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Mode of action of novel 2-(benzylamino)-4-methyl-6-(trifluoro-methyl)-1,3,5-triazine herbicides: inhibition of photosynthetic electron transport and binding studies

Ohki, A., Kuboyama, N., Koizumi, K., Tanaka, A., Sato, Y., Kohno, H., Boger, P., Wakabayashi, K.
Journal of agricultural and food chemistry 1999 v.47 no.10 pp. 4398-4402
Chenopodium album, Spinacia oleracea, triazine herbicides, atrazine, herbicidal properties, photosynthesis, structure-activity relationships, plant proteins, thylakoids, electron transfer, D1 protein
Novel 2-(benzylamino)-4-methyl-6- (trifluoromethyl)-1,3,5-triazines have the same 1,3,5-triazine skeleton as atrazine, although some of them, for example, 2-(3-chlorobenzylamino)-4-methyl-6- (trifluoromethyl)-1,3,5-triazine [pI(50)(spinach) = 7.21], show a >3 times stronger photosynthetic electron transport inhibitory activity than atrazine [pI(50)(spinach) = 6.72]. The new triazines have only one amino group at the triazine ring, and their molecular shapes are different from atrazine. The replacement of the bound [(14)C]atrazine by 1,3,5-triazines was tested to determine whether the novel 1,3,5-triazine analogues exhibit the same binding pattern at the D1-protein as atrazine. It was found that [(14)C]atrazine bound to the Di-protein was replaced by the triazine tested by a clearly competitive interaction. Obviously, the novel 1,3,5 -triazines are attached to the same binding niche as atrazine.