Doi-Katayama Y, Yoon Y J, Choi C Y, Yu T W, Floss H G, Hutchinson C R
School of Pharmacy, University of Wisconsin, Madison 53706, USA.
J Antibiot (Tokyo). 2000 May;53(5):484-95. doi: 10.7164/antibiotics.53.484.
The role of two thioesterase genes in the premature release of polyketide synthase intermediates during rifamycin biosynthesis in the Amycolatopsis mediterranei S699 strain was investigated. Creation of an in-frame deletion in the rifR gene led to a 30 approximately 60% decrease in the production of both rifamycin B by the S699 strain or a series of tetra- to decaketide shunt products of polyketide chain assembly by the rifF strain. Since a similar percentage decrease was seen in both genetic backgrounds, we conclude that the RifR thioesterase 2 is not involved in premature release of the carbon chain assembly intermediates. Similarly, fusion of the Saccharopolyspora erythraea DEBS3 thioesterase I domain to the C-terminus of the RifE PKS subunit did not result in a noticeable increase in the amount of the undecaketide intermediate formed nor in the amounts of the tetra- to decaketide shunt products. Hence, premature release of the carbon chain assembly intermediates is an unusual property of the Rif PKS itself.
研究了地中海拟无枝酸菌S699菌株利福霉素生物合成过程中两个硫酯酶基因在聚酮合酶中间体过早释放中的作用。在rifR基因中创建框内缺失导致S699菌株利福霉素B的产量降低约30%至60%，或rifF菌株聚酮链组装的一系列四至十酮分流产物的产量降低。由于在两种遗传背景下均观察到相似的降低百分比，我们得出结论，RifR硫酯酶2不参与碳链组装中间体的过早释放。同样，将红色糖多孢菌DEBS3硫酯酶I结构域融合到RifE聚酮合酶亚基的C末端，既没有导致十一酮中间体形成量的显著增加，也没有导致四至十酮分流产物量的显著增加。因此，碳链组装中间体的过早释放是Rif聚酮合酶本身的一种不寻常特性。
