Time filter

Source Type

Frankfurt am Main, Germany

He Y.-P.,Max Planck Institute of Molecular Physiology | He Y.-P.,TU Dortmund | Tan H.,Max Planck Institute of Molecular Physiology | Tan H.,TU Dortmund | And 11 more authors.
Chemistry - An Asian Journal | Year: 2011

A full account on the synthesis of the antibiotic natural product biphenomycin B and several derivatives is reported, which employs a Suzuki coupling reaction of a free carboxylic acid and macrolactam formation as key transformations. Liberal exchange of the central amino acid was demonstrated. This procedure gave derivatives to study the influence of the polar side chain of the central amino acids on translation inhibition. A flexible synthesis of the natural product antibiotic biphenomycin B is described. The key transformations are a Suzuki coupling reaction of a free carboxylic acid and macrolactam formation. The synthesis provided derivatives, which were studied for their influence on bacterial translation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pavlidi N.,University of Crete | Tseliou V.,University of Crete | Riga M.,University of Crete | Nauen R.,BayerCropScience AG | And 4 more authors.
Pesticide Biochemistry and Physiology | Year: 2015

The two-spotted spider mite Tetranychus urticae is one of the most important agricultural pests world-wide. It is extremely polyphagous and develops resistance to acaricides. The overexpression of several glutathione S-transferases (GSTs) has been associated with insecticide resistance. Here, we functionally expressed and characterized three GSTs, two of the delta class (TuGSTd10, TuGSTd14) and one of the mu class (TuGSTm09), which had been previously associated with striking resistance phenotypes against abamectin and other acaricides/insecticides, by transcriptional studies. Functional analysis showed that all three GSTs were capable of catalyzing the conjugation of both 1-chloro-2,4 dinitrobenzene (CDNB) and 1,2-dichloro-4-nitrobenzene(DCNB) to glutathione (GSH), as well as exhibiting GSH-dependent peroxidase activity toward Cumene hydroperoxide (CumOOH). The steady-state kinetics of the T. urticae GSTs for the GSH/CDNB conjugation reaction were determined and compared with other GSTs. The interaction of the three recombinant proteins with several acaricides and insecticides was also investigated. TuGSTd14 showed the highest affinity toward abamectin and a competitive type of inhibition, which suggests that the insecticide may bind to the H-site of the enzyme. The three-dimensional structure of the TuGSTd14 was predicted based on X-ray structures of delta class GSTs using molecular modeling. Structural analysis was used to identify key structural characteristics and to provide insights into the substrate specificity and the catalytic mechanism of TuGSTd14. © 2015 Elsevier Inc.

Lummen P.,BayerCropScience AG | Khajehali J.,Ghent University | Luther K.,BayerCropScience AG | Van Leeuwen T.,Ghent University | Van Leeuwen T.,University of Amsterdam
Insect Biochemistry and Molecular Biology | Year: 2014

Acetyl-CoA carboxylase (ACC) catalyzes the committed and rate-limiting step in fatty acid biosynthesis. The two partial reactions, carboxylation of biotin followed by carboxyl transfer to the acceptor acetyl-CoA, are performed by two separate domains in animal ACCs.The cyclic keto-enol insecticides and acaricides have been proposed to inhibit insect ACCs. In this communication, we show that the enol derivative of the cylic keto-enol insecticide spirotetramat inhibited ACCs partially purified from the insect species Myzus persicae and Spodoptera frugiperda, as well as the spider mite (. Tetranychus urticae) ACC which was expressed in insect cells using a recombinant baculovirus. Steady-state kinetic analysis revealed competitive inhibition with respect to the carboxyl acceptor, acetyl-CoA, indicating that spirotetramat-enol bound to the carboxyltransferase domain of ACC. Interestingly, inhibition with respect to the biotin carboxylase substrate ATP was uncompetitive.Amino acid residues in the carboxyltransferase domains of plant ACCs are important for binding of established herbicidal inhibitors. Mutating the spider mite ACC at the homologous positions, for example L1736 to either isoleucine or alanine, and A1739 to either valine or serine, did not affect the inhibition of the spider mite ACC by spirotetramat-enol. These results indicated different binding modes of the keto-enols and the herbicidal chemical families. © 2014 Elsevier Ltd.

Carr J.L.,Imperial College London | Offermann D.A.,Imperial College London | Holdom M.D.,Kings College London | Dusart P.,Kings College London | And 6 more authors.
Chemical Communications | Year: 2010

The total syntheses of (±)-aspercyclide A (1) and its C19 methyl ether (15a) featuring Heck-Mizoroki macrocyclisation to form the 11-membered (E)-styrenyl biaryl ether lactone core are described. © The Royal Society of Chemistry 2010.

The present invention relates to the use of new and known dithiine derivatives for controlling unwanted microorganisms, more particularly phytopathogenic fungi, in crop protection, in the household and hygiene sector and in the protection of materials, and also to new dithiine derivatives, to processes for preparing them, to their use, and to crop protection compositions comprising these new dithiine derivatives.

Discover hidden collaborations