Hi, I am refining two crystal structures of the same protein wtih four domains and 687 amino acids. These are the last lines form my log-files after several model building steps - protein altogether fits quite well into the density. But I am confused about these logfiles: 1.Why is there such a big difference between R values with and without bulk solvent correction and anisotropic scale? Start R-work = 0.3765, R-free = 0.5498 (no bulk solvent and anisotropic scale) Final R-work = 0.3733, R-free = 0.5509 (no bulk solvent and anisotropic scale) Start R-work = 0.2356, R-free = 0.2962 Final R-work = 0.2250, R-free = 0.2939 2. (the other structure) Why does the R value without bulk solvent and anisotropic scale decrease so much but with it remains stable? Start R-work = 0.2182, R-free = 0.2856 (no bulk solvent and anisotropic scale) Final R-work = 0.4054, R-free = 0.4223 (no bulk solvent and anisotropic scale) Start R-work = 0.2157, R-free = 0.2827 Final R-work = 0.2147, R-free = 0.2816 I would be very pleased about any helpful comments. Ina Ina Lindemann Philipps-Universität Marburg Pharmazeutische Chemie AG Klebe Marbacher Weg 6 35032 Marburg Tel.: 06421/2825908