Purification and identification of the fusicoccin binding protein from oat root plasma membrane.
Fusicoccin (FC), a fungal phytotoxin, stimulates the H(+) -ATPase located in the plasma membrane (PM) of higher plants.  The first event in the reaction chain leading to enhanced H(+) -efflux seems to be the binding of FC to a FC-binding protein (FCBP) in the PM.  We solubilized 90% of the FCBP from oat (Avena sativa L. cv Victory) root PM in an active form with 1% octyl-glucoside.  The FCBP was stabilized by the presence of protease inhibitors.  The FCBP was purified by affinity chromatography using FC-linked adipic acid dihydrazide agarose (FC-AADA).  Upon elution with 8 molar urea, two major protein bands on sodium dodecyl sulfate-polyaerylamide gel electrophoresis with molecular weights of 29,700 and 31,000 were obtained.  Successive chromatography on BBAB Bio-Gel A, hexyl agarose, and FC-AADA resulted in the same two bands when the FC-AADA was eluted with sodium dodecyl sulfate.  A direct correlation was made between 3H-FC-binding activity and the presence of the two protein bands.  The stoichiometry of the 29,700 and 31,000 molecular weight bands was 1:2.  This suggests that the FCBP occurs in the native form as a heterotrimer with an apparent molecular weight of approximately 92,000.
de Boer
A H
AH
University of Washington, Department of Botany, Seattle 98195, USA.
Watson
B A
BA
Cleland
R E
RE
D018554:Avena / Q000737:chemistry* / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006027:Glycosides / Q000494:pharmacology; D008970:Molecular Weight; D009183:Mycotoxins / Q000494:pharmacology; D010940:Plant Proteins; D018517:Plant Roots / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000502:physiology; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D013696:Temperature; D014357:Trypsin / Q000494:pharmacology
D006027:Glycosides; D009183:Mycotoxins; D010940:Plant Proteins; D011480:Protease Inhibitors; D011956:Receptors, Cell Surface; C080425:fusicoccin receptor protein, plant; C007808:fusicoccin; D014357:Trypsin; D006180:Proton-Translocating ATPases