Maras B, Ippoliti R, De Luca E, Lendaro E, Bellelli A, Barra D, Bossa F, Brunori M
Dipartimento di Scienze Biochimiche, Università La Sapienza, Roma, Italy.
Biochem Int. 1990 Aug;21(5):831-8.
The complete primary structure of saporin SO-6, a ribosome-inactivating protein extracted from Saponaria officinalis seeds, has been determined. The sequence was reconstructed following purification and analysis of peptides obtained after digestion of the protein with different proteolytic agents. The protein is composed of 253 amino acids, corresponding to a molecular weight of 28,621 Da. Comparison of the primary structure of SO-6 with the sequence deduced from cDNA, shows amino acid substitutions in 11 positions, suggesting a tissue-related genetic variability. When the sequence of saporin is compared to those of two related proteins, ricin A chain and trichosanthin, a low degree of similarity (12%) is found; nevertheless some considerations about structure-function relationships and evolution of RIPs are possible.
已确定从肥皂草种子中提取的核糖体失活蛋白皂草素SO-6的完整一级结构。在用不同蛋白酶消化该蛋白后获得的肽段经纯化和分析后，重建了其序列。该蛋白由253个氨基酸组成，分子量为28,621道尔顿。将SO-6的一级结构与从cDNA推导的序列进行比较，发现在11个位置存在氨基酸替换，这表明存在与组织相关的遗传变异性。当将皂草素的序列与两种相关蛋白蓖麻毒素A链和天花粉蛋白的序列进行比较时，发现相似度较低（12%）；然而，关于核糖体失活蛋白的结构-功能关系和进化仍有一些可探讨之处。
