Zhao Zongbao, Hong Lin, Liu Hung-wen
Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, USA.
J Am Chem Soc. 2005 Jun 1;127(21):7692-3. doi: 10.1021/ja042702k.
d-Forosamine is a 4-N,N-(dimethylamino)-2,3,4,6-tetradeoxy-alpha-d-threo-hexopyranose found in spinosyn produced by Saccharopolyspora spinosa. Studies of spinosyn biosynthesis in S. spinosa led to the isolation of the entire biosynthetic gene cluster. Heterologous expression of spnR, one putative gene in forosamine biosynthesis, in E. coli and purification of the SpnR protein identified it as an aminotransferase catalyzing the conversion of the 4-keto-2,3,6-trideoxy sugar intermediate to the corresponding 4-amino sugar product. Identification of SpnR function relied on the use of a stable TMP-phosphonate sugar in place of TDP-sugar substrate to determine the function of SpnR. This strategy may find general applicability for designing probes to study enzymes which catalyze the transformation of labile deoxysugar intermediates.
d-福乐胺是一种4-N,N-（二甲基氨基）-2,3,4,6-四脱氧-α-d-苏式己吡喃糖，存在于多刺糖多孢菌产生的多杀菌素中。对多刺糖多孢菌中多杀菌素生物合成的研究导致了整个生物合成基因簇的分离。福乐胺生物合成中一个推定基因spnR在大肠杆菌中的异源表达以及SpnR蛋白的纯化表明它是一种转氨酶，催化4-酮-2,3,6-三脱氧糖中间体转化为相应的4-氨基糖产物。SpnR功能的鉴定依赖于使用稳定的TMP-膦酸酯糖代替TDP-糖底物来确定SpnR的功能。这种策略可能在设计探针以研究催化不稳定脱氧糖中间体转化的酶方面具有普遍适用性。
