Changes of the scaling B-factor (Brel) for datasets in a particular data series: (a) thaumatin, (b) Au-derivatized elastase, (c) Pt-derivatized elastase, (d) Lon protease, (e) thermolysin. Each green triangle represents the value of the scaling B-factor for a particular dataset. Orange squares represent the linear regression fit with the scaling B-factor values representing the dependent variable and the elements of the first eigenvector representing the independent variable set. The linear regression was performed for thermolysin (R = 0.986) and both versions of elastase crystals (R = 0.988 for Pt-derivatized elastase and R = 0.984 for Au-derivatized elastase). In the case of thaumatin and Lon protease, elements of the first two eigenvectors were used for multiple linear regression with R = 0.987 for thaumatin and R = 1.000 for Lon protease. The excellent fit in all cases shows that the physical interpretation of the first and sometimes the first and second eigenvectors as representing effects arising from specific radiation changes agrees well with the increase of the scaling B-factor, a physical quantity, which is directly related to the radiation-induced decay. In (a) the brown diamonds and the blue circles represent the elements of the first (brown) and the second (blue) eigenvectors scaled by their singular values.