Calorimetric assessment of Fe(2+) binding to α-ketoglutarate/taurine dioxygenase: ironing out the energetics of metal coordination by the 2-His-1-carboxylate facial triad.
Calorimetric assessment of Fe(2+) binding to α-ketoglutarate/taurine dioxygenase: ironing out the energetics of metal coordination by the 2-His-1-carboxylate facial triad.
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DOI：
10.1021/ic502881q
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发表时间：
2015-03-02
影响因子：
4.6
通讯作者：
Emerson JP
中科院分区：
文献类型：
--
作者：
Henderson KL;Müller TA;Hausinger RP;Emerson JP
The thermodynamic properties of Fe2+ binding to the 2-His-1-carboxylate facial triad in α-ketoglutarate/taurine dioxygenase (TauD) were explored using isothermal titration calorimetry. Direct titrations of Fe2+ into TauD and chelation experiments involving the titration of ethylenediaminetetraacetic acid into Fe2+-TauD were performed under an anaerobic environment to yield a binding equilibrium of 2.4 (± 0.1) × 107 (Kd = 43 nM), and a ΔG° of −10.1 (± 0.03) kcal/mol. Further analysis of the enthalpy/entropy contributions indicate a highly enthalpic binding event, where ΔH = −11.64 (± 0.25) kcal/mol. Investigations into the unfavorable entropy term led to the observation of approximately 6.5 water molecules becoming organized within the Fe2+-TauD structure. Thermodynamic profile associated with Fe2+ binding to the 2-His-1-carboxylate facial triad in TauD.
