BIOSYNTHESIS OF PHYTOSIDEROPHORES, MUGINEIC ACIDS, ASSOCIATED WITH METHIONINE CYCLING
BIOSYNTHESIS OF PHYTOSIDEROPHORES, MUGINEIC ACIDS, ASSOCIATED WITH METHIONINE CYCLING
复制标题
DOI：
10.1074/jbc.270.28.16549
复制
发表时间：
1995-07-14
影响因子：
4.8
通讯作者：
NOMOTO, K
中科院分区：
文献类型：
--
作者：
MA, JF;SHINADA, T;NOMOTO, K
利用标记实验和结构分析研究了小麦根中关键的植物铁载体2 '-脱氧麦根酸的生物合成与假定的甲硫氨酸再循环途径的关系。用D-[1-C-13]核糖喂养不会导致2'-脱氧麦根酸的C-13富集，而D-[2-C-13]核糖导致C-13富集在C-4“，-1，D-[5-C-13]核糖分别在2 ′-脱氧mugineic酸的C-1 ′、-4和-1 ″位发生作用。此外，合成了两种同位素标记的蛋氨酸循环途径的中间体，5-[5-H-2（2）]甲硫基核糖和2-[1-C-13]酮基-4-甲硫基丁酸，并研究了它们与2 '-脱氧mugineic酸的结合。用5-[5-H-2（2）]甲基硫代核糖给药后，在2 '-脱氧mugineic酸的C-4、-1'和-1“位上观察到6个氘原子。用2-[1-C-13]酮基-4-甲硫基丁酸进料，得到在C-4 ′、-1和-4 ″位富含C-13的2 ′-脱氧麦根酸。这些结果首次证明了2 '-脱氧mugineic酸的生物合成与甲硫氨酸再循环途径有关。该缔合系统的功能是回收在禾本科植物的根中持续合成麦根酸所需的甲硫氨酸。
The biosynthesis of 2'-deoxymugineic acid, a key phytosiderophore, was examined in association with the putative methionine recycling pathway in the roots of wheat using labeling experiments and structural analysis, Feeding with D-[1-C-13]ribose did not result in C-13 enrichment of 2'-deoxymugineic acid, while D-[2-C-13]ribose resulted in C-13 enrichment at the C-4'', -1, -4' positions, and D-[5-C-13]ribose did in C-1', -4, and -1'' positions of 2'-deoxymugineic acid, respectively. Furthermore, two isotope-labeled intermediates of the methionine recycling pathway, 5-[5-H-2(2)]methylthioribose and 2-[1-C-13]keto-4-methylthiobutyric acid, were synthesized, and their incorporation into 2'-deoxymugineic acids was investigated. Six deuterium atoms at the C-4, -1', and -1'' positions of 2'-deoxymugineic acid were observed after feeding with 5-[5-H-2(2)]methylthioribose. Feeding with 2-[1-C-13]keto-4-methylthiobutyric acid yielded 2'-deoxymugineic acid enriched with C-13 at the C-4', -1, and -4'' positions. These results demonstrated for the first time that the biosynthesis of 2'-deoxymugineic acid is associated with the methionine recycling pathway. This association system functions to recycle methionine required for continued synthesis of mugineic acids in the roots of gramineous plants.