Abstract
A total of 2,245 extracts, derived from 449 marine fungi cultivated in five types of media, were screened against the C(4) plant enzyme pyruvate phosphate dikinase (PPDK), a potential herbicide target. Extracts from several fungal isolates selectively inhibited PPDK. Bioassay-guided fractionation of one isolate led to the isolation of the known compound unguinol, which inhibited PPDK with a 50% inhibitory concentration of 42.3 +/- 0.8 muM. Further kinetic analysis revealed that unguinol was a mixed noncompetitive inhibitor of PPDK with respect to the substrates pyruvate and ATP and an uncompetitive inhibitor of PPDK with respect to phosphate. Unguinol had deleterious effects on a model C(4) plant but no effect on a model C(3) plant. These results indicate that unguinol inhibits PPDK via a novel mechanism of action which also translates to an herbicidal effect on whole plants.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
DNA, Fungal / chemistry
-
DNA, Fungal / genetics
-
DNA, Ribosomal / chemistry
-
DNA, Ribosomal / genetics
-
DNA, Ribosomal Spacer / chemistry
-
DNA, Ribosomal Spacer / genetics
-
Digitaria / drug effects
-
Enzyme Inhibitors / isolation & purification*
-
Enzyme Inhibitors / pharmacology*
-
Fungi / classification
-
Fungi / isolation & purification
-
Fungi / metabolism*
-
Herbicides / isolation & purification*
-
Herbicides / pharmacology*
-
Heterocyclic Compounds, 3-Ring / isolation & purification*
-
Heterocyclic Compounds, 3-Ring / pharmacology*
-
Hordeum / drug effects
-
Kinetics
-
Molecular Sequence Data
-
Phylogeny
-
Protein Binding
-
Pyruvate, Orthophosphate Dikinase / antagonists & inhibitors*
-
RNA, Ribosomal, 18S / genetics
-
Sequence Analysis, DNA
Substances
-
DNA, Fungal
-
DNA, Ribosomal
-
DNA, Ribosomal Spacer
-
Enzyme Inhibitors
-
Herbicides
-
Heterocyclic Compounds, 3-Ring
-
RNA, Ribosomal, 18S
-
unguinol
-
Pyruvate, Orthophosphate Dikinase
Associated data
-
GENBANK/EF067336
-
GENBANK/EF067337