A Standalone ß-Ketoreductase Acts Concomitantly with Biosynthesis of the Antimycin Scaffold.
A Standalone ß-Ketoreductase Acts Concomitantly with Biosynthesis of the Antimycin Scaffold.
复制标题
独立的酮还原酶与抗霉素支架的生物合成同时起作用。
DOI：
10.1021/acschembio.1c00229
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发表时间：
2021
影响因子：
4
通讯作者：
Fazal A
中科院分区：
文献类型：
--
作者：
Fazal A
抗霉素是由杂合非核糖体肽合成酶/聚酮合酶（NRPS/PKS）途径产生的抗癌化合物。这些化合物的生物合成得到了充分表征，但单独的β-酮还原酶AntM除外，该酶被提议催化抗霉素支架的C8羰基的还原。antM的失活和结构表征表明，而不是作为一个后PKS剪裁酶，AntM作用于末端生物合成中间体，而它是拴在PKS酰基载体蛋白。突变分析鉴定了两个氨基酸残基（Tyr 185和Phe 223），其被提议用作控制底物进入AntM活性位点的检查点。芳香族检查点残基在未表征的独立β-酮还原酶中是保守的，表明它们也可能与支架的合成同时起作用。这些数据为独立β-酮还原酶的功能提供了新的机制见解，并将使其能够重新编程用于组合生物合成。
Antimycins are anticancer compounds produced by a hybrid nonribosomal peptide synthetase/polyketide synthase (NRPS/PKS) pathway. The biosynthesis of these compounds is well characterized, with the exception of the standalone β-ketoreductase enzyme AntM that is proposed to catalyze the reduction of the C8 carbonyl of the antimycin scaffold. Inactivation ofantMand structural characterization suggested that rather than functioning as a post-PKS tailoring enzyme, AntM acts upon the terminal biosynthetic intermediate while it is tethered to the PKS acyl carrier protein. Mutational analysis identified two amino acid residues (Tyr185 and Phe223) that are proposed to serve as checkpoints controlling substrate access to the AntM active site. Aromatic checkpoint residues are conserved in uncharacterized standalone β-ketoreductases, indicating that they may also act concomitantly with synthesis of the scaffold. These data provide novel mechanistic insights into the functionality of standalone β-ketoreductases and will enable their reprogramming for combinatorial biosynthesis.