Biosynthesis pathway of ADP-L-glycero-β-D-manno-heptose in Escherichia coli
Biosynthesis pathway of ADP-L-glycero-β-D-manno-heptose in Escherichia coli
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DOI：
10.1128/jb.184.2.363-369.2002
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发表时间：
2002-01-01
影响因子：
3.2
通讯作者：
Messner, P
中科院分区：
文献类型：
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作者：
Kneidinger, B;Marolda, C;Messner, P
涉及内核脂多糖（LPS）的ADP-L-甘油-β-D-甘露庚糖（ADP-L-P-D-庚糖）前体的生物合成的步骤尚未完全阐明。在这项工作中，我们已经纯化了参与催化ADP-D-β-D-庚糖合成的中间步骤的酶，并通过高效阴离子交换色谱法对反应产物进行了生物化学表征。我们还构建了一个新的基因，gmhB（以前的yaeD），这导致在一个改变的LPS核心的形成删除。该突变证实GmhB蛋白是ADP-D-β-D-庚糖形成所需的。我们的研究结果表明，ADP-D-β-D-庚糖在大肠杆菌中的合成需要三种蛋白质，GmhA（景天庚酮糖7-磷酸异构酶），HldE（双功能D-β-D-庚糖7-磷酸激酶/D-β-D-庚糖1-磷酸腺苷酰转移酶），和GmhB（D，D-庚糖1，7-二磷酸酶），以及ATP和酮糖磷酸前体景天庚酮糖7-磷酸。先前表征的差向异构酶，以前称为WaaD（Rfaf），现在更名为HIdD，完成形成用于组装内核LPS的ADP-L-β-D-庚糖前体的途径。
The steps involved in the biosynthesis of the ADP-L-glycero-P-D-manno-heptose (ADP-L-P-D-heptose) precursor of the inner core lipopolysaccharide (LPS) have not been completely elucidated. In this work, we have purified the enzymes involved in catalyzing the intermediate steps leading to the synthesis of ADP-D-beta -D-heptose and have biochemically characterized the reaction products by high-performance anion-exchange chromatography. We have also constructed a deletion in a novel gene, gmhB (formerly yaeD), which results in the formation of an altered LPS core. This mutation confirms that the GmhB protein is required for the formation of ADP-D-beta -D-heptose. Our results demonstrate that the synthesis of ADP-D-beta -D-heptose in Escherichia coli requires three proteins, GmhA (sedoheptulose 7-phosphate isomerase), HldE (bifunctional D-beta -D-heptose 7-phosphate kinase/D-beta -D-heptose 1-phosphate adenylyltransferase), and GmhB (D,D-heptose 1,7-bisphosphate phosphatase), as well as ATP and the ketose phosphate precursor sedoheptulose 7-phosphate. A previously characterized epimerase, formerly named WaaD (Rfaf)) and now renamed HIdD, completes the pathway to form the ADP-L-beta -D-heptose precursor utilized in the assembly of inner core LPS.