| NMR-RESTRAINED SIMULATED ANNEALING, MOLECULAR DYNAMICS, AND ENERGY MINIMIZATION. |
NMR DISTANCE RESTRAINTS WERE ASSIGNED WITH THE AID OF ARIA (AMBIGUOUS RESTRAINTS FOR ITERATIVE ASSIGNMENT) PROCEDURE, RESULTING IN 2778 UNAMBIGUOUS AND 306 AMBIGUOUS DISTANCE RESTRAINTS. 63 J COUPLING CONSTANTS, AND 44 HYDROGEN BOND RESTRAINTS WERE ALSO USED IN THE STRUCTURE CALCULATIONS. 100 STRUCTURES WERE CALCULATED USING XPLOR NMR- RESTRAINED SIMULATED ANNEALING PROTOCOL. RESIDUES 112-231 OF THE 25 STRUCTURES WITH LOWEST TOTAL ENERGY WERE EACH SUBJECTED TO 25PS RESTRAINED MOLECULAR DYNAMICS SIMULATION IN A 6 ANGSTROM SHELL OF WATER FOLLOWED BY ENERGY MINIMIZATION USING AMBER4.1 FORCE FIELD. THE AVERAGE VIOLATION FOR DISTANCE RESTRAINTS IS 0.032A, AND FOR J COUPLING CONSTANTS IS 0.059HZ. THE AVERAGE BACKBONE ATOMIC RMSD TO THE MEAN STRUCTURE IS 0.67A FOR RESIDUES 125-227 OF THE 25 STRUCTURES. THE REFINEMENT HAS BEEN SUBMITTED TO BIOCHEMISTRY WITH THE TITLE "SOLUTION STRUCTURE OF SYRIAN HAMSTER PRION PROTEIN RPRP(90-231)". NOTE, LOWER RESOLUTION STRUCTURES PUBLISHED ON PNAS 94, 10086 (1997) WERE CALCULATED WITH THE PROGRAM DIANA DEVELOPED IN WUTHRICH'S LAB.RESIDUES 90-124 OF RPRP(90-231) ARE LARGELY UNSTRUCTURED. RESIDUES 90-111 WERE EXCLUDED IN THE FINAL STAGE OF STRUCTURE REFINEMENT. THE COORDINATES DEPOSITED TO PDB CONTAIN RESIDUES 125-228. |
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