Probing the abilities of synthetically useful serine proteases to discriminate between the configurations of remote stereocenters using chiral aldehyde inhibitors
Probing the abilities of synthetically useful serine proteases to discriminate between the configurations of remote stereocenters using chiral aldehyde inhibitors
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DOI：
10.1021/ja952835t
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发表时间：
1996-01-24
影响因子：
15
通讯作者：
Jones, JB
中科院分区：
文献类型：
--
作者：
Lee, T;Jones, JB
利用手性醛过渡态类似物抑制剂作为探针，研究了合成有用的丝氨酸蛋白酶，枯草杆菌嘉士伯蛋白酶（SC）和α -胰凝乳蛋白酶（CT）区分远离催化位点的立体中心R-和s -构型的能力。所评价的抑制剂是(R)-和(S)-3-苯丁醛和(R)-和(S)-4-苯戊醛，它们在C-3和C-4的立体中心分别远离与催化丝氨酸残基相互作用的醛官能团。非手性亲本化合物，3-苯丙醛和4-苯丁醛也分别进行了评估，以供参考。研究发现，每一种醛都是两种酶的竞争性抑制剂，其中CT的抑制作用明显强于SC。在这个系列中，r中心甲基的存在显著改善了两种酶的结合，而不是非手性亲本醛。相反，对相同位置的s -甲基取代基结合的影响不大，通常是有害的。此外，立体中心与醛基的距离越大，构型辨别程度越低。CT对(R)-3-苯丁醛的抑制效果最好，远程立体中心识别程度最高，其K-I值为8.4 μ M，比其非手性亲本3-苯丙醛低61倍，比其s-对映体低6倍。通过分子力学和分子动力学计算，确定了每一种有利的醛酶复合物，并揭示了R-和s -对映体结合区别的结合和取向差异。
The abilities of the synthetically useful serine proteases, subtilisin Carlsberg (SC) and alpha-chymotrypsin (CT), to discriminate between R- and S-configurations of stereocenters remote from the catalytic site have been explored using chiral aldehyde transition state analog inhibitors as probes. The inhibitors evaluated were (R)- and (S)-3-phenylbutanal and (R)- and (S)-4-phenylpentanal, for which the stereocenters at C-3 and C-4 respectively are distant from the aldehyde functionality that interacts with the catalytic serine residue. The achiral parent compounds, 3-phenylpropanal and 4-phenylbutanal, respectively, were also assessed for reference purposes. Each aldehyde was found to be a competitive inhibitor for both enzymes, with CT being significantly more potently inhibited than SC. Within this series, the presence of an R-center methyl group improved binding significantly over that of the achiral parent aldehyde for both enzymes. In contrast, the effects on binding of S-methyl substituents in the same positions were modest, and generally somewhat deleterious. Furthermore, the greater the separation of the stereocenter from the aldehyde group, the lower the degree of configuration discrimination. The most effective inhibition, and the highest degree of remote stereocenter discrimination, observed was that by CT of (R)-3-phenylbutanal, whose K-I of 8.4 mu M was 61-fold lower than that of its achiral parent 3-phenylpropanal, and ss-fold lower than the K-I of its S-enantiomer. Molecular mechanics and molecular dynamics calculations were performed to identify each favored aldehyde-enzyme complex and to reveal the binding and orientation differences responsible for the R- and S-enantiomer binding discriminations observed.