Isothermal Titration Calorimetry for Characterizing the Zinc(II)‐Binding Properties of Photocaged Complexes with Micromolar Affinity
Isothermal Titration Calorimetry for Characterizing the Zinc(II)‐Binding Properties of Photocaged Complexes with Micromolar Affinity
复制标题
等温滴定量热法表征具有微摩尔亲和力的光笼配合物的锌 (II) 结合特性
DOI：
10.1002/anse.202200043
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Burdette, Shawn C.
中科院分区：
文献类型：
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作者：
Hickey, Erin E.;Shigemoto, Austin;Gericke, Arne;Burdette, Shawn C.
MorphDeCage（2-（4-甲氧基-3-硝基苯基）-2-吗啉代乙酸）和PyrDeCage（2-（4-甲氧基-3-硝基苯基）-2-（甲基（吡啶-2-基甲基）氨基）乙酸）是利用间硝基苯乙酸的甲氧基衍生物的光脱羧作用作为释放机制的Zn 2+光笼。由于用4-（2-吡啶偶氮）间苯二酚（PAR）竞争滴定法测量不成功，因此使用等温滴定量热法（ITC）替代常规方法来测量这些新化合物的Zn 2+结合亲和力。MorphDeCage形成1：1配体-金属络合物，Kd值为106 μM。 PyrDeCage可形成1：1和1：2金属：配体络合物，Kd值分别为3.2和21.7 μM。 为了进一步证明ITC方法的有效性并提供与直接紫外-维斯滴定数据的比较，制备了两种基于桑格试剂（SRP）的光笼。通过UV-维斯滴定和ITC测量的SRP的Kd值内部一致，并支持撤回原始报告（J. Am. Soc.2020，142，3806-3813），由于结合亲和力测量中的误差而被撤回。
MorphDeCage (2‐(4‐methoxy‐3‐nitrophenyl)‐2‐morpholinoacetic acid) and PyrDeCage (2‐(4‐methoxy‐3‐nitrophenyl)‐2‐(methyl(pyridin‐2‐ylmethyl)amino)acetic) are Zn2+photocages that utilize photodecarboxylation of the methoxy derivative ofmeta‐nitrophenylacetic acid as the release mechanism. Isothermal titration calorimetry (ITC) was used an alternative to usual approaches to measure the Zn2+binding affinities of these new compounds owing to unsuccessful measurement by competitive titration with 4‐(2‐pyridylazo)resorcinol (PAR). MorphDeCage forms a 1 : 1 ligand‐metal complex with a 106 μM Kdvalue. PyrDeCage forms both a 1 : 1 and 1 : 2 metal: ligand complexes with 3.2 and 21.7 μM Kdvalues respectively. To further demonstrate the efficacy of the ITC methodology and provide a comparison to direct UV‐vis titrations data, two photocages based on Sanger's reagent (SRPs) were prepared. The Kdvalues of the SRPs measured by UV‐vis titration and ITC were internally consistent and support the retraction of the original report (J. Am. Chem. Soc.2020,142, 3806–3813), which was withdrawn due to errors in binding affinity measurements.