PSAM

PSAM is an abbreviation in bioinformatics and means position-specific affinity matrix .

The PSAM illustrates the tendency of a transcription factor to bind to a nucleotide sequence with a certain length L. The matrix has a size of 4xL. There are four lines in which the respective binding tendency value to a nucleobase , i.e. adenine (A), guanine (G), cytosine (C), thymine (T) or uracil (U), is noted at the corresponding point in the nucleotide sequence. The highest slope value at the corresponding point in the nucleotide sequence is always scaled to 1 in order to identify the nucleobase that is most likely to bind. From the finished PSAM it is quickly possible to see which nucleotide sequence a transcription factor is likely to bind to and how high the energy of the tendency to bind to the nucleobase is. In bioinformatics, the PSAMs are mostly generated automatically by algorithms . In connection with the matrix, a so-called affinity logo is often offered to graphically visualize the PSAM.