Structural Basis for the Selective Binding of Inhibitors to 6-Hydroxymethyl-7,8-dihydropterin Pyrophosphokinase from Staphylococcus aureus and Escherichia coli

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• 作者：Matthew L. Dennis ; Noel P. Pitcher ; Michael D. Lee ; Aaron J. DeBono ; Zhong-Chang Wang ; Jitendra R. Harjani ; Raphaël Rahmani ; Ben Cleary ; Thomas S. Peat ; Jonathan B. Baell ; James D. Swarbrick
• 刊名：Journal of Medicinal Chemistry
• 出版年：2016
• 出版时间：June 9, 2016
• 年：2016
• 卷：59
• 期：11
• 页码：5248-5263
• 全文大小：754K
• 年卷期：0
• ISSN：1520-4804

文摘

6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is a member of the folate biosynthesis pathway found in prokaryotes and lower eukaryotes that catalyzes the pyrophosphoryl transfer from the ATP cofactor to a 6-hydroxymethyl-7,8-dihydropterin substrate. We report the chemical synthesis of a series of S-functionalized 8-mercaptoguanine (8MG) analogues as substrate site inhibitors of HPPK and quantify binding against the E. coli and S. aureus enzymes (EcHPPK and SaHPPK). The results demonstrate that analogues incorporating acetophenone-based substituents have comparable affinities for both enzymes. Preferential binding of benzyl-substituted 8MG derivatives to SaHPPK was reconciled when a cryptic pocket unique to SaHPPK was revealed by X-ray crystallography. Differential chemical shift perturbation analysis confirmed this to be a common mode of binding for this series to SaHPPK. One compound (41) displayed binding affinities of 120 nM and 1.76 μM for SaHPPK and EcHPPK, respectively, and represents a lead for the development of more potent and selective inhibitors of SaHPPK.