def one_to_full(one_letter):
    """
    Convert one-letter amino acid code to full amino acid name.
    """
    assert one_letter.upper() in "FLSYCWPHERIMTNKVADQG*U", "Error, %s is not a valid amino acid" % one_letter
    AA = {
        "F": "Phenylalanine",
        "L": "Leucine",
        "S": "Serine",
        "Y": "Tyrosine",
        "*": "Stop",
        "C": "Cysteine",
        "W": "Tryptophan",
        "P": "Proline",
        "H": "Histidine",
        "Q": "Glutamine",
        "R": "Arginine",
        "I": "Isoleucine",
        "M": "Methionine",
        "T": "Threonine",
        "N": "Asparagine",
        "K": "Lysine",
        "V": "Valine",
        "A": "Alanine",
        "D": "Aspartic acid",
        "E": "Glutamic acid",
        "G": "Glycine",
        "U": "Unnatural AA",
    }
    return AA[one_letter.upper()]