Bivalent antibody pliers inhibit β-tryptase by an allosteric mechanism dependent on the IgG hinge
Open Access
- 22 December 2020
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature Communications
- Vol. 11 (1), 1-12
- https://doi.org/10.1038/s41467-020-20143-x
Abstract
Human beta -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 beta -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 beta -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 beta -tryptase monomers, and may provide an alternative strategy for antibody engineering. beta -tryptases are responsible for most of the proteolytic activity during mast cell activation. Here, the authors develop beta -tryptase-inhibiting antibodies and provide structural and biochemical evidence that the bivalency of the antibodies is a prerequisite for their inhibitory activity.This publication has 60 references indexed in Scilit:
- RELION: Implementation of a Bayesian approach to cryo-EM structure determinationJournal of Structural Biology, 2012
- Antigen–antibody interface properties: Composition, residue interactions, and features of 53 non-redundant structuresBiochimica et Biophysica Acta (BBA) - Proteins and Proteomics, 2012
- ExMS: Data Analysis for HX-MS ExperimentsJournal of the American Society for Mass Spectrometry, 2011
- Many Overlapping Peptides for Protein Hydrogen Exchange Experiments by the Fragment Separation-Mass Spectrometry MethodJournal of the American Society for Mass Spectrometry, 2011
- A New Clustering of Antibody CDR Loop ConformationsJournal of Molecular Biology, 2011
- Structural insight into distinct mechanisms of protease inhibition by antibodiesProceedings of the National Academy of Sciences of the United States of America, 2007
- The Mechanism of Inhibition of Antibody-based Inhibitors of Membrane-type Serine Protease 1 (MT-SP1)Journal of Molecular Biology, 2007
- EMAN2: An extensible image processing suite for electron microscopyJournal of Structural Biology, 2007
- UCSF Chimera?A visualization system for exploratory research and analysisJournal of Computational Chemistry, 2004
- A New Generation of the IMAGIC Image Processing SystemJournal of Structural Biology, 1996