来自游动放线菌SE 50/110的阿卡波糖生物合成酶AcbO是一种2-表-5-表-戊糖素-7-磷酸2-表异构酶。

The acarbose-biosynthetic enzyme AcbO from Actinoplanes sp. SE 50/110 is a 2-epi-5-epi-valiolone-7-phosphate 2-epimerase.

作者信息

Zhang Chang-Sheng, Podeschwa Michael, Altenbach Hans-Josef, Piepersberg Wolfgang, Wehmeier Udo F

机构信息

Institute of Chemical Microbiology, Bergische University, Gauss-Str 20, D-42097 Wuppertal, Germany.

出版信息

FEBS Lett. 2003 Apr 10;540(1-3):47-52. doi: 10.1016/s0014-5793(03)00221-7.

DOI:10.1016/s0014-5793(03)00221-7

PMID:12681481

Abstract

The C7-cyclitol 2-epi-5-epi-valiolone is the first precursor of the cyclitol moiety of the alpha-glucosidase inhibitor acarbose in Actinoplanes sp. SE50. The 2-epi-5-epi-valiolone becomes phosphorylated at C7 by the ATP dependent kinase AcbM prior to the next modifications. Preliminary data gave evidences that the AcbO protein could catalyse the first modification step of 2-epi-5-epi-valiolone-7-phosphate. Therefore, the AcbO protein, the encoding gene of which is also part of the acbKMLNOC operon, was overproduced and purified. Indeed the purified protein catalysed the 2-epimerisation of 2-epi-5-epi-valiolone-7-phosphate. The chemical structure of the purified reaction product was proven by nuclear magnetic resonance spectroscopy to be 5-epi-valiolone-7-phosphate.

摘要

在游动放线菌SE50中，C7-环醇2-表-5-表-缬氨霉素是α-葡萄糖苷酶抑制剂阿卡波糖中环醇部分的首个前体。在进行下一步修饰之前，2-表-5-表-缬氨霉素通过依赖ATP的激酶AcbM在C7位发生磷酸化。初步数据表明，AcbO蛋白可催化2-表-5-表-缬氨霉素-7-磷酸的首个修饰步骤。因此，编码基因也是acbKMLNOC操纵子一部分的AcbO蛋白被过量表达并纯化。事实上，纯化后的蛋白催化了2-表-5-表-缬氨霉素-7-磷酸的2-差向异构化反应。通过核磁共振光谱法证实，纯化后反应产物的化学结构为5-表-缬氨霉素-7-磷酸。