Bashir M E, Hubatsch I, Leinenbach H P, Zeppezauer M, Panzani R C, Hussein I H
University of Saarland, Saarbrücken, Germany.
Int Arch Allergy Immunol. 1998 Jan;115(1):73-82. doi: 10.1159/000023833.
The 2S albumin storage protein of Ricinus communis consists of the two heterodimeric proteins Ric c 1 and Ric c 3 each of which is composed of a small and a large subunit linked together by disulphide bridges. The complete primary structures of both heterodimeric proteins were determined by enzymatic degradation and automated Edman degradation. The sequences of all four chains correspond to the known cDNA sequence of the gene of a presumed precursor molecule and to the previously determined partial sequences for Ric c 1 and Ric c 3. In addition, few differences in amino acid positions were found which seem to be related to different varieties of R. communis. Sequence comparisons with 2S albumin from other plant genera revealed high degrees of homology and support the view of a common genetic origin of this protein family. Ric c 1 and Ric c 3 which have 11,212 and 12,032 daltons, respectively, share a similar molecular size, biological function and allergenicity with the 2S albumins from Brassica juncea (Braj 1E) and Sinapis alba L (Sin a 1). Ric c 1 and Ric c 3 may be classified as isoallergens if, additionally, the high degree of similarity in the position of polar residues is taken into account.
蓖麻的2S白蛋白储存蛋白由两种异源二聚体蛋白Ric c 1和Ric c 3组成，每种蛋白均由一个小亚基和一个大亚基通过二硫键连接在一起。通过酶促降解和自动Edman降解确定了这两种异源二聚体蛋白的完整一级结构。所有四条链的序列与推测的前体分子基因的已知cDNA序列以及先前确定的Ric c 1和Ric c 3的部分序列一致。此外，发现氨基酸位置上有一些差异，这些差异似乎与蓖麻的不同品种有关。与其他植物属的2S白蛋白进行序列比较，发现高度同源，支持了这个蛋白家族有共同遗传起源的观点。分别具有11,212和12,032道尔顿的Ric c 1和Ric c 3与来自芥菜（Braj 1E）和白芥（Sin a 1）的2S白蛋白具有相似的分子大小、生物学功能和致敏性。此外，如果考虑到极性残基位置的高度相似性，Ric c 1和Ric c 3可被归类为异源过敏原。
