Chorismate synthase (EC 4.6.1.4) catalyses the conversion of 5-enolpyruvylshikimate 3-phosphate (EPSP) into chorismate, and requires reduced FMN as a cofactor. The enzyme can bind first oxidized FMN and then EPSP to form a stable ternary complex which does not undergo turnover. This complex can be considered to be a model of the ternary complex between enzyme, EPSP and reduced FMN immediately b...

We are studying two enzymes from the shikimate pathway, dehydroquinate synthase (DHQS) and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Both enzymes have been the subject of numerous studies to elucidate their reaction mechanisms. Crystal structures of DHQS and EPSPS in the presence and absence of substrates, cofactors and/or inhibitors are now available. These structures reveal movemen...

Evolved herbicide resistance (EHR) is an important agronomic problem and consequently a food security problem, as it jeopardizes herbicide effectiveness and increases the difficulty and cost of weed management. EHR in weeds was first reported in 1970 and the number of cases has accelerated dramatically over the last two decades. Despite 40 years of research on EHR, why some weeds evolve resista...

In eubacteria, green algae, and plant chloroplasts, isopentenyl diphosphate, a key intermediate in the biosynthesis of isoprenoids, is synthesized by the methylerythritol phosphate pathway. The five carbons of the basic isoprenoid unit are assembled by joining pyruvate and D-glyceraldehyde 3-phosphate. The reaction is catalyzed by the thiamine diphosphate-dependent enzyme 1-deoxy-D-xylulose 5-p...

We have previously cloned a gene for a zinc finger protein (EPF1) that is expressed specifically in petals and interacts with the promoter region of the 5-enolpyruvylshikimate-3-phosphate synthase gene in petunia. In an attempt to isolate genes encoding additional factors that interact with this promoter, we cloned four novel genes encoding zinc finger proteins (EPF2-5a, EPF2-5b, EPF2-4, and EP...

It is not clear why herbicides targeting aromatic and branched-chain amino acid biosynthesis successfully control broomrapes-obligate parasitic plants that obtain all of their nutritional requirements, including amino acids, from the host. Our objective was to reveal the mode of action of imazapic and glyphosate in controlling the broomrape Phelipanche aegyptiaca and clarify if this obligatory ...

Herbicides inhibit enzymatic systems of plants. Acetolactate synthase (ALS, EC = 4.1.3.18) and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, EC 2.5.1.19) are key enzymes for herbicide action. Hundreds of compounds inhibit ALS. This enzyme is highly variable, enabling the selective control of weeds in a number of crops. Glyphosate, the only commercial herbicide inhibiting EPSPS is widely u...

In which cells of the flower volatile biosynthesis takes place is unclear. In rose and snapdragon, some enzymes of the volatile phenylpropanoid/benzenoid pathway have been shown to be present in the epidermal cells of petals. It is therefore generally believed that the production of these compounds occurs in these cells. However, whether the entire pathway is active in these cells and whether i...