This tool allows to copy / paste directly an amino sequence as a one letter or 3 letters code. You may also use sequence copied directly from UniProt or Pdb like for example:
SEQRES 1 A 1020 MET LEU SER ALA HIS GLN TRP LEU ARG HIS CYS ILE ILE SEQRES 2 A 1020 GLY VAL ALA SER VAL ALA LEU LEU GLN ALA CYS SER LYS SEQRES 3 A 1020 GLN THR GLY ASN GLU SER SER SER SER ALA LYS SER ALA
10 20 30 40 50 60 MRAMRLRDTT AVAHTLGRKV YSSLKRAAVN NLDLFAGGAA AGAVLLHLLD DVHAAGDLAE