化学
生物物理学
表面等离子共振
结合位点
吞噬作用
离解常数
合作约束
血浆蛋白结合
组氨酸
二价(发动机)
离解(化学)
受体
抗体
生物化学
细胞生物学
生物
金属
纳米技术
纳米颗粒
免疫学
酶
材料科学
物理化学
有机化学
作者
Andrew B. Herr,Clinton L White,Christina Milburn,Carol A. Wu,Pamela J. Björkman
标识
DOI:10.1016/s0022-2836(03)00149-9
摘要
FcαRI, the receptor specific for the Fc region of immunoglobulin A (IgA), is responsible for IgA-mediated phagocytosis, oxidative burst, and antibody-dependent cellular cytotoxicity. Using the techniques of analytical ultracentrifugation and equilibrium gel-filtration, we show that two FcαRI molecules bind to a single Fcα homodimer. Surface plasmon resonance studies confirm the 2:1 stoichiometry of binding, with equilibrium dissociation constants of 176 nM and 431 nM for the first and second binding events, respectively. The binding affinity decreases at acidic pH in a manner consistent with protonation of a single histidine residue in the binding site. A thermodynamic analysis indicates that the histidine residue does not participate in a salt-bridge in the complex; in fact, less than 10% of the free energy of binding was contributed by electrostatic interactions. The bivalent, pH-dependent interaction between FcαRI and IgA has important implications for cytokine-dependent phagocytosis of IgA and the FcαRI-mediated degradation or recycling of IgA.
科研通智能强力驱动
Strongly Powered by AbleSci AI