Signal peptide homology between the sweet protein thaumatin II and unrelated cereal alpha-amylase/trypsin inhibitors.
A cDNA clone (pUP-23) corresponding to a member of a protein family that includes inhibitors of trypsin and of heterologous alpha-amylases has been selected from a library derived from developing barley endosperm and its sequence has been determined. A stretch of 95 nucleotides that included the signal peptide and the first 8 residues of the mature protein was found to be homologous to an exactly equivalent region of the nucleotide sequence encoding the sweet protein thaumatin II. Evolutionary implications of this finding are discussed.
Lázaro
A
A
Cátedra de Bioquímica y Biología Molecular, ETS Ingenieros Agrónomos-UPM, Madrid, Spain.
Rodriguez-Palenzuela
P
P
Maraña
C
C
Carbonero
P
P
Garcia-Olmedo
F
F
D000595:Amino Acid Sequence; D000681:Amylases / Q000037:antagonists & inhibitors* / Q000235:genetics; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D001467:Hordeum / Q000235:genetics; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics*; D021382:Protein Sorting Signals / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013549:Sweetening Agents; D014908:Triticum / Q000235:genetics; D014361:Trypsin Inhibitors / Q000235:genetics*; D000516:alpha-Amylases / Q000037:antagonists & inhibitors
D010940:Plant Proteins; D021382:Protein Sorting Signals; D013549:Sweetening Agents; D014361:Trypsin Inhibitors; C057542:thaumatin II protein, Thaumatococcus daniellii; D004247:DNA; D000681:Amylases; D000516:alpha-Amylases