Cloning and characterization of a gene from Escherichia coli encoding a transketolase-like enzyme that catalyzes the synthesis of D-1-deoxyxylulose 5-phosphate, a common precursor for isoprenoid, thiamin, and pyridoxol biosynthesis
Cloning and characterization of a gene from Escherichia coli encoding a transketolase-like enzyme that catalyzes the synthesis of D-1-deoxyxylulose 5-phosphate, a common precursor for isoprenoid, thiamin, and pyridoxol biosynthesis
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DOI：
10.1073/pnas.95.5.2105
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发表时间：
1998-03-03
影响因子：
11.1
通讯作者：
Boronat, A
中科院分区：
文献类型：
--
作者：
Lois, LM;Campos, N;Boronat, A
多年来，所有类异戊二烯类化合物的共同前体二磷酸异戊烯酯都是通过众所周知的醋酸/甲戊酸途径合成的，然而，最近的研究表明，包括大肠杆菌在内的一些细菌使用不依赖于甲戊酸的途径合成二磷酸异戊烯酯，这种替代途径在绿藻和高等植物中也有报道。该途径的第一个反应是由丙酮酸衍生的（羟乙基）硫胺素与d -甘油醛3-磷酸的C1醛基团缩合生成d -1-脱氧羟糖5-磷酸，在大肠杆菌中，d -1-脱氧羟糖5-磷酸也是生物合成硫胺素和吡哆醇的前体。在这里，我们报道了大肠杆菌中编码d -1-脱氧羟糖5-磷酸合成酶的基因dxs的分子克隆和表征。dxs基因被鉴定为包含ispA的操纵子的一部分，ispA是编码法尼基二磷酸合成酶的基因，d -1-脱氧葡糖-5-磷酸合成酶属于一个在进化中高度保守的转酮醇酶样蛋白家族。
For many years it was accepted that isopentenyl diphosphate, the common precursor of all isoprenoids, was synthesized through the well known acetate/mevalonate pathway, However, recent studies have shown that some bacteria, including Escherichia coli, use a mevalonate-independent pathway for the synthesis of isopentenyl diphosphate, The occurrence of this alternative pathway has also been reported in green algae and higher plants. The first reaction of this pathway consists of the condensation of (hydroxyethyl)thiamin derived from pyruvate with the C1 aldehyde group of D-glyceraldehyde 3-phosphate to yield D-1-deoxyxylulose 5-phosphate, In E. coli, D-1-deoxyxylulose 5-phosphate is also a precursor for the biosynthesis of thiamin and pyridoxol, Here we report the molecular cloning and characterization of a gene from E. coli, designated dxs, that encodes D-1-deoxyxylulose-5-phosphate synthase, The dxs gene was identified as part of an operon that also contains ispA, the gene that encodes farnesyl-diphosphate synthase, D-1-Deoxyxylulose-5-phosphate synthase belongs to a family of transketolase-like proteins that are highly conserved in evolution.