5BW7

Crystal structure of nonfucosylated Fc Y296W mutant complexed with bis-glycosylated soluble form of Fc gamma receptor IIIa

5BW7 の概要

• エントリーDOI: 10.2210/pdb5bw7/pdb
• 分子名称: Ig gamma-1 chain C region, Low affinity immunoglobulin gamma Fc region receptor III-A, beta-D-galactopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-6)-[2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-3)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (8 entities in total)
• 機能のキーワード: immune system, complex, fc fragment, igg, receptor, cd16, gamma
• 由来する生物種: Homo sapiens (Human); 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 75925.99

構造登録者

Isoda, Y.,Yagi, H.,Satoh, T.,Shibata-Koyama, M.,Masuda, K.,Satoh, M.,Kato, K.,Iida, S. (登録日: 2015-06-06, 公開日: 2015-10-14, 最終更新日: 2024-11-06)

主引用文献

Isoda, Y.,Yagi, H.,Satoh, T.,Shibata-Koyama, M.,Masuda, K.,Satoh, M.,Kato, K.,Iida, S.
Importance of the Side Chain at Position 296 of Antibody Fc in Interactions with Fc gamma RIIIa and Other Fc gamma Receptors
Plos One, 10:e0140120-e0140120, 2015

PubMed Abstract: Antibody-dependent cellular cytotoxicity (ADCC) is an important effector function determining the clinical efficacy of therapeutic antibodies. Core fucose removal from N-glycans on the Fc portion of immunoglobulin G (IgG) improves the binding affinity for Fcγ receptor IIIa (FcγRIIIa) and dramatically enhances ADCC. Our previous structural analyses revealed that Tyr-296 of IgG1-Fc plays a critical role in the interaction with FcγRIIIa, particularly in the enhanced FcγRIIIa binding of nonfucosylated IgG1. However, the importance of the Tyr-296 residue in the antibody in the interaction with various Fcγ receptors has not yet been elucidated. To further clarify the biological importance of this residue, we established comprehensive Tyr-296 mutants as fucosylated and nonfucosylated anti-CD20 IgG1s rituximab variants and examined their binding to recombinant soluble human Fcγ receptors: shFcγRI, shFcγRIIa, shFcγRIIIa, and shFcγRIIIb. Some of the mutations affected the binding of antibody to not only shFcγRIIIa but also shFcγRIIa and shFcγRIIIb, suggesting that the Tyr-296 residue in the antibody was also involved in interactions with FcγRIIa and FcγRIIIb. For FcγRIIIa binding, almost all Tyr-296 variants showed lower binding affinities than the wild-type antibody, irrespective of their core fucosylation, particularly in Y296K and Y296P. Notably, only the Y296W mutant showed improved binding to FcγRIIIa. The 3.00 Å-resolution crystal structure of the nonfucosylated Y296W mutant in complex with shFcγRIIIa harboring two N-glycans revealed that the Tyr-to-Trp substitution increased the number of potential contact atoms in the complex, thus improving the binding of the antibody to shFcγRIIIa. The nonfucosylated Y296W mutant retained high ADCC activity, relative to the nonfucosylated wild-type IgG1, and showed greater binding affinity for FcγRIIa. Our data may improve our understanding of the biological importance of human IgG1-Fc Tyr-296 in interactions with various Fcγ receptors, and have applications in the modulation of the IgG1-Fc function of therapeutic antibodies.

PubMed: 26444434
DOI: 10.1371/journal.pone.0140120

実験手法

X-RAY DIFFRACTION (3 Å)