Kim Jin-Yong, Suh Joo-Won, Kang Suk-Ho, Phan Thi Huyen, Park Si-Hyung, Kwon Hyung-Jin
Department of Biological Science, Division of Bioscience and Bioinformatics, Myongji University, Yongin 449-728, Republic of Korea.
Biochem Biophys Res Commun. 2008 Aug 8;372(4):730-4. doi: 10.1016/j.bbrc.2008.05.133. Epub 2008 Jun 3.
A gene inactivation study was performed on gntE, a member of the gentamicin biosynthetic gene cluster in Micromonospora echinospora. Computer-aided homology analysis predicts a methyltransferase-related cobalamin-binding domain and a radical S-adenosylmethionine domain in GntE. It is also found that there is no gntE homolog within other aminoglycoside biosynthetic gene clusters. Inactivation of gntE was achieved in both M. echinospora ATCC 15835 and a gentamicin high-producer GMC106. High-performance liquid chromatographic analysis, coupled with mass spectrometry, revealed that gntE mutants accumulated gentamicin A2 and its derivative with a methyl group installed on the glucoamine moiety. This result substantiated that GntE participates in the first step of pseudotrisaccharide modifications in gentamicin biosynthesis, though the catalytic nature of this unusual oxidoreductase/methyltransferase candidate is not resolved. The present gene inactivation study also demonstrates that targeted genetic engineering can be applied to produce specific gentamicin structures and potentially new gentamicin derivatives in M. echinospora.
对棘孢小单孢菌中庆大霉素生物合成基因簇的成员gntE进行了基因失活研究。计算机辅助同源性分析预测GntE中存在一个与甲基转移酶相关的钴胺素结合结构域和一个自由基S-腺苷甲硫氨酸结构域。还发现其他氨基糖苷生物合成基因簇中不存在gntE同源物。在棘孢小单孢菌ATCC 15835和庆大霉素高产菌株GMC106中均实现了gntE的失活。高效液相色谱分析结合质谱表明，gntE突变体积累了庆大霉素A2及其在葡糖胺部分带有甲基的衍生物。这一结果证实了GntE参与庆大霉素生物合成中假三糖修饰的第一步，尽管这种不寻常的氧化还原酶/甲基转移酶候选物的催化性质尚未明确。目前的基因失活研究还表明，靶向基因工程可用于在棘孢小单孢菌中产生特定的庆大霉素结构和潜在的新庆大霉素衍生物。
