College of Chemical Engineering, Huaqiao University, Xiamen, China.
PLoS One. 2021 Dec 2;16(12):e0260787. doi: 10.1371/journal.pone.0260787. eCollection 2021.
The biosynthesis of chiral alcohols has important value and high attention. Aldo-keto reductases (AKRs) mediated reduction of prochiral carbonyl compounds is an interesting way of synthesizing single enantiomers of chiral alcohols due to the high enantio-, chemo- and regioselectivity of the enzymes. However, relatively little research has been done on characterization and apply of AKRs to asymmetric synthesis of chiral alcohols. In this study, the AKR from Candida tropicalis MYA-3404 (C. tropicalis MYA-3404), was mined and characterized. The AKR shown wider optimum temperature and pH. The AKR exhibited varying degrees of catalytic activity for different substrates, suggesting that the AKR can catalyze a variety of substrates. It is worth mentioning that the AKR could catalytic reduction of keto compounds with benzene rings, such as cetophenone and phenoxyacetone. The AKR exhibited activity on N,N-dimethyl-3-keto-3-(2-thienyl)-1-propanamine (DKTP), a key intermediate for biosynthesis of the antidepressant drug duloxetine. Besides, the AKR still has high activity whether in a reaction system containing 10%-30% V/V organic solvent. What's more, the AKR showed the strongest stability in six common organic solvents, DMSO, acetonitrile, ethyl acetate, isopropanol, ethanol, and methanol. And, it retains more that 70% enzyme activity after 6 hours, suggesting that the AKR has strong solvent tolerance. Furthermore, the protein sequences of the AKR and its homology were compared, and a 3D model of the AKR docking with coenzyme NADPH were constructed. And the important catalytic and binding sites were identified to explore the binding mechanism of the enzyme and its coenzyme. These properties, predominant organic solvents resistance and extensive substrate spectrum, of the AKR making it has potential applications in the pharmaceutical field.
手性醇的生物合成具有重要的价值和高度的关注。醛酮还原酶（AKR）介导的前手性羰基化合物的还原是合成单一对映体手性醇的一种有趣方法，因为酶具有高对映选择性、化学选择性和区域选择性。然而，相对较少的研究致力于 AKR 的特性和应用于手性醇的不对称合成。在本研究中，从热带假丝酵母 MYA-3404（Candida tropicalis MYA-3404）中挖掘并表征了 AKR。该 AKR 显示出更宽的最佳温度和 pH 值。该 AKR 对不同的底物表现出不同程度的催化活性，表明该 AKR 可以催化多种底物。值得一提的是，该 AKR 可以催化带有苯环的酮类化合物的还原，如苯乙酮和苯氧乙酮。该 AKR 对 N,N-二甲基-3-酮-3-（2-噻吩基）-1-丙胺（DKTP）表现出活性，DKTP 是抗抑郁药度洛西汀生物合成的关键中间体。此外，该 AKR 在含有 10%-30%V/V 有机溶剂的反应体系中仍然具有很高的活性。更重要的是，该 AKR 在六种常见有机溶剂（DMSO、乙腈、乙酸乙酯、异丙醇、乙醇和甲醇）中表现出最强的稳定性。并且，它在 6 小时后保留了超过 70%的酶活性，表明该 AKR 具有很强的溶剂耐受性。此外，比较了 AKR 的蛋白序列及其同源性，并构建了 AKR 与辅酶 NADPH 对接的 3D 模型。并确定了重要的催化和结合位点，以探索酶及其辅酶的结合机制。这些特性，包括优越的有机溶剂耐受性和广泛的底物谱，使 AKR 在手性醇的生物合成中具有潜在的应用前景。
