Alteration of a single amino acid changes the substrate specificity of dihydroflavonol 4-reductase
Alteration of a single amino acid changes the substrate specificity of dihydroflavonol 4-reductase
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DOI：
10.1046/j.1365-313x.2001.00962.x
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发表时间：
2001-02-01
期刊：
影响因子：
7.2
通讯作者：
Choi, G
中科院分区：
文献类型：
--
作者：
Johnson, ET;Ryu, S;Choi, G
由于缺乏必需的基因或生物合成酶的底物专一性，许多植物的花色范围变小。矮牵牛不开橙花是因为该物种的二氢黄酮醇4-还原酶(DFR)，一种参与花青素生物合成的酶，低效地减少了二氢山奈酚，二氢山奈酚是橙色天竺葵素型花青素的前体。然而，DFR的底物特异性还没有在分子水平上进行研究。通过分析矮牵牛和非洲菊的嵌合DFR，我们确定了一个决定DFR底物专一性的区域。此外，通过改变这个假定的底物结合区中的一个氨基酸，我们开发了一种DFR酶，它优先还原二氢山奈酚。我们的结果表明，DFR的底物特异性可以通过DFR的微小变化来改变。
Many plant species exhibit a reduced range of flower colors due to the lack of an essential gene or to the substrate specificity of a biosynthetic enzyme. Petunia does not produce orange flowers because dihydroflavonol 4-reductase (DFR) from this species, an enzyme involved in anthocyanin biosynthesis, inefficiently reduces dihydrokaempferol, the precursor to orange pelargonidin-type anthocyanins. The substrate specificity of DFR, however, has not been investigated at the molecular level. By analyzing chimeric DFRs of Petunia and Gerbera, we identified a region that determines the substrate specificity of DFR. Furthermore, by changing a single amino acid in this presumed substrate-binding region, we developed a DFR enzyme that preferentially reduces dihydrokaempferol. Our results imply that the substrate specificity of DFR can be altered by minor changes in DFR.