Identification of Contact Residues in the IgE Binding Site of Human FcRI
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- 作者：Justin P. D. Cook ; Alistair J. Henry ; James M. McDonnell ; Raymond J. Owens ; Brian J. Sutton ; and Hannah J. Gould
- 刊名：Biochemistry
- 出版年：1997
- 出版时间：December 16, 1997
- 年：1997
- 卷：36
- 期：50
- 页码：15579 - 15588
- 全文大小：240K
- 年卷期：v.36,no.50(December 16, 1997)
- ISSN：1520-4995
文摘
The high-affinity receptor for immunoglobulin E (IgE), Fc
RI, isan 
2 tetramer found onmast cells, basophils, and several other types of immune effectorcells. The interaction of IgE with the-subunit of FcRI is central to the pathogenesis of allergy.Detailed knowledge of the mode of interactionof FcRI with IgE may facilitate the development of inhibitors forgeneral use in the treatment of allergicdisease. To this end we have performed site-directed mutagenesison a soluble form of the FcRI -chain(sFcRI). The effects of four mutations in the secondimmunoglobulin-like domain of sFcRI uponthe kinetics of binding to IgE and fragments of IgE have been analyzedusing surface plasmon resonance.As described in the preceding paper of this issue [Henry, A. J.,et al. (1997) Biochemistry 36,15568-15578], biphasic binding kinetics was observed. Two of themutations had significant effects onbinding: K117D reduced the affinity of sFcRI for IgE by afactor of 30, while D159K increased theaffinity for IgE by a factor of 7, both principally through changes inthe rates of dissociation of theslower phase of the interaction. Circular dichroism spectra ofsFcRI incorporating either of these mutations were indistinguishable from those of wild-type sFcRI,demonstrating that the native conformationhad not been disrupted. Our results, together with those fromsite-directed mutagenesis on fragments ofIgE presented in the accompanying paper, define the contact surfaces inthe IgE:sFcRI complex.
RI, isan 2 tetramer found onmast cells, basophils, and several other types of immune effectorcells. The interaction of IgE with the-subunit of FcRI is central to the pathogenesis of allergy.Detailed knowledge of the mode of interactionof FcRI with IgE may facilitate the development of inhibitors forgeneral use in the treatment of allergicdisease. To this end we have performed site-directed mutagenesison a soluble form of the FcRI -chain(sFcRI). The effects of four mutations in the secondimmunoglobulin-like domain of sFcRI uponthe kinetics of binding to IgE and fragments of IgE have been analyzedusing surface plasmon resonance.As described in the preceding paper of this issue [Henry, A. J.,et al. (1997) Biochemistry 36,15568-15578], biphasic binding kinetics was observed. Two of themutations had significant effects onbinding: K117D reduced the affinity of sFcRI for IgE by afactor of 30, while D159K increased theaffinity for IgE by a factor of 7, both principally through changes inthe rates of dissociation of theslower phase of the interaction. Circular dichroism spectra ofsFcRI incorporating either of these mutations were indistinguishable from those of wild-type sFcRI,demonstrating that the native conformationhad not been disrupted. Our results, together with those fromsite-directed mutagenesis on fragments ofIgE presented in the accompanying paper, define the contact surfaces inthe IgE:sFcRI complex.