D'Silva I, Heath M C
Department of Botany, University of Toronto, Toronto, Ontario M5S 3B2, Canada.
J Biol Chem. 1997 Feb 14;272(7):3924-7. doi: 10.1074/jbc.272.7.3924.
Two novel elicitor peptides that are produced by the race 1 of the cowpea rust fungus Uromyces vignae and that specifically induce a hypersensitive response (a putative form of programmed cell death) in a resistant cultivar of cowpea (Vigna unguiculata L. Walp) have been purified to homogeneity. Purification steps included gel filtration, anion-exchange chromatography, continuous elution electrophoresis, and reversed-phase C18 high performance liquid chromatography. The relative molecular masses of the peptide elicitors as deduced from Tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis were 5600 Da (major) and 5800 Da (minor), respectively. Peptide 1 (major) and the minor copurifying peptide (peptide 2) resolved at the final C18 high performance liquid chromatography step. The NH2 terminus of peptide 1 was deblocked with anhydrous trifluoroacetic acid prior to sequencing. However, the NH2 terminus of peptide 2 was free. The acidic and hydrophobic peptides show some homology between themselves but do not show any significant similarity with known proteins. The two specific elicitors may be products of two avirulence genes corresponding to the two genes for resistance in the resistant cultivar.
两种由豇豆锈菌（Uromyces vignae）小种1产生的新型激发子肽已被纯化至同质，它们能在豇豆（Vigna unguiculata L. Walp）的一个抗性品种中特异性诱导过敏反应（一种假定的程序性细胞死亡形式）。纯化步骤包括凝胶过滤、阴离子交换色谱、连续洗脱电泳和反相C18高效液相色谱。从十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳推导得出的肽激发子的相对分子质量分别为5600 Da（主要）和5800 Da（次要）。肽1（主要）和次要的共纯化肽（肽2）在最后的C18高效液相色谱步骤中得以分离。在测序之前，用无水三氟乙酸对肽1的NH2末端进行去封闭。然而，肽2的NH2末端是游离的。这些酸性和疏水性肽彼此之间显示出一些同源性，但与已知蛋白质没有任何显著相似性。这两种特异性激发子可能是与抗性品种中的两个抗性基因相对应的两个无毒基因的产物。
