The human low affinity Fcγ receptors IIa, IIb, and III bind IgG with fast kinetics and distinct thermodynamic properties
The human low affinity Fcγ receptors IIa, IIb, and III bind IgG with fast kinetics and distinct thermodynamic properties
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DOI：
10.1074/jbc.m106819200
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发表时间：
2001-11-30
影响因子：
4.8
通讯作者：
Sondermann, P
中科院分区：
文献类型：
--
作者：
Maenaka, K;van der Merwe, PA;Sondermann, P
Fc γ受体（Fc γ R）在所有免疫活性细胞上表达。它们结合IgG的Fe部分，从而触发一系列免疫功能。我们使用表面等离子体共振分析了人低亲和力Fc γ R（Fc γ RIIa、Fc γ RIIb和Fc γ RIIb-NA 2）的胞外域与IgG 1或IgG 1的Fc片段之间相互作用的动力学和热力学性质。所有三种受体以类似的低亲和力（K-D类似于0.6 -2.5 μ M）和快速动力学结合Fc或IgG，表明Fc γ R介导的聚集IgG和IgG包被颗粒或细胞的识别在机制上类似于细胞-细胞识别。有趣的是，Fe受体表现出不同的热力学性质。尽管Fc γ RIIa和Fc γ RIIb与Fe的结合是由有利的熵和熵变驱动的，但Fc γ RIII的结合的特征在于高度不利的熵变。尽管这些差异的结构基础仍有待确定，但它们表明与结合偶联的分子事件在低亲和力Fc γ R中不同。
Fc gamma receptors (Fc gamma Rs) are expressed on all immunologically active cells. They bind the Fe portion of IgG, thereby triggering a range of immunological functions. We have used surface plasmon resonance to analyze the kinetic and thermodynamic properties of the interactions between the ectodomains of human low affinity Fc gamma Rs (Fc gamma RIIa, Fc gamma RIIb, and Fc gamma gamma RIIb-NA2) and IgG1 or the Fc fragment of IgG1. All three receptors bind Fc or IgG with similarly low affinities (K-D similar to0.6-2.5 muM) and fast kinetics, suggesting that Fc gammaR-mediated recognition of aggregated IgG and IgG-coated particles or cells is mechanistically similar to cell-cell recognition. Interestingly, the Fe receptors exhibit distinct thermodynamic properties. Whereas the binding of the Fc gamma RIIa and Fc gamma RIIb to Fe is driven by favorable entropic and enthalpic changes, the binding of Fc gamma RIII is characterized by highly unfavorable entropic changes. Although the structural bases for these differences remain to be determined, they suggest that the molecular events coupled to the binding differ among the low affinity Fc gamma Rs.