Dure L
Department of Biochemistry, University of Georgia, Athens 30602.
Plant J. 1993 Mar;3(3):363-9. doi: 10.1046/j.1365-313x.1993.t01-19-00999.x.
Among the proteins that accumulate as plant seeds desiccate are several protein families that are composed principally of a tandemly repeated 11-mer amino acid motif. Proteins containing the same motif accumulate in the desiccating leaves of a desiccation-tolerant plant species. This motif is characterized by apolar residues in positions 1, 2, 5 and 9, and charged or amide residues in positions 3, 6, 7, 8 and 11. An alpha helical arrangement of the 11-mer repeating unit gives an amphiphilic helix whose hydrophobic stripe twists in a right-handed fashion around the helix. Should these proteins dimerize via binding of their hydrophobic faces, a right-handed coiled coil would be formed. Such a structure has not previously been observed. A conceivable function for these proteins in ion sequestration in the desiccated state is proposed.
在植物种子脱水时积累的蛋白质中，有几个蛋白质家族，它们主要由一个串联重复的11聚体氨基酸基序组成。含有相同基序的蛋白质在一种耐脱水植物物种的脱水叶片中积累。该基序的特征是在第1、2、5和9位为非极性残基，在第3、6、7、8和11位为带电荷或酰胺残基。11聚体重复单元的α螺旋排列形成一个两亲性螺旋，其疏水条纹以右手方式围绕螺旋扭曲。如果这些蛋白质通过其疏水表面的结合而二聚化，将形成一个右手卷曲螺旋。这种结构以前尚未被观察到。有人提出了这些蛋白质在脱水状态下离子螯合中的一种可能功能。
