Schmitt M, Radler F
Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-Universität Mainz, Federal Republic of Germany.
J Bacteriol. 1988 May;170(5):2192-6. doi: 10.1128/jb.170.5.2192-2196.1988.
The adsorption of the yeast killer toxin KT28 to susceptible cells of Saccharomyces cerevisiae was prevented by concanavalin A, which blocks the mannoprotein receptor. Certain mannoprotein mutants of S. cerevisiae that lack definite structures in the mannan of their cell walls were found to be resistant to KT28, whereas the wild-type yeast from which the mutants were derived was susceptible. Isolated mannoprotein from a resistant mutant was unable to adsorb killer toxin. By comparing the resistances of different mannoprotein mutants, information about the molecular structure of the receptor was obtained. At least two mannose residues have to be present in the side chains of the outer chain of the cell wall mannan, whereas the phosphodiester-linked mannose group is not essential for binding and the subsequent action of killer toxin KT28.
伴刀豆球蛋白A可阻止酵母杀伤毒素KT28吸附到酿酒酵母的敏感细胞上，因为它会阻断甘露糖蛋白受体。已发现酿酒酵母的某些甘露糖蛋白突变体，其细胞壁甘露聚糖中缺乏明确结构，对KT28具有抗性，而衍生出这些突变体的野生型酵母则敏感。从抗性突变体中分离出的甘露糖蛋白无法吸附杀伤毒素。通过比较不同甘露糖蛋白突变体的抗性，获得了有关受体分子结构的信息。细胞壁甘露聚糖外链的侧链中必须至少存在两个甘露糖残基，而磷酸二酯连接的甘露糖基团对于杀伤毒素KT28的结合及后续作用并非必需。
