Antimicrobial peptides from Amaranthus caudatus seeds with sequence homology to the cysteine/glycine-rich domain of chitin-binding proteins.
Two antimicrobial peptides (Ac-AMP1 and Ac-AMP2) were isolated from seeds of amaranth (Amaranthus caudatus), and their physicochemical and biological properties were characterized. On the basis of fast atom bombardment mass spectroscopy, Ac-AMP1 and Ac-AMP2 have monoisotopic molecular masses of 3025 and 3181, respectively. Both proteins have pI values above 10. The amino acid sequence of Ac-AMP1 (29 residues) is identical to that of Ac-AMP2 (30 residues), except that the latter has 1 additional residue at the carboxyl terminus. The sequences are highly homologous to the cysteine/glycine-rich domain occurring in many chitin-binding proteins. Both Ac-AMP1 and Ac-AMP2 bind to chitin in a reversible way. Ac-AMP1 and Ac-AMP2 inhibit the growth of different plant pathogenic fungi at much lower doses than other known antifungal chitin-binding proteins. In addition, they show some activity on Gram-positive bacteria. The antimicrobial effect of Ac-AMP1 and Ac-AMP2 is strongly antagonized by cations.
Broekaert
W F
WF
F. A. Janssens Laboratory of Genetics, Catholic University of Leuven, Heverlee, Belgium.
Mariën
W
W
Terras
F R
FR
De Bolle
M F
MF
Proost
P
P
Van Damme
J
J
Dillen
L
L
Claeys
M
M
Rees
S B
SB
Vanderleyden
J
J
D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000737:chemistry*; D023181:Antimicrobial Cationic Peptides; D002118:Calcium / Q000494:pharmacology; D002686:Chitin / Q000378:metabolism*; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides; D006094:Gram-Positive Bacteria / Q000187:drug effects; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry* / Q000494:pharmacology; D010944:Plants / Q000737:chemistry; D011188:Potassium / Q000494:pharmacology; D012639:Seeds / Q000737:chemistry*
D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D004220:Disulfides; D010940:Plant Proteins; C074242:AMP2 protein, Amaranthus caudatus; D002686:Chitin; D003545:Cysteine; D011188:Potassium; D002118:Calcium