Sequence of protein or nucleic acid polymer in standard one-letter
               codes of amino acids or nucleotides. Non-standard amino
               acids/nucleotides are represented by their Chemical
               Component Dictionary (CCD) codes in
               parenthesis. Deoxynucleotides are represented by the
               specially-assigned 2-letter CCD codes in parenthesis,
               with 'D' prefix added to their ribonucleotide
               counterparts. For hybrid polymer, each residue is
               represented by the code of its individual type. A
               cyclic polymer is represented in linear sequence from
               the chosen start to end.
A for Alanine or Adenosine-5'-monophosphate
C for Cysteine or Cytidine-5'-monophosphate
D for Aspartic acid
E for Glutamic acid
F for Phenylalanine
G for Glycine or Guanosine-5'-monophosphate
H for Histidine
I for Isoleucine or Inosinic Acid
L for Leucine
K for Lysine
M for Methionine
N for Asparagine  or Unknown ribonucleotide
O for Pyrrolysine
P for Proline
Q for Glutamine
R for Arginine
S for Serine
T for Threonine
U for Selenocysteine or Uridine-5'-monophosphate
V for Valine
W for Tryptophan
Y for Tyrosine
(DA) for 2'-deoxyadenosine-5'-monophosphate
(DC) for 2'-deoxycytidine-5'-monophosphate
(DG) for 2'-deoxyguanosine-5'-monophosphate
(DT) for Thymidine-5'-monophosphate
(MSE) for Selenomethionine
(SEP) for Phosphoserine
(TPO) for Phosphothreonine
(PTR) for Phosphotyrosine
(PCA) for Pyroglutamic acid
(UNK) for Unknown amino acid
(ACE) for Acetylation cap
(NH2) for Amidation cap