Subtle Control of Carbon Chain Length in Polyunsaturated Fatty Acid Synthases
Subtle Control of Carbon Chain Length in Polyunsaturated Fatty Acid Synthases
复制标题
多不饱和脂肪酸合成酶中碳链长度的微妙控制
DOI：
10.1021/acschembio.9b00803
复制
发表时间：
2019
影响因子：
4
通讯作者：
Dairi Tohru
中科院分区：
文献类型：
--
作者：
Naka Mai;Ikeuchi Kenshin;Hayashi Shohei;Satoh Yasuharu;Ogasawara Yasushi;Dairi Tohru
一些海洋细菌通过由四个亚基（A-D）组成的酶复合物合成二十二碳六烯酸（DHA; C22）和二十碳五烯酸（EPA; C20）。我们最近发现，β-酮脂酰合酶（KSC）/链长因子（CLF）样结构域的DHA合酶的“C”亚基催化的最后一个延伸步骤（C20至C22），即使他们的氨基酸序列是非常相似的EPA合酶。为了研究控制产物链长度的氨基酸残基，将DHA合酶中KSC/CLF样结构域中的保守残基用相应的EPA合酶残基替换。在12个突变体中，两个CLF样结构域突变的基因在与dha-ABDin大肠杆菌共表达时完全失去DHA生产力并产生微量EPA，而当与thepa-ABD共表达时，它们产生相同量的EPA asepa-ABCD。这些结果表明，产物谱由几个氨基酸残基微妙地控制。
Some marine bacteria synthesize docosahexaenoic acid (DHA; C22) and eicosapentaenoic acid (EPA; C20) by enzyme complexes composed of four subunits (A–D). We recently revealed that β-ketoacyl synthase (KSC)/chain length factor (CLF)-like domains in the “C” subunit of DHA synthase catalyzed the last elongation step (C20to C22) even though their amino acid sequences are very similar to those of EPA synthase. To investigate the amino acid residues controlling the product chain length, conserved residues in the KSC/CLF-like domains in DHA synthase were replaced with corresponding EPA synthase residues. Among 12 mutants, two CLF-like domain-mutated genes completely lost DHA productivity and produced trace amounts of EPA when coexpressed withdha-ABDinEscherichia coli, whereas when coexpressed withepa-ABD, they produced the same amounts of EPA asepa-ABCD. These results suggest that the product profiles were subtly controlled by several amino acid residues.