de Boer A H, Watson B A, Cleland R E
University of Washington, Department of Botany, Seattle 98195, USA.
Plant Physiol. 1989;89(1):250-9. doi: 10.1104/pp.89.1.250.
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.
壳梭孢菌素（FC）是一种真菌植物毒素，可刺激高等植物质膜（PM）中的H(+) -ATP酶。导致H(+) 外流增强的反应链中的第一个事件似乎是FC与质膜中的FC结合蛋白（FCBP）结合。我们用1%辛基葡糖苷以活性形式从燕麦（燕麦品种胜利）根质膜中溶解了90%的FCBP。蛋白酶抑制剂的存在使FCBP得以稳定。通过使用FC连接的己二酸二酰肼琼脂糖（FC-AADA）的亲和色谱法纯化FCBP。用8摩尔尿素洗脱后，在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上获得了两条主要蛋白带，分子量分别为29,700和31,000。当用十二烷基硫酸钠洗脱FC-AADA时，在BBAB Bio-Gel A、己基琼脂糖和FC-AADA上进行连续色谱分离得到了相同的两条带。3H-FC结合活性与这两条蛋白带的存在之间存在直接相关性。分子量为29,700和31,000的条带的化学计量比为1:2。这表明FCBP以天然形式作为一种表观分子量约为92,000的异源三聚体存在。
