Identification of a thiamin-dependent synthase in Escherichia coli required for the formation of the 1-deoxy-D-xylulose 5-phosphate precursor to isoprenoids, thiamin, and pyridoxol
Identification of a thiamin-dependent synthase in Escherichia coli required for the formation of the 1-deoxy-D-xylulose 5-phosphate precursor to isoprenoids, thiamin, and pyridoxol
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DOI：
10.1073/pnas.94.24.12857
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发表时间：
1997-11-25
影响因子：
11.1
通讯作者：
Sahm, H
中科院分区：
文献类型：
--
作者：
Sprenger, GA;Schorken, U;Sahm, H
在大肠杆菌中，1-脱氧-D-木糖(或其5-磷酸，DXP)是异戊烯基二磷酸的生物合成前体[Broers，S.T.J.(1994)学位论文(eidgenossische Technische Hochschule，苏黎世)]，硫胺素和吡哆醇[Himmeldirk，K.，Kennedy，I.A.，Hill，R.E.，Sayer，B.G.&Spenser，I.D.(1996)Chem]。交警。1187-1188]，我们发现在大肠杆菌染色体图谱上有一个9分钟的开放阅读框编码一种酶(脱氧果糖-5-磷酸合成酶，DXP合成酶)，该酶催化丙酮酸的C原子2和3与3-磷酸甘油醛发生依赖于硫胺素的酰环素缩合反应生成DXP。我们克隆并高效表达了该基因(DXS)，该酶纯化了17倍，比活力为0.85单位/毫克蛋白质。DXP合成酶催化的反应只产生DXP，其结构经H-1和P-31核磁共振谱表征虽然大肠杆菌的DXP合成酶与转酮醇酶和丙酮酸脱氢酶的E1亚基序列相似，但它是一个不同的蛋白质家族的成员，推测的DXP合成酶序列似乎在细菌和植物叶绿体中广泛存在。
In Escherichia coli, 1-deoxy-D-xylulose (or its 5-phosphate, DXP) is the biosynthetic precursor to isopentenyl diphosphate [Broers, S. T. J. (1994) Dissertation (Eidgenossische Technische Hochschule, Zurich)], thiamin, and pyridoxol [Himmeldirk, K., Kennedy, I. A., Hill, R. E., Sayer, B. G. & Spenser, I. D. (1996) Chem. Commun. 1187-1188], Here we show that an open reading frame at 9 min on the chromosomal map of E. coli encodes an enzyme (deoxyxylulose-5-phosphate synthase, DXP synthase) that catalyzes a thiamin diphosphate-dependent acyloin condensation reaction between C atoms 2 and 3 of pyruvate and glyceraldehyde 3-phosphate to yield DXP, We have cloned and overexpressed the gene (dxs), and the enzyme was purified 17-fold to a specific activity of 0.85 unit/mg of protein, The reaction catalyzed by DXP synthase yielded exclusively DXP, which was characterized by H-1 and P-31 NMR spectroscopy, Although DXP synthase of E. coli shows sequence similarity to both transketolases and the E1 subunit of pyruvate dehydrogenase, it is a member of a distinct protein family, and putative DXP synthase sequences appear to be widespread in bacteria and plant chloroplasts.