Exploring Covalent Allosteric Inhibition of Antigen 85C from Mycobacterium tuberculosis by Ebselen Derivatives.
Exploring Covalent Allosteric Inhibition of Antigen 85C from Mycobacterium tuberculosis by Ebselen Derivatives.
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探索依布硒啉衍生物对结核分枝杆菌抗原 85C 的共价变构抑制。
DOI：
10.1021/acsinfecdis.7b00003
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发表时间：
2017-05-12
影响因子：
5.3
通讯作者：
Ronning DR
中科院分区：
文献类型：
--
作者：
Goins CM;Dajnowicz S;Thanna S;Sucheck SJ;Parks JM;Ronning DR
以前的研究确定依布硒啉作为结核分枝杆菌（Mtb）抗原85（Ag 85）复合物的有效体外和体内抑制剂，该复合物包含分枝杆菌细胞壁生物合成所需的三种同源酶。在这项研究中，Mtb Ag 85 C酶共结晶与叠氮基和金刚烷基依布硒啉衍生物，导致在两个晶体结构的2.01和1.30毫微米分辨率，分别。这两种结构显示出预期的共价修饰的溶剂可访问的，非催化Cys 209残基形成硒基硫键。两种硫醇改性剂的连续差异密度允许评估影响依布硒啉结合和抑制剂取向的相互作用，这在以前的Ag 85 C依布硒啉结构中是未观察到的。依布硒啉、金刚烷基依布硒啉和叠氮基依布硒啉的kinact/KI值支持所观察到的与Arg 239的建设性化学相互作用对于增加对Ag 85 C的体外功效的重要性。为了更好地理解这些依布硒啉衍生物的体外动力学性质，使用密度泛函理论计算了依布硒啉和两种衍生物的特定蛋白质-抑制剂相互作用的能量和相对反应自由能。这些研究进一步支持了依布硒啉和我们先前发表的依布硒啉库中两种选择的依布硒啉衍生物在动力学和蛋白质-抑制剂相互作用方面的不同体外性质。在这两种结构中，α9螺旋比之前的Ag 85 C ebselen结构更远离酶活性位点，导致连接环的重组，并赋予被认为在Ag 85 C特异性底物结合中发挥作用的残基构象变化。这些显着的结构变化直接影响蛋白质的稳定性，使整体熔融温度降低高达14.5 °C，导致蛋白质在生理温度下解折叠。此外，由于共价变构修饰导致的这种结构重排产生了相当大的溶剂网络，其包含活性位点并延伸至修饰的Cys 209残基。总之，本研究概述了影响依布硒啉及其衍生物的酶抑制的因素，同时进一步突出了所述抑制剂对Ag 85 C的结构和稳定性的Cys 209的共价修饰的影响。此外，这些结果表明了开发具有增加的特异性和效力的新型Ag 85抑制剂的策略。
Previous studies identified ebselen as a potent in vitro and in vivo inhibitor of the Mycobacterium tuberculosis (Mtb) antigen 85 (Ag85) complex, comprising three homologous enzymes required for the biosynthesis of the mycobacterial cell wall. In this study, the Mtb Ag85C enzyme was cocrystallized with azido and adamantyl ebselen derivatives, resulting in two crystallographic structures of 2.01 and 1.30 Å resolution, respectively. Both structures displayed the anticipated covalent modification of the solvent accessible, noncatalytic Cys209 residue forming a selenenylsulfide bond. Continuous difference density for both thiol modifiers allowed for the assessment of interactions that influence ebselen binding and inhibitor orientation that were unobserved in previous Ag85C ebselen structures. The kinact/KI values for ebselen, adamantyl ebselen, and azido ebselen support the importance of observed constructive chemical interactions with Arg239 for increased in vitro efficacy toward Ag85C. To better understand the in vitro kinetic properties of these ebselen derivatives, the energetics of specific protein−inhibitor interactions and relative reaction free energies were calculated for ebselen and both derivatives using density functional theory. These studies further support the different in vitro properties of ebselen and two select ebselen derivatives from our previously published ebselen library with respect to kinetics and protein−inhibitor interactions. In both structures, the α9 helix was displaced farther from the enzyme active site than the previous Ag85C ebselen structure, resulting in the restructuring of a connecting loop and imparting a conformational change to residues believed to play a role in substrate binding specific to Ag85C. These notable structural changes directly affect protein stability, reducing the overall melting temperature by up to 14.5 °C, resulting in the unfolding of protein at physiological temperatures. Additionally, this structural rearrangement due to covalent allosteric modification creates a sizable solvent network that encompasses the active site and extends to the modified Cys209 residue. In all, this study outlines factors that influence enzyme inhibition by ebselen and its derivatives while further highlighting the effects of the covalent modification of Cys209 by said inhibitors on the structure and stability of Ag85C. Furthermore, the results suggest a strategy for developing new classes of Ag85 inhibitors with increased specificity and potency.
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DOI：
10.1107/s0907444909029436
发表时间：
2009-10-01
影响因子：
2.2
作者：
Moriarty, Nigel W.;Grosse-Kunstleve, Ralf W.;Adams, Paul D.
通讯作者：
Adams, Paul D.
DOI：
10.1039/c5cp04668h
发表时间：
2015-11-21
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
--
作者：
Davis MR;Dougherty DA
通讯作者：
Dougherty DA
影响因子：
3.1
作者：
Armitige, LY;Jagannath, C;Norris, SJ
通讯作者：
Norris, SJ
影响因子：
15
作者：
DUFFY, EM;KOWALCZYK, PJ;JORGENSEN, WL
通讯作者：
JORGENSEN, WL
影响因子：
81.5
作者：
Pai, Madhukar;Behr, Marcel A.;Raviglione, Mario
通讯作者：
Raviglione, Mario