A biosensor study indicating that entropy, electrostatics, and receptor glycosylation drive the binding interaction between interleukin-7 and its receptor.
A biosensor study indicating that entropy, electrostatics, and receptor glycosylation drive the binding interaction between interleukin-7 and its receptor.
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DOI：
10.1021/bi101050h
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发表时间：
2010-10-12
期刊：
影响因子：
2.9
通讯作者：
Walsh, Scott T. R.
中科院分区：
文献类型：
--
作者：
Walsh, Scott T. R.
白细胞介素-7（IL-7）及其α受体IL-7 R α之间的相互作用在B细胞和T细胞的发育、存活和稳态中起着重要作用。人IL-7 R α的N-连接糖基化通过变构机制使其与人IL-7的结合亲和力比非糖基化受体提高300倍。IL-7 R α的N-聚糖不直接参与与IL-7的结合界面。该生物物理学研究涉及使用表面等离子体共振（SPR）光谱分析IL-7与非糖基化和糖基化形式的IL-7 R α胞外结构域（ECD）的结合特性，作为盐、pH值和温度的函数。随着盐浓度的增加，IL-7与两种IL-7 R α变体的相互作用显示出较弱的结合亲和力，这主要反映在两步反应途径的首次结合速率的变化上。IL-7/IL-7 R α相互作用的静电参数不是由通过结合界面残基或IL-7 R α N-聚糖组成的互补电荷相互作用驱动的，而是可能由两种蛋白质的有利全局电荷驱动的。Van 't霍夫分析表明，IL-7/IL-7 R α相互作用均由较大的有利熵变和较小的不利（非糖基化复合物）和有利（糖基化复合物）焓变驱动。对IL-7/IL-7 R α相互作用的Eyring分析揭示了IL-7转化为非糖基化和糖基化IL-7 R α的焓变和熵变的不同反应途径和过渡态热力学势垒。IL-7/IL-7 R α相互作用的平衡或过渡态结合热力学没有明显的热容变化。此处的结果表明，相对于未结合的糖基化IL-7 R α，未结合的非糖基化IL-7 R α采样了广泛的构象景观，这可能解释了从非糖基化相互作用的“构象”控制反应（k1 ~102 M− 1 s −1）到糖基化相互作用的“扩散”控制反应（k1 ~106 M− 1 s −1）的转变。因此，较大的有利熵变、全局有利静电分量和受体的糖基化（尽管不是在界面处）显著促进了IL-7和IL-7 R α ECD之间的相互作用。
The interaction between interleukin-7 (IL-7) and its α-receptor, IL-7Rα, plays fundamental roles in the development, survival, and homeostasis of B- and T-cells. N-linked glycosylation of human IL-7Rα enhances its binding affinity to human IL-7 by 300-fold over the nonglycosylated receptor through an allosteric mechanism. The N-glycans of IL-7Rα do not participate directly in the binding interface with IL-7. This biophysical study involves dissection of the binding properties of IL-7 to both nonglycosylated and glycosylated forms of the IL-7Rα extracellular domain (ECD) as functions of salt, pH, and temperature using surface plasmon resonance (SPR) spectroscopy. Interactions of IL-7 to both IL-7Rα variants display weaker binding affinities with increasing salt concentrations primarily reflected by changes in the first on-rates of a two-step reaction pathway. The electrostatic parameter of the IL-7/IL-7Rα interaction is not driven by complementary charge interactions through residues at the binding interface or N-glycan composition of IL-7Rα, but presumably by favorable global charges of the two proteins. Van’t Hoff analysis indicates both IL-7/IL-7Rα interactions are driven by large favorable entropy changes and smaller unfavorable (nonglycosylated complex) and favorable (glycosylated complex) enthalpy changes. Eyring analysis of the IL-7/IL-7Rα interactions reveals different reaction pathways and barriers for the transition-state thermodynamics with the enthalpy and entropy changes of IL-7 to nonglycosylated and glycosylated IL-7Rα. There were no discernable heat capacity changes for the equilibrium or transition-state binding thermodynamics of the IL-7/IL-7Rα interactions. The results here suggest that the unbound nonglycosylated IL-7Rα samples an extensive conformational landscape relative to the unbound glycosylated IL-7Rα, potentially explaining the switch from a “conformational” controlled reaction (k1 ~102 M−1s−1) for the nonglycosylated interaction to a “diffusion” controlled reaction (k1 ~106 M−1s−1) for the glycosylated interaction. Thus, a large favorable entropy change, a global favorable electrostatic component, and glycosylation of the receptor—albeit not at the interface—contribute significantly to the interaction between IL-7 and IL-7Rα ECD.
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影响因子：
2.9
作者：
Darling, RJ;Kuchibhotla, U;Beals, JM
通讯作者：
Beals, JM
影响因子：
4.8
作者：
JOHANSON, K;APPELBAUM, E;CHAIKEN, I
通讯作者：
CHAIKEN, I
DOI：
10.1016/j.str.2008.10.019
发表时间：
2009-01-14
期刊：
Structure (London, England : 1993)
影响因子：
--
作者：
McElroy CA;Dohm JA;Walsh ST
通讯作者：
Walsh ST
DOI：
10.1073/pnas.0810318105
发表时间：
2009-03-03
影响因子：
11.1
作者：
Hanson, Sarah R.;Culyba, Elizabeth K.;Powers, Evan T.
通讯作者：
Powers, Evan T.
影响因子：
1.4
作者：
Ji, Rui-Cheng
通讯作者：
Ji, Rui-Cheng