PREdator interface elements. The four interactive analysis windows in PREdator. A) Graphical representation of the original data and the fitted curve. B) Window for selection or deselection of data points that are considered for fitting, drop down menu for fitting function selection, fields for entering initial fitting parameters and experimental error, and entry fields to enter the axis labels for A). C) Graphical summary of one of the selectable fitting parameters over the range of submitted data (e.g. amino acid residues). D) Summary of the resulting fitting parameters, which can be saved as a text file, is shown in the upper text field. The fitting parameter (a,b or c) selected here is displayed over the data range in C). Entry fields to adjust the title and the axis labels for C) are also provided.