Hi All, I have been refining the mutant structures and at the end while making the comparative study I found that there is a large difference (almost half) number of water molecules in the protein strucutre of same mutant from different crystal conditions. The resolution of the structure, space group and no.of molecules in a.s.u is same. Here is the data collection statistics and no.of water & protein atoms present. I could also not understand the difference of unique and measured reflections at same resolution. Could anyone please explain me? Resolution range (Å) 20-1.6 (1.64-1.60) 20-1.8 (1.85-1.80) 20-1.9 (1.99-1.94) 20-1.6 (1.63-1.59) 20-1.6 (1.64-1.60) Number of measured reflections 221864 (14118) 173933 (9556) 85976 (5129) 206723 (12667) 262291 (15803) Unique reflections 84896 (6139) 59955 (4010) 38628 (2777) 86161 (5992) 85305 (5803) Completeness (%) 98.7 (97.2) 95.9 (87.9) 77.6 (75.5) 93.9 (87.9) 97.8 (90.9) No of protein atoms 5101 5096 5076 5113 5120 No of waters 1103 528 453 585 1214 Thanx, World