Elaboration of neosamine rings in the biosynthesis of neomycin and butirosin
Elaboration of neosamine rings in the biosynthesis of neomycin and butirosin
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DOI：
10.1002/cbic.200600371
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发表时间：
2007-02-12
期刊：
影响因子：
3.2
通讯作者：
Spencer, Jonathan B.
中科院分区：
文献类型：
--
作者：
Huang, Fanglu;Spiteller, Dieter;Spencer, Jonathan B.
弗拉迪链霉菌 NCIMB 8233 的新霉素基因簇 (neo) 中编码的蛋白质 Neo-11 和 Neo-18 分别被表征为葡萄糖胺基-6'-氧化酶和 6'-氧葡萄糖胺基:L-谷氨酸转氨酶。 Neo-11 和 Neo-18 的联合活性负责在新霉素的生物合成途径中通过 FAD 依赖性脱氢机制以及随后的吡哆醛-5'-磷酸介导的转氨作用将巴罗马胺转化为新胺。 Neo-18 还显示出催化新霉素 C-6''' 处的脱氨作用，因此表明这两种酶在新霉素的两个新糖胺环形成中具有双功能作用。 btrB基因的产物是环状芽孢杆菌中butirosin生物合成基因簇(btr)中neo-18的同源物，表现出与Neo-18相同的活性；这表明布替罗辛和新霉素生物合成中存在相似的反应序列。
The proteins Neo-11 and Neo-18 encoded in the neomycin gene cluster (neo) of Streptomyces fradiae NCIMB 8233 hove been characterized as glucosaminyl-6'-oxidase and 6'-oxoglucosammyi-nyl:L-glutamate aminotransferase, respectively. The joint activity of Neo-11 and Neo-18 is responsible for the conversion of paromamine to neamine in the biosynthetic pathway of neomycin through a mechanism of FAD-dependent dehydrogenation followed by a pyridoxal-5'-phosphate-mediated transamination. Neo-18 is also shown to catalyze deamination at C-6''' of neomycin, thus suggesting bifunctional roles of the two enzymes in the formation of both neosamine rings of neomycin. The product of the btrB gene, a homologue of neo-18 in the butirosin biosynthetic gene cluster (btr) in Bacillus circulans, exhibits the same activity as Neo-18; this indicates that there is a similar reaction sequence in both butirosin and neomycin biosynthesis.