Nucleotides
| Symbol | Meaning | Origin of designation |
|---|---|---|
| a | a | adenine |
| g | g | guanine |
| c | c | cytosine |
| t | t | thymine |
| u | u | uracil |
| r | g or a | purine |
| y | t/u or c | pyrimidine |
| m | a or c | amino |
| k | g or t/u | keto |
| s | g or c | strong interactions 3H-bonds |
| w | a or t/u | weak interactions 2H-bonds |
| b | g or c or t/u | not a |
| d | a or g or t/u | not c |
| h | a or c or t/u | not g |
| v | a or g or c not t | not u |
| n | a or g or c or t/u | unknown or other |
Amino acids
| 1-letter code | 3-letter code | Meaning |
|---|---|---|
| A | Ala | Alanine |
| C | Cys | Cysteine |
| D | Asp | Aspartic Acid |
| E | Glu | Glutamic Acid |
| F | Phe | Phenylalanine |
| G | Gly | Glycine |
| H | His | Histidine |
| I | Ile | Isoleucine |
| K | Lys | Lysine |
| L | Leu | Leucine |
| M | Met | Methionine |
| N | Asn | Asparagine |
| P | Pro | Proline |
| Q | Gln | Glutamine |
| R | Arg | Arginine |
| S | Ser | Serine |
| T | Thr | Threonine |
| V | Val | Valine |
| W | Trp | Tryptophan |
| Y | Tyr | Tyrosine |
| B | Asx | Asp or Asn |
| Z | Glx | Glu or Gln |
| X | Xaa | unknown or other |