Isolation and characterization of a novel class of plant antimicrobial peptides form Mirabilis jalapa L. seeds.
We have isolated from seeds of Mirabilis jalapa L. two antimicrobial peptides, designated Mj-AMP1 and Mj-AMP2, respectively. These peptides are highly basic and consist of 37 and 36 residues for Mj-AMP1 and Mj-AMP2, respectively. Both peptides contain three disulfide bridges and differ from one another only by 4 amino acids. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the reduced and unreduced peptides suggests that the peptides associate into dimers in their native form. The Mj-AMPs exhibit a broad spectrum of antifungal activity since they are active against all 13 tested plant pathogenic fungi. Concentrations required for 50% inhibition of fungal growth vary from 6 to 300 micrograms/ml for Mj-AMP1 and from 0.5 to 20 micrograms/ml for Mj-AMP2. These peptides were also active on two tested Gram-positive bacteria but were apparently nontoxic for Gram-negative bacteria and cultured human cells. Although the Mj-AMPs show sequence similarity to mu-agatoxins, a class of insecticidal neurotoxic peptides isolated from the venom of spiders, they do not affect pulse transmission in insect nerves.
Cammue
B P
BP
F. A. Janssens Laboratory of Genetics, Catholic University of Leuven, Heverlee, Belgium.
De Bolle
M F
MF
Terras
F R
FR
Proost
P
P
Van Damme
J
J
Rees
S B
SB
Vanderleyden
J
J
Broekaert
W F
WF
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D000935:Antifungal Agents / Q000494:pharmacology; D002478:Cells, Cultured; D002852:Chromatography, Ion Exchange; D003058:Cockroaches / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D004730:Endothelium, Vascular / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009474:Neurons / Q000187:drug effects; D010455:Peptides / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D010940:Plant Proteins / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D012639:Seeds / Q000737:chemistry
C072557:AMP1 protein, Mirabilis jalapa; C072558:AMP2 protein, Mirabilis jalapa; D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D010455:Peptides; D010940:Plant Proteins