Structural insights into the interaction of human IgG1 with FcγRI: no direct role of glycans in binding
- MedImmune LLC, 1 MedImmune Way, Gaithersburg, MD 20878 (United States)
- AstraZeneca Pharmaceuticals, 35 Gatehouse Drive, Mailstop E3, Waltham, MA 02451 (United States)
In an effort to identify the critical structural features responsible for the high-affinity interaction of IgG1 Fc with FcγRI, the structure of the corresponding complex was solved at a resolution of 2.4 Å. The three-dimensional structure of a human IgG1 Fc fragment bound to wild-type human FcγRI is reported. The structure of the corresponding complex was solved at a resolution of 2.4 Å using molecular replacement; this is the highest resolution achieved for an unmutated FcγRI molecule. This study highlights the critical structural and functional role played by the second extracellular subdomain of FcγRI. It also explains the long-known major energetic contribution of the Fc ‘LLGG’ motif at positions 234–237, and particularly of Leu235, via a ‘lock-and-key’ mechanism. Finally, a previously held belief is corrected and a differing view is offered on the recently proposed direct role of Fc carbohydrates in the corresponding interaction. Structural evidence is provided that such glycan-related effects are strictly indirect.
- OSTI ID:
- 22515197
- Journal Information:
- Acta Crystallographica. Section D: Biological Crystallography, Vol. 71, Issue Pt 11; Other Information: PMCID: PMC4631484; PMID: 26527150; PUBLISHER-ID: wa5098; OAI: oai:pubmedcentral.nih.gov:4631484; Copyright (c) Oganesyan et al. 2015; This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0907-4449
- Country of Publication:
- Denmark
- Language:
- English
Similar Records
Mouse IgG2c Fc loop residues promote greater receptor-binding affinity than mouse IgG2b or human IgG1
A single amino acid distorts the Fc γ receptor IIIb/CD16b structure upon binding immunoglobulin G1 and reduces affinity relative to CD16a