXATION MATRIX INTENSITY REFINEMENT. THE PROTOCOLS ARE AS FOLLOWS. THE DYNAMICS WAS INITIATED AT 300K AND THE TEMPERATURE WAS INCREASED TO 1000K DURING 7PS. AFTER 0.5 PS THE FORCE CONSTANTS WERE GRADUALLY SCALED DURING 17.5 PSEC IN THE PROPORTION 1: 4: 8 FOR THREE CLASSES OF NOE: EXCHANGEABLE, NONEXCHANGEABLE AND HYDROGEN BONDS, RESP. THE STRUCTURES WERE THEN SLOWLY COOLED TO 300K IN 2.8 PS AND EQUILIBRATED AT 300K FOR 12 PS. SOFT PLANARITY RESTRAINTS WERE SWITCHED OFF BEFORE THE EQUILIBRATION STAGE.THE COORDINATES SAVED EVERY 0.5 PS DURING THE LAST 4.0 PS WERE AVERAGED AND THE AVERAGE STRUCTURE WAS SUBJECTED TO 3000 STEPS OF MINIMIZATION. THE DIHEDRAL ANGLE RESTRAINTS AND HYDROGEN BONDS OF THE GGGG TETRADS WERE MAINTAINED THROUGHOUT. THE OBTAINED STRUCTURES WERE SUBJECTED TO RELAXATION MATRIX INTENSITY REFINEMENT. THE INTENSITY VOLUMES WERE USED AS RESTRAINTS AND NON-EXCHANGEABLE PROTON DISTANCE RESTRAINTS WITH THE SCALE FACTOR OF 0.1 RELATIVE TO THE INTENSITY RESTRAINTS. SOFT PLANARITY RESTRAINTS MAINTAINED DURING RELAXATION REFINEMENTS WERE SWITCHED OFF BEFORE THE FINAL STEPS OF MINIMIZATION. THE RELAXATION PATHWAYS WERE CALCULATED USING CUTOFF 4.5 ANGSTROM AND 7.91 NS ISOTROPIC CORRELATION TIME. THE STRUCTURES EXHIBIT PAIRWISE R.M.S.D. VALUE OF 1.07 A.
代表構造
選択基準: closest to the average, fewest violations
NMRアンサンブル
コンフォーマー選択の基準: STRUCTURES WITH ACCEPTABLE COVALENT GEOMETRY, STRUCTURES WITH FAVORABLE NON-BOND ENERGY,STRUCTURES WITH THE LEAST RESTRAINT VIOLATIONS,BACK-CALCULATED DATA AGREE ...コンフォーマー選択の基準: STRUCTURES WITH ACCEPTABLE COVALENT GEOMETRY, STRUCTURES WITH FAVORABLE NON-BOND ENERGY,STRUCTURES WITH THE LEAST RESTRAINT VIOLATIONS,BACK-CALCULATED DATA AGREE WITH EXPERIMENTAL NOESY SPECTRUM 計算したコンフォーマーの数: 100 / 登録したコンフォーマーの数: 10