ジャーナル: Nat Commun / 年: 2020 タイトル: Bivalent antibody pliers inhibit β-tryptase by an allosteric mechanism dependent on the IgG hinge. 著者: Henry R Maun / Rajesh Vij / Benjamin T Walters / Ashley Morando / Janet K Jackman / Ping Wu / Alberto Estevez / Xiaocheng Chen / Yvonne Franke / Michael T Lipari / Mark S Dennis / Daniel ...著者: Henry R Maun / Rajesh Vij / Benjamin T Walters / Ashley Morando / Janet K Jackman / Ping Wu / Alberto Estevez / Xiaocheng Chen / Yvonne Franke / Michael T Lipari / Mark S Dennis / Daniel Kirchhofer / Claudio Ciferri / Kelly M Loyet / Tangsheng Yi / Charles Eigenbrot / Robert A Lazarus / James T Koerber / 要旨: Human β-tryptase, a tetrameric trypsin-like serine protease, is an important mediator of allergic inflammatory responses in asthma. Antibodies generally inhibit proteases by blocking substrate ...Human β-tryptase, a tetrameric trypsin-like serine protease, is an important mediator of allergic inflammatory responses in asthma. Antibodies generally inhibit proteases by blocking substrate access by binding to active sites or exosites or by allosteric modulation. The bivalency of IgG antibodies can increase potency via avidity, but has never been described as essential for activity. Here we report an inhibitory anti-tryptase IgG antibody with a bivalency-driven mechanism of action. Using biochemical and structural data, we determine that four Fabs simultaneously occupy four exosites on the β-tryptase tetramer, inducing allosteric changes at the small interface. In the presence of heparin, the monovalent Fab shows essentially no inhibition, whereas the bivalent IgG fully inhibits β-tryptase activity in a hinge-dependent manner. Our results suggest a model where the bivalent IgG acts akin to molecular pliers, pulling the tetramer apart into inactive β-tryptase monomers, and may provide an alternative strategy for antibody engineering.
名称: Tryptase bound to E104 Fab / タイプ: complex / ID: 1 / 親要素: 0
由来(天然)
生物種: Homo sapiens (ヒト)
組換発現
生物種: Escherichia coli (大腸菌)
分子量
実験値: 340 kDa/nm
-
実験情報
-
構造解析
手法
ネガティブ染色法
解析
単粒子再構成法
試料の集合状態
particle
-
試料調製
濃度
0.02 mg/mL
緩衝液
pH: 6.8 / 詳細: 10 mM MOPS pH 6.8, 2 M NaCl
染色
タイプ: NEGATIVE / 材質: Uranyl Formate 詳細: Four microliters of purified beta-tryptase bound to E104.v1 Fab fragment were applied to a freshly glow discharged 400-mesh copper EM grid covered with a thin layer of continuous carbon (Ted ...詳細: Four microliters of purified beta-tryptase bound to E104.v1 Fab fragment were applied to a freshly glow discharged 400-mesh copper EM grid covered with a thin layer of continuous carbon (Ted Pella, Redding, CA). After 30 s of incubation, the grids were stained with 5 drops of a freshly prepared 0.75% (w/v) uranyl formate solution.
グリッド
前処理 - タイプ: GLOW DISCHARGE / 詳細: unspecified
詳細
purified through affinity purification and Size Exclusion Chromatography in 10 mM MOPS pH 6.8, 2 M NaCl.
-
電子顕微鏡法
顕微鏡
FEI TECNAI 12
撮影
フィルム・検出器のモデル: GATAN ULTRASCAN 4000 (4k x 4k) 平均電子線量: 40.0 e/Å2