Fils-Lycaon B R, Wiersma P A, Eastwell K C, Sautiere P
Institut National de la Recherche Agronomique, Agroparc, Domaine Saint Paul, Station de Technologie des Produits Végétaux, Avignon, France.
Plant Physiol. 1996 May;111(1):269-73. doi: 10.1104/pp.111.1.269.
A 29-kD polypeptide is the most abundant soluble protein in ripe cherry fruit (Prunus avium L); accumulation begins at the onset of ripening as the fruit turns from yellow to red. This protein was extracted from ripe cherries and purified by size-exclusion and ion-exchange chromatography. Antibodies to the purified protein were used to screen a cDNA library from ripe cherries. Numerous recombinant plaques reacted positively with the antibodies; the DNA sequence of representative clones encoded a polypeptide of 245 amino acid residues. A signal peptide was indicated, and the predicted mature protein corresponded to the purified protein in size (23.3 kD, by mass spectrometry) and isoelectric point (4.2). A search of known protein sequences revealed a strong similarity between this polypeptide and the thaumatin family of pathogenesis-related proteins. The cherry thaumatin-like protein does not have a sweet taste, and no antifungal activity was seen in preliminary assays. Expression of the protein appears to be regulated at the gene level, with mRNA levels at their highest in the ripe fruit.
一种29千道尔顿的多肽是成熟樱桃果实（欧洲甜樱桃）中含量最丰富的可溶性蛋白质；随着果实从黄色变为红色，在成熟开始时积累。这种蛋白质从成熟樱桃中提取，并通过尺寸排阻色谱和离子交换色谱进行纯化。用针对纯化蛋白质的抗体筛选成熟樱桃的cDNA文库。许多重组噬菌斑与抗体呈阳性反应；代表性克隆的DNA序列编码一个由245个氨基酸残基组成的多肽。显示有一个信号肽，预测的成熟蛋白在大小（通过质谱法测定为23.3千道尔顿）和等电点（4.2）方面与纯化蛋白相对应。对已知蛋白质序列的搜索显示，该多肽与病程相关蛋白的thaumatin家族有很强的相似性。樱桃类thaumatin蛋白没有甜味，在初步试验中也未观察到抗真菌活性。该蛋白的表达似乎在基因水平上受到调控，成熟果实中的mRNA水平最高。
