Structural insight into chain-length control and product specificity of pentaketide chromone synthase from Aloe arborescens
Structural insight into chain-length control and product specificity of pentaketide chromone synthase from Aloe arborescens
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DOI：
10.1016/j.chembiol.2007.02.003
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发表时间：
2007-04-01
影响因子：
--
通讯作者：
Kohno, Toshiyuki
中科院分区：
文献类型：
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作者：
Morita, Hiroyuki;Kondo, Shin;Kohno, Toshiyuki
野生型和突变体PCS，一种新的植物III型聚酮合酶从药用植物，木立芦荟，的晶体结构，解决了在1.6埃分辨率。晶体结构显示，生产pentaketide的野生型和生产octaketide的M207 G突变体共享几乎相同的整体折叠，并且大到小的取代通过打开通向酶活性位点后面的两个隐藏口袋的门来显著增加聚酮延长隧道的体积。因此，化学惰性活性位点残基207控制丙二酰-CoA的缩合次数，仅取决于侧链的空间体积。这些发现不仅提供了深入了解聚酮化合物的形成反应，但他们也建议策略的聚酮化合物的工程生物合成。
The crystal structures of a wild-type and a mutant PCS, a novel plant type III polyketide synthase from a medicinal plant, Aloe arborescens, were solved at 1.6 angstrom resolution. The crystal structures revealed that the pentaketide-producing wild-type and the octaketide-producing M207G mutant shared almost the same overall folding, and that the large-to-small substitution dramatically increases the volume of the polyketicle-elongation tunnel by opening a gate to two hidden pockets behind the active site of the enzyme. The chemically inert active site residue 207 thus controls the number of condensations of malonyl-CoA, solely depending on the steric bulk of the side chain. These findings not only provided insight into the polyketide formation reaction, but they also suggested strategies for the engineered biosynthesis of polyketides.