| DISTANCE GEOMETRY, RESTRAINED ENERGY REFINEMENT | REFINEMENT DETAILS CAN BE FOUND IN THE JRNL CITATION ABOVE. THREE-DIMENSIONAL STRUCTURE IN AQUEOUS SOLUTION REPRESENTED BY 20 CONFORMERS DETERMINED BY NUCLEAR MAGNETIC RESONANCE, DISTANCE GEOMETRY AND RESTRAINED ENERGY REFINEMENT. DATA WERE COLLECTED AT 23 DEGREES CELSIUS AND AT PH 5.0. THEY CONSIST OF 497 UPPER LIMITS ON DISTANCES OBTAINED FROM NOE MEASUREMENTS AND 41 ANGLE CONSTRAINTS OBTAINED FROM NOE MEASUREMENTS AND COUPLING CONSTANT MEASUREMENTS. THESE INPUT DATA ARE ALSO AVAILABLE FROM THE PROTEIN DATA BANK. DISTANCE GEOMETRY CALCULATIONS WERE PERFORMED WITH THE PROGRAM DIANA (P. GUENTERT, W. BRAUN, K. WUTHRICH, J. MOL. BIOL. (1991) VOL. 217, 517 - 530). FOR THE RESTRAINED ENERGY MINIMIZATION THE PROGRAM OPAL (P. LUGINBUHL ET AL., J. BIOMOL. NMR (1996) VOL. 8, 136-146) WAS USED. FOR THE PRESENT STRUCTURES THE NMR DISTANCE CONSTRAINTS WERE WEIGHTED SUCH THAT A VIOLATION OF AN UPPER DISTANCE LIMIT OF 0.1 ANGSTROM CORRESPONDS TO AN ENERGY OF KT/2. THE CONSTRAINTS ON DIHEDRAL ANGLES RESULTING FROM MEASUREMENTS OF VICINAL COUPLING CONSTANTS WERE WEIGHTED SUCH THAT A VIOLATION OF 2.5 DEGREES CORRESPONDS TO AN ENERGY OF KT/2. DEPOSITED COORDINATES ARE THOSE OF CONFORMERS 1 - 20 IN THE PAPER CITED ON *JRNL* RECORDS ABOVE. NO VIOLATIONS OF DISTANCE CONSTRAINTS FROM NOES EXCEED 0.10 ANGSTROMS, AND NO VIOLATIONS OF ANGLE CONSTRAINTS EXCEED 2.5 DEGREES. ATOM NAMES HAVE BEEN ASSIGNED FOLLOWING THE RECOMMENDATIONS OF THE IUPAC-IUB COMMISSION AS PUBLISHED IN BIOCHEMISTRY (1970) VOL. 8, 3471 - 3479. THE INDIVIDUAL NUMBERS OF THE HYDROGEN ATOMS IN METHYL AND METHYLENE GROUPS ARE INDICATED AS THE FIRST CHARACTER RATHER THAN THE LAST CHARACTER OF THE ATOM NAMES. THE AVERAGE OF THE RMSD VALUES IN A PAIRWISE COMPARISON OF THE 20 NMR CONFORMERS TO THE MEAN STRUCTURE AS DESCRIBED IN THE PAPER CITED ON * JRNL* RECORDS ABOVE IS 0.47 ANGSTROMS FOR THE BACKBONE ATOMS OF RESIDUES 1 - 37, AND 0.75 ANGSTROMS FOR ALL HEAVY ATOMS. EXCLUDING THE CARBOXY-TERMINUS AND THE AMINO-TERMINUS, WHICH ARE LESS WELL DEFINED BY THE NMR DATA, THE AVERAGE OF THE RMSD VALUES IN A PAIRWISE COMPARISON TO THE MEAN STRUCTURE FOR RESIDUES 2 - 32 IS 0.27 ANGSTROMS FOR THE BACKBONE ATOMS. | OPAL |
