Department Pharmaceutical Microbiology, Hans-Knöll-Institute, Friedrich-Schiller-Universität, Beutenbergstrasse 11a, 07745, Jena, Germany.
Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Albertstrasse 25, 79104, Freiburg, Germany.
Chembiochem. 2023 Feb 1;24(3):e202200649. doi: 10.1002/cbic.202200649. Epub 2022 Dec 28.
The nonreducing iterative type I polyketide synthases (NR-PKSs) CoPKS1 and CoPKS4 of the webcap mushroom Cortinarius odorifer share 88 % identical amino acids. CoPKS1 almost exclusively produces a tricyclic octaketide product, atrochrysone carboxylic acid, whereas CoPKS4 shows simultaneous hepta- and octaketide synthase activity and also produces the bicyclic heptaketide 6-hydroxymusizin. To identify the region(s) controlling chain length, four chimeric enzyme variants were constructed and assayed for activity in Aspergillus niger as heterologous expression platform. We provide evidence that the β-ketoacyl synthase (KS) domain determines chain length in these mushroom NR-PKSs, even though their KS domains differ in only ten amino acids. A unique proline-rich linker connecting the acyl carrier protein with the thioesterase domain varies most between these two enzymes but is not involved in chain length control.
网孢牛肝菌（Cortinarius odorifer）中的非还原型 I 型聚酮合酶（NR-PKS）CoPKS1 和 CoPKS4 有 88%的氨基酸序列相同。CoPKS1 几乎只产生三环八酮产物阿托曲酸羧酸，而 CoPKS4 则表现出同时具有七酮和八酮合酶活性，并产生双环七酮 6-羟基马素辛。为了确定控制链长的区域，构建了四个嵌合酶变体，并在黑曲霉中作为异源表达平台进行了活性测定。我们提供的证据表明，β-酮酰基合酶（KS）结构域决定了这些蘑菇 NR-PKS 的链长，尽管它们的 KS 结构域仅在十个氨基酸上存在差异。连接酰基载体蛋白与硫酯酶结构域的独特脯氨酸丰富连接子在这两种酶之间变化最大，但不参与链长控制。
