Solvent-assisted slow conversion of a dithiazole derivative produces a competitive inhibitor of peptide deformylase
Solvent-assisted slow conversion of a dithiazole derivative produces a competitive inhibitor of peptide deformylase
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DOI：
10.1016/j.bbapap.2009.11.006
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发表时间：
2010-04-01
影响因子：
3.2
通讯作者：
Srivastava, D. K.
中科院分区：
文献类型：
--
作者：
Berg, Alexander K.;Yu, Qingfeng;Srivastava, D. K.
由于其作为抗生素靶标的潜力，大肠杆菌肽脱甲酰基酶（PDFEC）作为抑制剂设计的模型酶系统。在研究这种酶的结构-功能和抑制特征时，我们意外地发现，当上述化合物仅溶解在二甲基甲酰胺（DMF）中而不溶解在任何其他溶剂中并允许老化时，2-氨基-5-巯基-1，3，4-噻二唑（AMT）充当PDFEC的缓慢结合抑制剂。DMF溶解的AMT的时间依赖性抑制效力与抑制剂的295 nm光谱带向可见光区域的加宽相关，伴随着母体化合物的质量增加约2倍。这些数据表明DMF促进AMT的缓慢二聚化（通过形成二硫键），并且AMT的二聚体形式用作PDFEC的抑制剂。后者不是由氧化剂如H2 O2简单氧化巯基引起的。新合成的AMT的二聚体/二硫醇化形式（“bis-AMT”）在与DMF孵育时表现出与母体化合物相似的光谱和抑制特征。计算机图形建模数据显示，双AMT可以可靠地容纳在PDFEC的活性位点口袋内，上述酶-配体相互作用涉及与酶常驻Ni 2+辅因子的配位。DMF辅助激活AMT（生成bis-AMT）的机制，整个微观途径的缓慢结合抑制PDFEC的bis-AMT，和潜在的bis-AMT作为一类新的抗生素剂。(C)2009 Elsevier B. V.保留所有权利。
Due to its potential as an antibiotic target, E coli peptide deformylase (PDFEC) serves as a model enzyme system for inhibitor design. While investigating the structural-functional and inhibitory features of this enzyme, we unexpectedly discovered that 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) served as a slow-binding inhibitor of PDFEC when the above compound was dissolved only in dimethylformamide (DMF), but not in any other solvent, and allowed to age. The time dependent inhibitory potency of the DMF-dissolved AMT was correlated with the broadening of the inhibitor's 295 nm spectral band toward the visible region, concomitant with the increase in the mass of the parent compound by about 2-fold. These data led to the suggestion that DMF facilitated the slow dimerization of AMT (via the formation of a disulfide bond), and that the dimeric form of AMT served as an inhibitor for PDFEC. The latter is not caused by the simple oxidation of sulfhydryl groups by oxidizing agents such as H2O2. Newly synthesized dimeric/dithiolated form of AMT ("bis-AMT") exhibited similar spectral and inhibitory features as given by the parent compound when incubated with DMF. The computer graphic modeling data revealed that bis-AMT could be reliably accommodated within the active site pocket of PDFEC, and the above enzyme-ligand interaction involves coordination with the enzyme resident Ni2+ cofactor. The mechanism of the DMF-assisted activation of AMT (generating bis-AMT), the overall microscopic pathway for the slow-binding inhibition of PDFEC by bis-AMT, and the potential of bis-AMT to serve as a new class of antibiotic agent are presented. (C) 2009 Elsevier B.V. All rights reserved.