Biosynthetic Intermediates of the Tetradehydro Cyclic Dipeptide Albonoursin Produced by Streptomyces albulus KO-23.
作者:HIROSHI KANZAKI、SATOHIRO YANAGISAWA、TERUHIKO NITODA
DOI:10.7164/antibiotics.53.1257
日期:——
The cell-free extract of an albonoursin-producing strain Streptomyces albulus KO-23 catalyzes the conversion of cyclo(L-Leu-L-Phe) (1) to albonoursin (2). At the early stage of this conversion, two compounds were newly formed prior to albonoursin synthesis in the reaction mixture. These compounds were isolated and identified as (Z)-3-benzylidene-6-isobutyl-2, 5-piperazinedione (4) and (Z)-3-benzyl-6-isobutylidene-2, 5-piperazineclione (3). The cell-free extract also catalyzed the conversion of compound 3 or 4 to albonoursin. From these results, albonoursin was found to be biosynthesized via these compounds from cyclo(L-Leu-L-Phe). These didehydro diketopiperazines exhibited no inhibitory activity toward the first cleavage of sea urchin embryo in contrast to the higher cytotoxicity for albonoursin, indicating that dehydrogenation at α, β-positions of both amino acid residues in diketopiperazines is required for cytotoxicity.
一株产阿尔博诺辛的链霉菌Streptomyces albulus KO-23的无细胞提取物催化了环状(L-Leu-L-Phe) (1) 转化为阿尔博诺辛 (2)。在该转化的早期阶段,反应体系中新形成了两个化合物,这两个化合物被分离并鉴定为(Z)-3-苄叉-6-异丁基-2, 5-哌嗪二酮 (4)和(Z)-3-苄-6-异丁烯基-2, 5-哌嗪二酮 (3)。无细胞提取物还催化了化合物3或4转化为阿尔博诺辛。从这些结果来看,阿尔博诺辛的生物合成是通过这些化合物由环状(L-Leu-L-Phe)转化而来的。这些二去氢二酮哌嗪对海胆胚胎的第一次裂变没有抑制活性,而阿尔博诺辛则具有更高的细胞毒性,表明在二酮哌嗪中α、β位的氨基酸残基去氢化是细胞毒性的必要条件。