Teeter M M, Mazer J A, L'Italien J J
Biochemistry. 1981 Sep 15;20(19):5437-43. doi: 10.1021/bi00522a013.
Crambin, a hydrophobic plant seed protein, consists of a single chain of 46 amino acids with a calculated molecular weight of 4720. The primary structure was determined by using solid-phase sequencing techniques and was confirmed through X-ray crystallographic analysis of the protein at 1.5-A resolution [Hendrickson, W. A., & Teeter, M. M. (1981) Nature (London) 290, 107-112]. High-performance liquid chromatographic separation of the proteolytic fragments from crambin led to the identification of two sites of microheterogeneity. The three disulfide bonds were located at positions 3-40, 4-32, and 16-26 from the crystallographic data. Comparison of the primary structure with known sequences revealed that crambin is homologous with the plant toxins purothionin and viscotoxin. Methods to estimate protein secondary structure were applied and found to predict all of crambin's structure except its amphiphilic helix.
胰凝乳蛋白酶抑制剂，一种疏水性植物种子蛋白，由一条46个氨基酸的单链组成，计算分子量为4720。其一级结构通过固相测序技术确定，并通过对该蛋白进行1.5埃分辨率的X射线晶体学分析得到证实[亨德里克森，W. A.，& 蒂特，M. M.（1981年）《自然》（伦敦）290，107 - 112]。通过高效液相色谱对胰凝乳蛋白酶抑制剂的蛋白水解片段进行分离，从而确定了两个微异质性位点。根据晶体学数据，三个二硫键分别位于第3 - 40位、第4 - 32位和第16 - 26位。将其一级结构与已知序列进行比较，发现胰凝乳蛋白酶抑制剂与植物毒素硫堇和蓖麻毒素具有同源性。应用了估计蛋白质二级结构的方法，发现这些方法能预测胰凝乳蛋白酶抑制剂除两亲性螺旋之外的所有结构。
