TY - JOUR
T1 - Tricolorin A, a potent natural uncoupler and inhibitor of photosystem II acceptor side of spinach chloroplasts
AU - Achnine, Lahoucine
AU - Pereda-Miranda, Rogelio
AU - Iglesias-Prieto, Roberto
AU - Moreno-Sánchez, Rafael
AU - Lotina-Hennsen, Blas
PY - 1999/6
Y1 - 1999/6
N2 - Tricolorin A, (11S)-11-hydroxyhexadecanoic acid 11-O-α-L-rhamnopyranosyl-(1 → 3)-O-α-L-{2-O-(2S-methylbutanoyl)4-O-(2S-methylhutanoyl)}-rhamnopyranosil- (1 → 2)-O-β-D-glucopyranosil-(l → 2)-β-fucopyranoside-(1,3'-lactone), the major phytogrowth inhibitor isolated from Ipomoea tricolor Cav. (Convolvulaceae) was found to be a potent uncoupler (U50 = 0.33 μM) of photophosphorylation in spinach chloroplasts. Tricolorin A inhibited H+-uptake and adenosine 5'-triphosphate (ATP) synthesis, and stimulated basal and phosphorylating electron flows. Using a combination of two well-known fluorescent ΔpH probes, 9-aminoacridine and 9-amino-6-chloro-2-methoxyacridine, the uncoupling behavior of tricolorin A was also demonstrated for submitochondrial particles. Polarographic data showed that high concentrations (20 μM) of tricolorin A inhibited photosystem II (PSII) electron flow at the level of plastoquinone B (Q(B)). Chlorophyll (Chl) a fluorescence analysis showed that tricolorin A induced accumulation of Q(A)/- and strongly decreased the electron transport capacity, suggesting that the target of this molecule was located at the Q(B) level. The macrocyclic lactone-type structure of this allelopathic agent proved to be an important structural requirement for uncoupling activity since its hydrolysis caused loss of the inhibitory potential.
AB - Tricolorin A, (11S)-11-hydroxyhexadecanoic acid 11-O-α-L-rhamnopyranosyl-(1 → 3)-O-α-L-{2-O-(2S-methylbutanoyl)4-O-(2S-methylhutanoyl)}-rhamnopyranosil- (1 → 2)-O-β-D-glucopyranosil-(l → 2)-β-fucopyranoside-(1,3'-lactone), the major phytogrowth inhibitor isolated from Ipomoea tricolor Cav. (Convolvulaceae) was found to be a potent uncoupler (U50 = 0.33 μM) of photophosphorylation in spinach chloroplasts. Tricolorin A inhibited H+-uptake and adenosine 5'-triphosphate (ATP) synthesis, and stimulated basal and phosphorylating electron flows. Using a combination of two well-known fluorescent ΔpH probes, 9-aminoacridine and 9-amino-6-chloro-2-methoxyacridine, the uncoupling behavior of tricolorin A was also demonstrated for submitochondrial particles. Polarographic data showed that high concentrations (20 μM) of tricolorin A inhibited photosystem II (PSII) electron flow at the level of plastoquinone B (Q(B)). Chlorophyll (Chl) a fluorescence analysis showed that tricolorin A induced accumulation of Q(A)/- and strongly decreased the electron transport capacity, suggesting that the target of this molecule was located at the Q(B) level. The macrocyclic lactone-type structure of this allelopathic agent proved to be an important structural requirement for uncoupling activity since its hydrolysis caused loss of the inhibitory potential.
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U2 - 10.1034/j.1399-3054.1999.106215.x
DO - 10.1034/j.1399-3054.1999.106215.x
M3 - Article
AN - SCOPUS:0032789108
SN - 0031-9317
VL - 106
SP - 246
EP - 252
JO - Physiologia Plantarum
JF - Physiologia Plantarum
IS - 2
ER -