Interdisciplinary Programs of Bioengineering, Seoul National University, Seoul 151-742, Republic of Korea.
Appl Environ Microbiol. 2011 Jul;77(14):4912-23. doi: 10.1128/AEM.02527-10. Epub 2011 May 20.
Doxorubicin, one of the most widely used anticancer drugs, is composed of a tetracyclic polyketide aglycone and l-daunosamine as a deoxysugar moiety, which acts as an important determinant of its biological activity. This is exemplified by the fewer side effects of semisynthetic epirubicin (4'-epi-doxorubicin). An efficient combinatorial biosynthetic system that can convert the exogenous aglycone ε-rhodomycinone into diverse glycosylated derivatives of doxorubicin or its biosynthetic intermediates, rhodomycin D and daunorubicin, was developed through the use of Streptomyces venezuelae mutants carrying plasmids that direct the biosynthesis of different nucleotide deoxysugars and their transfer onto aglycone, as well as the postglycosylation modifications. This system improved epirubicin production from ε-rhodomycinone by selecting a substrate flexible glycosyltransferase, AknS, which was able to transfer the unnatural sugar donors and a TDP-4-ketohexose reductase, AvrE, which efficiently supported the biosynthesis of TDP-4-epi-l-daunosamine. Furthermore, a range of doxorubicin analogs containing diverse deoxysugar moieties, seven of which are novel rhodomycin D derivatives, were generated. This provides new insights into the functions of deoxysugar biosynthetic enzymes and demonstrates the potential of the S. venezuelae-based combinatorial biosynthetic system as a simple biological tool for modifying structurally complex sugar moieties attached to anthracyclines as an alternative to chemical syntheses for improving anticancer agents.
多柔比星是最广泛使用的抗癌药物之一，由四环多酮糖苷配基和 l-去氧氨基葡萄糖组成，它是其生物活性的重要决定因素。这方面的一个例子是半合成表柔比星（4'-表多柔比星）的副作用较少。通过使用携带指导不同核苷酸去氧糖及其与糖苷配基结合以及后续糖基化修饰的生物合成质粒的委内瑞拉链霉菌突变体，开发了一种有效的组合生物合成系统，该系统可将外源糖苷配基 ε-红比霉素酮转化为多柔比星或其生物合成中间体柔红霉素 D 和柔红霉素的各种糖基化衍生物。该系统通过选择能够转移非天然糖供体的底物灵活糖基转移酶 AknS 和能够有效支持 TDP-4-表-l-去氧氨基葡萄糖生物合成的 TDP-4-酮己糖还原酶 AvrE，提高了从 ε-红比霉素酮生产表柔比星的产量。此外，还生成了一系列含有不同去氧糖部分的多柔比星类似物，其中有 7 种是新型柔红霉素衍生物。这为去氧糖生物合成酶的功能提供了新的见解，并展示了基于委内瑞拉链霉菌的组合生物合成系统作为一种简单的生物学工具的潜力，可用于修饰与蒽环类抗生素结合的结构复杂的糖部分，作为提高抗癌药物的替代化学合成方法。
