Structure of spinach chloroplast F1-ATPase complexed with the phytopathogenic inhibitor tentoxin.
Tentoxin, a natural cyclic tetrapeptide produced by phytopathogenic fungi from the Alternaria species affects the catalytic function of the chloroplast F(1)-ATPase in certain sensitive species of plants. In this study, we show that the uncompetitive inhibitor tentoxin binds to the alphabeta-interface of the chloroplast F(1)-ATPase in a cleft localized at betaAsp-83. Most of the binding site is located on the noncatalytic alpha-subunit. The crystal structure of the tentoxin-inhibited CF(1)-complex suggests that the inhibitor is hydrogen bonded to Asp-83 in the catalytic beta-subunit but forms hydrophobic contacts with residues Ile-63, Leu-65, Val-75, Tyr-237, Leu-238, and Met-274 in the adjacent alpha-subunit. Except for minor changes around the tentoxin-binding site, the structure of the chloroplast alpha(3)beta(3)-core complex is the same as that determined with the native chloroplast ATPase. Tentoxin seems to act by inhibiting inter-subunit contacts at the alphabeta-interface and by blocking the interconversion of binding sites in the catalytic mechanism.
Groth
Georg
G
Heinrich-Heine-Universität, Biochemie der Pflanzen, Universitätsstrasse 1, D-40225 Duesseldorf, Germany. georg.groth@uni-duesseldorf.de
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002736:Chloroplasts / Q000201:enzymology*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008928:Mitochondria / Q000201:enzymology; D008958:Models, Molecular; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D021122:Protein Subunits; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D018724:Spinacia oleracea / Q000201:enzymology*; D013329:Structure-Activity Relationship
D010456:Peptides, Cyclic; D021122:Protein Subunits; D006180:Proton-Translocating ATPases; C003384:tentoxin