Matsuura Keiichi, Miyagawa Isao, Kobayashi Masaru, Ohta Daisaku, Matoh Toru
Laboratory of Plant Nutrition, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan.
J Exp Bot. 2003 Jul;54(388):1785-7. doi: 10.1093/jxb/erg181. Epub 2003 May 13.
The molecular characterization of two isoforms of 3-deoxy-d-manno-oct-2-ulosonate (KDO) -8-phosphate synthase (AtkdsA1 and AtkdsA2) from Arabidopsis is reported here. First, by isolating a full-length cDNA for AtkdsA1, it was confirmed that the deduced primary structures of AtkdsA1 and AtkdsA2 proteins were 93% identical. Functional expression and purification studies demonstrated the efficient catalytic activity of the AtkdsA1 enzyme to produce KDO-8-phosphate from phosphoenolpyruvate and d-arabinose-5-phosphate. RT-PCR and RNA-gel blot analysis revealed different expression profiles for both genes; the AtkdsA1 gene was predominantly expressed in the shoots, while the AtkdsA2 transcript accumulated to a higher level in the roots, implicating differential roles of these isoforms in planta.
本文报道了拟南芥中3-脱氧-D-甘露-辛-2-酮酸（KDO）-8-磷酸合酶的两种同工型（AtkdsA1和AtkdsA2）的分子特征。首先，通过分离AtkdsA1的全长cDNA，证实AtkdsA1和AtkdsA2蛋白的推导一级结构有93%的同一性。功能表达和纯化研究表明AtkdsA1酶能有效地催化磷酸烯醇丙酮酸和D-阿拉伯糖-5-磷酸生成KDO-8-磷酸。RT-PCR和RNA凝胶印迹分析揭示了这两个基因不同的表达谱；AtkdsA1基因主要在地上部分表达，而AtkdsA2转录本在根中积累到更高水平，这表明这些同工型在植物中有不同的作用。
