Two hevein homologs isolated from the seed of Pharbitis nil L. exhibit potent antifungal activity.
Two antifungal peptides (Pn-AMP1 and Pn-AMP2) have been purified to homogeneity from seeds of Pharbitis nil. The amino acid sequences of Pn-AMP1 (41 amino acid0 residues) and Pn-AMP2 (40 amino acid residues) were identical except that Pn-AMP1 has an additional serine residue at the carboxyl-terminus. The molecular masses of Pn-AMP1 and Pn-AMP2 were confirmed as 4299.7 and 4213.2 Da, respectively. Both the Pn-AMPs were highly basic (pI 12.02) and had characteristics of cysteine/glycine rich chitin-binding domain. Pn-AMPs exhibited potent antifungal activity against both chitin-containing and non-chitin-containing fungi in the cell wall. Concentrations required for 50% inhibition of fungal growth were ranged from 3 to 26 micrograms/ml for Pn-AMP1 and from 0.6 to 75 micrograms/ml for Pn-AMP2. The Pn-AMPs penetrated very rapidly into fungal hyphae and localized at septum and hyphal tips of fungi, which caused burst of hyphal tips. Burst of hyphae resulted in disruption of the fungal membrane and leakage of the cytoplasmic materials. To our knowledge, Pn-AMPs are the first hevein-like proteins that show similar fungicidal effects as thionins do.
Koo
J C
JC
Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Chinju, South Korea.
Lee
S Y
SY
Chun
H J
HJ
Cheong
Y H
YH
Choi
J S
JS
Kawabata
S
S
Miyagi
M
M
Tsunasawa
S
S
Ha
K S
KS
Bae
D W
DW
Han
C D
CD
Lee
B L
BL
Cho
M J
MJ
D000595:Amino Acid Sequence; D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D001419:Bacteria / Q000187:drug effects; D001681:Biological Assay; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005658:Fungi / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D037102:Lectins / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D008970:Molecular Weight; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D012639:Seeds / Q000737:chemistry*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012694:Serine; D013172:Spores, Fungal
D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; C111188:antimicrobial peptide, Pharbitis; C045875:hevein; D012694:Serine