• 4.6 Nucleotides and Amino Acid nomenclature [7]
    The nucleotide and amino acid symbols using in this database follow the Nomenclature for Incompletely Specified Bases in Nucleic Acid Sequences (see IUBMB (NC-IUB)) as the DNA and amino acid nomenclature of the HGVS (Human Genome Variation Society) recommends [7].
    DNA [8-12]:
    Symbol Meaning Description
    A A Adenine
    C C Cytosine
    G G Guanine
    T T Thymine
    B C, G or T not-A (B follows A in alphabet)
    D A, G or T not-C (D follows C in alphabet)
    H A, C or T not-G (H follows G in alphabet)
    K G or T Keto
    M A or C aMino
    N A, C, G or T aNy
    R A or G puRine
    S G or C Strong interaction (3 H-bonds)
    V A, C or G not-T / not-U ( V follows U )
    W A or T Weak interaction (2 H-bonds)
    Y C or T pYrimidine
    Amino Acid and protein [13-15]:
    Amino acid Single-letter code Triplet (5'-3') Possible Genotic Codons
    Terminator . TRR (TAR and TGA) TAA, TAG, TGA (translation termination)
    Alanine A GCN GCA, GCC, GCG, GCT
    Aspartic acid or asparagine B RAY AAC, AAT, GAC, GAT
    Cysteine C TGY TGC, TGT
    Aspartic acid D GAY GAC, GAT
    Glutamic acid E GAR GAA, GAG
    Phenylalanine F TTY TTC, TTT
    Glycine G GGN GGA, GGC, GGG, GGT
    Histidine H CAY CAC, CAT
    Isoleucine I ATH ATA, ATC, ATT
    Lysine K AAR AAA, AAG
    Leucine L YTN (CTN and TTR) CTA, CTC, CTG, CTT, TTA, TTG
    Methionine M ATG ATG (translation initiation)
    Asparagine N AAY AAC, AAT
    Proline P CCN CCA, CCC, CCG, CCT
    Glutamine Q CAR CAA, CAG
    Arginine R MGN (CGN and AGR) AGA, AGG, CGA, CGC, CGG, CGT
    Serine S WSN (TCN and AGY) AGC, AGT, TCA, TCC, TCG, TCT
    Threonine T ACN ACA, ACC, ACG, ACT
    Selenocysteine U Sec TGA
    Valine V GTN GTA, GTC, GTG, GTT
    Tryptophan W TGG TGG
    Unknown X NNN NNN
    Tyrosine Y TAY TAC, TAT
    Glutamic acid or glutamine Z SAR