Brabetz W, Brade H
Division of Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Germany.
Eur J Biochem. 1997 Feb 15;244(1):66-73. doi: 10.1111/j.1432-1033.1997.00066.x.
The kdsA gene encoding 3-deoxy-D-manno-2-octulosonate-8-phosphate (Kdo-8-P) synthase of Chlamydia psittaci 6BC was cloned by complementing the temperature-sensitive kdsA mutant Salmonella enterica serovar Typhimurium AG701i50. The sequence analysis of a recombinant DNA fragment revealed an open reading frame of 807 nucleotides which codes for a polypeptide of 269 amino acids with a high degree of similarity to known KdsA proteins. In addition, alignments of Kdo-8-P synthases with bacterial and fungal 3-deoxy-D-arabino-2-heptulosonate-7-phosphate (Dha-7-P) synthases suggested that both classes of enzymes are structurally related and may belong to a family of 2-keto-3-deoxy-aldonic acid synthases. The chlamydial protein was overexpressed and functionally characterized in vitro to synthesize Kdo-8-P from D-arabinose 5-phosphate and phosphoenolpyruvate. A chlamydial DNA region upstream of the gene exhibiting similarities to the consensus sequence of sigma 70 promoters of Escherichia coli was responsible for the heterologous expression of kdsA.
通过对温度敏感型kdsA突变体肠炎沙门氏菌鼠伤寒血清型AG701i50进行互补，克隆了编码鹦鹉热衣原体6BC 3-脱氧-D-甘露-2-辛酮酸-8-磷酸（Kdo-8-P）合酶的kdsA基因。对一个重组DNA片段的序列分析揭示了一个807个核苷酸的开放阅读框，其编码一个269个氨基酸的多肽，与已知的KdsA蛋白具有高度相似性。此外，Kdo-8-P合酶与细菌和真菌的3-脱氧-D-阿拉伯-2-庚酮酸-7-磷酸（Dha-7-P）合酶的比对表明，这两类酶在结构上相关，可能属于2-酮-3-脱氧-醛糖酸合酶家族。衣原体蛋白在体外进行了过量表达和功能表征，以从5-磷酸-D-阿拉伯糖和磷酸烯醇丙酮酸合成Kdo-8-P。该基因上游的一个衣原体DNA区域与大肠杆菌σ70启动子的共有序列相似，负责kdsA的异源表达。
