Strobilurins transportation

With the introduction of Be 1 complex inhibitors (Chapter 13.2) in 1996, which act on the electron transport of fungi cells, the most important new compound class called strobilurins, derived from the natural compound Strobilurin A, was introduced in the reference period to the market. Chapter 13 describes the biochemistry of oxidative phosphorylation and of the related compounds and compound classes acting at different sites, reflecting the importance of these targets for the fungicide market nowadays. At the same time it became evident that resistance development, e.g., in the compound class of strobilurins must not lead necessarily to the abandonment of the marketing, research and development of such chemistry. 

Fluacrypyrim (73 2002, Titaron , Nippon Soda) [118] is the first strobilurin analogue to be marketed as an acaricide rather than a fungicide - it inhibits mitochondrial electron transport at complex III of the respiratory chain. It is active against all growth stages of spider mites and shows an acaricidal contact and... 

Strobilurins halt the production of ATP by blocking the electron transport at the level of the be,-complex, located within the mitochondrial Inner membrane, which separates the matrix from the intermembrane space (transmission electron microscope image). In a process, the so-called Q cycle, which was first proposed by the British biochemist Peter Dennis Mitchell (1920-1992), ubihydroquinone (also known as ubiquinol) is oxidized to ubiquinone, thereby transfering an electron to each, the Rieske iron-sulfur complex and the bi heme. While this cycle operates twice, four protons in total are pumped into the intermembrane space, and generate a proton gradient. 

It could be shown that strobilurins and oudemansins as well as myxothiazol A disrupt the electron transport at the bcj-complex (Fig. 8.15). [40] The )- -methoxyacrylate moiety is the essential toxicophore and interacts reversibly with cytochrome bL at the outer ubihydroquinone oxidation centre (Qo). Detailed biochemical and structural biology data have been generated, which provide good experimental evidence of how this so-called Qol group of inhibitors operates at the molecular level. 

Figure 3. Calculated Transportation Stream Concentration Factor (TSCF) for Selected Strobilurins in Barley...

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