Rational Design of Aziridine‐Containing Cysteine Protease Inhibitors with Improved Potency: Studies on Inhibition Mechanism
Rational Design of Aziridine‐Containing Cysteine Protease Inhibitors with Improved Potency: Studies on Inhibition Mechanism
复制标题
合理设计具有改进效力的含氮丙啶半胱氨酸蛋白酶抑制剂：抑制机制研究
DOI：
10.1002/cmdc.200600081
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发表时间：
2006
期刊：
影响因子：
3.4
通讯作者：
B. Engels
中科院分区：
文献类型：
--
作者：
R. Vičík;Holger Helten;T. Schirmeister;B. Engels
为了能够合理设计改进的半胱氨酸蛋白酶抑制剂，目前的工作调查的趋势，氮杂环丙烷衍生物的抑制效力与取代的氮中心。为了预测吸电子取代基的影响，进行了N-甲酰化、N-甲基化和N-未取代氮杂环丙烷与硫醇盐开环的量子化学计算。他们发现，N-甲酰基基团导致反应势垒的强烈降低和由于过渡态的稳定而导致的显着增加。相比之下，在羰基碳原子的亲核攻击的特征在于非常低的反应势垒，这表明可逆反应，从而提供了由肽基醛可逆抑制半胱氨酸蛋白酶的理论背景。氮丙啶结构单元（氮丙啶-2，3-二羧酸二乙酯1、1-甲酰基氮丙啶-2，3-二羧酸二乙酯2）与模型硫醇盐在水溶液中的反应，随后进行NMR光谱和质谱分析，显示N-甲酰基化化合物2容易进行开环反应。相比之下，1与硫醇盐的反应慢得多。半胱氨酸蛋白酶组织蛋白酶L的酶测定显示2是比1好5000倍的酶抑制剂。 透析试验清楚地证明了不可逆抑制。这些实验以及用模型硫醇盐获得的结果表明，N-甲酰化氮丙啶2的主要抑制机制是开环反应，而不是活性位点半胱氨酸残基在羰基碳原子处的可逆攻击。
To enable a rational design of improved cysteine protease inhibitors, the present work investigates trends in the inhibition potency of aziridine derivatives with a substituted nitrogen center. To predict the influence of electron‐withdrawing substituents, quantum chemical computations of the ring opening of N‐formylated, N‐methylated, and N‐unsubstituted aziridines with thiolate were performed. They revealed that the N‐formyl group leads to a strong decrease of the reaction barrier and a considerable increase in exothermicity due to stabilization of the transition state. In contrast, a nucleophilic attack at the carbonyl carbon atom is characterized by very low reaction barriers, suggesting a reversible reaction, thus providing the theoretical background for the reversible inhibition of cysteine proteases by peptidyl aldehydes. Reactions of aziridine building blocks (diethyl aziridine‐2,3‐dicarboxylate 1, diethyl 1‐formyl aziridine‐2,3‐dicarboxylate 2) with a model thiolate in aqueous solution which were followed by NMR spectroscopy and mass spectrometry, showed the N‐formylated compound 2 to readily undergo a ring‐opening reaction. In contrast, the reaction of 1 with the thiolate is much slower. Enzyme assays with the cysteine protease cathepsin L showed 2 to be a 5000‐fold better enzyme inhibitor than 1. Dialysis assays clearly proved irreversible inhibition. These experiments, together with the results obtained with the model thiolate, indicate that the main inhibition mechanism of the N‐formylated aziridine 2 is the ring‐opening reaction rather than the reversible attack of the active site cysteine residue at the carbonyl carbon atom.