The grouping of amino acids to classes and class abbreviation (the key) used within consensus sequences are shown below.
| Class | Key | Residues |
|---|---|---|
| alcohol | o | S,T |
| aliphatic | l | I,L,V |
| any | . | A,C,D,E,F,G,H,I,K,L,M,N,P,Q,R,S,T,V,W,Y |
| aromatic | a | F,H,W,Y |
| charged | c | D,E,H,K,R |
| hydrophobic | h | A,C,F,G,H,I,K,L,M,R,T,V,W,Y |
| negative | - | D,E |
| polar | p | C,D,E,H,K,N,Q,R,S,T |
| positive | + | H,K,R |
| small | s | A,C,D,G,N,P,S,T,V |
| tiny | u | A,G,S |
| turnlike | t | A,C,D,E,G,H,K,N,Q,R,S,T |