The structure of UCH9, which is a novel antitumor agent, was determined by spectroscopic methods. UCH9 consists of an aglycone and five 2, 6-dideoxy sugars (three D-olivoses, one 4-O-methyl-D-olivose and one D-oliose). Four of the five sugars are sequentially connected through a β1→3 linkage (olivose-1→3-4-O-methyl-olivose-1→3-oliose-1→3-olivose). On the basis of the results of spectroscopic analysis, it was found that UCH9 belongs to the aureolic acid family of antibiotics. The structure of UCH9 is unique in that mono- and tetrasaccharide moieties, and a long hydrophobic side chain (sec-butyl group) are attached to the aglycone, while di- and trisaccharide moieties and a methyl or a hydrogen are attached in the case of the known aureolic acid analogs. It is known that aureolic acid analogs form a dimer in the presence of Mg2+. NMR, FAB-MS and atomic absorption analysis revealed that UCH9 isolated from Streptomyces also forms a dimer, containing one equivalent molar Mg2+
UCH9的结构是一种新型抗肿瘤剂,通过光谱方法确定。UCH9由一个非糖部分和五种
2,6-二脱氧糖组成(包括三个D-橄榄糖、一个4-O-
甲基-D-橄榄糖和一个D-橄榄糖)。五种糖中有四种通过β1→3连接依次相连(橄榄糖-1→3-4-O-
甲基-橄榄糖-1→3-橄榄糖-1→3-橄榄糖)。根据光谱分析的结果,发现UCH9属于
金黄色酸类
抗生素。UCH9的结构独特,因为它的非糖部分连接了
单糖和四糖基团,以及一个长的疏
水性侧链(叔丁基),而已知的
金黄色酸类类似物则连接了二糖和三糖基团以及一个
甲基或
氢。已知
金黄色酸类类似物在存在Mg2+的情况下会形成二聚体。NMR、
FAB-MS和原子吸收分析显示,从放线菌中分离的UCH9也形成了一个含有一个当量摩尔的Mg2+的二聚体。