Resolution: 2.92→20 Å / Cor.coef. Fo:Fc: 0.893 / Cor.coef. Fo:Fc free: 0.911 / SU B: 16.582 / SU ML: 0.279 / Cross valid method: THROUGHOUT / ESU R: 0.523 / ESU R Free: 0.293 Details: THE IDENTITY OF THE METAL ION IN THE ACTIVE SITE (LIGATED BY HIS 254 AND ASP 258) IS UNCERTAIN. UNDER PHYSIOLOGICAL CONDITIONS THIS SITE IS MOST LIKELY OCCUPIED BY A MG2+ ION. HOWEVER, SINCE ...Details: THE IDENTITY OF THE METAL ION IN THE ACTIVE SITE (LIGATED BY HIS 254 AND ASP 258) IS UNCERTAIN. UNDER PHYSIOLOGICAL CONDITIONS THIS SITE IS MOST LIKELY OCCUPIED BY A MG2+ ION. HOWEVER, SINCE THE CONCENTRATION OF EDTA IN THE PROTEIN BUFFER EXCEEDS THE MG2+ CONCENTRATION IN THE RESERVOIR BUFFER ALMOST 20 TIMES WE PREDICT THAT THE MG2+ IONS (AND CA2+ IONS THAT WERE ALSO PRESENT IN THE BUFFER) WERE DEPLETED. UNFORTUNATELY, THE RESOLUTION OF THE DIFFRACTION DATA IS NOT HIGH ENOUGH TO PERFORM THE ANALYSIS OF THE METAL-LIGAND DISTANCES, BUT SINCE SODIUM IONS WERE ABUNDANT IN BOTH BUFFERS AND SINCE THE ELECTRON DENSITY LEVEL OF THE ION ROUGHLY CORRESPONDS TO ONE OF THE SURROUNDING PROTEIN AND SOLVENT ATOMS, WE HAVE TENTATIVELY ASSIGNED THE METAL IN THE ACTIVE SITE AS A NA+ ION. HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS
Rfactor
Num. reflection
% reflection
Selection details
Rfree
0.22309
607
4.9 %
RANDOM
Rwork
0.19242
-
-
-
obs
0.19389
11890
96.64 %
-
Solvent computation
Ion probe radii: 0.8 Å / Shrinkage radii: 0.8 Å / VDW probe radii: 1.4 Å