Characterization of the interaction of ophiobolin A and calmodulin.
1. The fungal toxin ophiobolin A reacts with the epsilon-amino group of lysine to give a conjugated enamine produce with lambda max at 272 nm and a molar extinction of 19,200 per M/cm. 2. Bovine brain calmodulin reacts with ophiobolin A to give a lambda max at 272 nm. 3. One mol of calmodulin reacts with two moles of ophiobolin A. Reaction of 1 mol of ophiobolin A inactivates 1 mol of calmodulin. 4. Ophiobolin A-treated calmodulin is resistant to tryptic cleavage at lysine 77. 5. Ophiobolin A also inhibits Dictyostelium calmodulin which has glutamine instead of lysine at residue 77.
Leung
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PC
Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.
Graves
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LM
Tipton
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D000818:Animals; D001665:Binding Sites; D001923:Brain Chemistry; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002417:Cattle; D004023:Dictyostelium; D054830:Sesterterpenes; D013056:Spectrophotometry, Ultraviolet; D013729:Terpenes / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism
D002147:Calmodulin; D054830:Sesterterpenes; D013729:Terpenes; C040764:ophiobolin A; D014357:Trypsin