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• 作者：Anna Starus ; Boguslaw Nocek ; Brian Bennett ; James A. Larrabee ; Daniel L. Shaw ; Wisath Sae-Lee ; Marie T. Russo ; Danuta M. Gillner ; Magdalena Makowska-Grzyska ; Andrzej Joachimiak ; Richard C. Holz
• 刊名：Biochemistry
• 出版年：2015
• 出版时间：August 11, 2015
• 年：2015
• 卷：54
• 期：31
• 页码：4834-4844
• 全文大小：416K
• ISSN：1520-4995

文摘

Binding of the competitive inhibitor l-captopril to the dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase from Neisseria meningitidis (NmDapE) was examined by kinetic, spectroscopic, and crystallographic methods. l-Captopril, an angiotensin-converting enzyme (ACE) inhibitor, was previously shown to be a potent inhibitor of the DapE from Haemophilus influenzae (HiDapE) with an IC₅₀ of 3.3 渭M and a measured K_i of 1.8 渭M and displayed a dose-responsive antibiotic activity toward Escherichia coli. l-Captopril is also a competitive inhibitor of NmDapE with a K_i of 2.8 渭M. To examine the nature of the interaction of l-captopril with the dinuclear active site of DapE, we have obtained electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) data for the enzymatically hyperactive Co(II)-substituted forms of both HiDapE and NmDapE. EPR and MCD data indicate that the two Co(II) ions in DapE are antiferromagnetically coupled, yielding an S = 0 ground state, and suggest a thiolate bridge between the two metal ions. Verification of a thiolate-bridged dinuclear complex was obtained by determining the three-dimensional X-ray crystal structure of NmDapE in complex with l-captopril at 1.8 脜 resolution. Combination of these data provides new insights into binding of l-captopril to the active site of DapE enzymes as well as important inhibitor鈥揳ctive site residue interaction鈥檚. Such information is critical for the design of new, potent inhibitors of DapE enzymes.