TERESIAS is an algorithm that finds motifs within a set of protein sequences. It allows a number of parameters to be specified, delimiting the nature of the motifs reported. These are:

• L The number of fixed positions. That is, how many of the positions in a motif are required to be non-'x'. If this was set to 3, then PxxP would not be found, but PxDLS would be.
• W The maximum length of motifs. Known motifs are typically between 3 and 8 residues in length.
• K Minimum number of sequences required to have the motif. In a large set of sequences, it is to be expected that not all motifs will be found in all sequences. Significant motifs are usually only found if they occur in at least four sequences in a set, but sometimes those occurring three times turn out to be correct.