Rapid and flexible synthesis of 1-deoxy-<scp>d</scp>-xylulose-5-phosphate, the substrate for 1-deoxy-<scp>d</scp>-xylulose-5-phosphate reductoisomerase
作者:Russell J. Cox、Ana de Andrés-Gómez、Christopher R. A. Godfrey
DOI:10.1039/b307314a
日期:——
1-Deoxy-D-xylulose-5-phosphate (DXP) is a key intermediate in the non-mevalonate pathway to terpenoids in bacteria, and it is the substrate for the enzyme 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXP-R). In order to study the mechanism of DXP-R, we required a flexible synthesis of the substrate which would allow the incorporation of isotopic labels, and the variation of the two stereocentres. Thus 1,4-dihydroxypent-2-yne was selectively reduced to give the E-olefin, and selective phosphorylation of the primary alcohol followed by oxidation of the secondary alcohol gave a substrate suitable for dihydroxylation. Dihydroxylation using stoichiometric OsO4 in the presence of chiral ligands gave protected DXP in high ee. Final hydrogenolysis gave DXP in quantitative yield and high purity. DXP-R was produced by rapid cloning of the dxr gene from Escherichia coli through controlled expression and ion exchange chromatography. The synthetic DXP was fully active in enzyme assays catalysed by recombinant DXP-R.
1-Deoxy-D-xylulose-5-phosphate (DXP)是细菌中萜类化合物非甲羟戊酸途径中的一个关键中间体,它是 1-Deoxy-D-xylulose-5-phosphate reductoisomerase (DXP-R)酶的底物。为了研究 DXP-R 的机理,我们需要一种灵活的底物合成方法,以便能够加入同位素标记和改变两个立体中心。因此,我们选择性地还原了 1,4-二羟基戊-2-炔,得到了 E-烯烃,并选择性地磷酸化了伯醇,然后氧化了仲醇,得到了适合二羟基化的底物。在手性配体存在的情况下,使用定量的 OsO4 进行二羟基化反应,可以得到高ee值的受保护 DXP。最后氢解得到的 DXP 产率高、纯度高。通过控制表达和离子交换色谱法,从大肠杆菌中快速克隆出了 dxr 基因,从而制得了 DXP-R。合成的 DXP 在重组 DXP-R 催化的酶测定中具有完全活性。