Correlation between occupancy and temperature factors of solvent molecules in crystal structures of proteins

Correlation between occupancy and temperature factors during the refinement of a disordered molecule is discussed on the basis of their effects on an atomic scattering factor curve. When the resolution of the data is limited, occupancy and temperature factors affect scattering-factor curves in a similar fashion, and therefore they are correlated. An examination of this correlation suggests that small deviations (0.1) of occupancy factors from their tentative values may be compensated by suitable changes in temperature factors when the data are limited to medium (2.5 Å) resolution.