This tool analyzes tolerance to substitutions at all positions of a protein sequence, searching for correlations with amino acid descriptors.
The main data is a table of:
ΔΔGaa,i = -log(Paa,i/Pwt,i)
where Paa,i = fractional occurrence of amino acid type aa (alphabetically ordered from A=1 to Y=20) at site i in the protein sequence and Pwt,i = fractional occurrence of the 'wild type' (or reference) amino acid.
This tool was originally developed to dissect protein variability data from deep-sequencing experiments as done in this proof-of-concept study but is also helpful for understanding variability in alignments. This other tool converts alignments to ΔΔG data.