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Brasino M, Wagnell E, Hamilton S, Ranganathan S, Gomes MM, Branchaud B, Messmer B, Ibsen SD. Turning antibodies off and on again using a covalently tethered blocking peptide. Commun Biol 2022; 5:1357. [PMID: 36496512 PMCID: PMC9741643 DOI: 10.1038/s42003-022-04094-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/11/2022] [Indexed: 12/13/2022] Open
Abstract
In their natural form, antibodies are always in an "on-state" and are capable of binding to their targets. This leads to undesirable interactions in a wide range of therapeutic, analytical, and synthetic applications. Modulating binding kinetics of antibodies to turn them from an "off-state" to an "on-state" with temporal and spatial control can address this. Here we demonstrate a method to modulate binding activity of antibodies in a predictable and reproducible way. We designed a blocking construct that uses both covalent and non-covalent interactions with the antibody. The construct consisted of a Protein L protein attached to a flexible linker ending in a blocking-peptide designed to interact with the antibody binding site. A mutant Protein L was developed to enable photo-triggered covalent crosslinking to the antibody at a specific location. The covalent bond anchored the linker and blocking peptide to the antibody light chain keeping the blocking peptide close to the antibody binding site. This effectively put the antibody into an "off-state". We demonstrate that protease-cleavable and photocleavable moieties in the tether enable controlled antibody activation to the "on-state" for anti-FLAG and cetuximab antibodies. Protein L can bind a range of antibodies used therapeutically and in research for wide applicability.
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Affiliation(s)
- Michael Brasino
- grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97201 USA
| | - Eli Wagnell
- grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97201 USA
| | - Sean Hamilton
- grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97201 USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, OR 97201 USA
| | - Srivathsan Ranganathan
- grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97201 USA
| | - Michelle M. Gomes
- grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97201 USA
| | - Bruce Branchaud
- grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97201 USA
| | | | - Stuart D. Ibsen
- grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center, Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97201 USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, School of Medicine, Oregon Health and Science University, Portland, OR 97201 USA
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Paloni M, Cavallotti C. Molecular Modeling of the Interaction of Protein L with Antibodies. ACS OMEGA 2017; 2:6464-6472. [PMID: 31457247 PMCID: PMC6645367 DOI: 10.1021/acsomega.7b01123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 09/27/2017] [Indexed: 06/10/2023]
Abstract
Protein L (PpL) is a bacterial protein which is used in the affinity chromatography stage of the production of monoclonal antibodies because of its ability to form high affinity complexes with the light chains of immunoglobulins. In the present work, the binding interfaces between one domain of PpL and antigen-binding fragments (Fab) have been investigated adopting molecular dynamics with the aim of determining the binding contribution of the residues located at the Fab-PpL interface. Because it is known that PpL binds antibodies through two distinct binding sites with different affinities, simulations were performed for both sites to determine interaction free energies to assess the relative binding contribution of the two sites. Mutational studies were then performed only on the dominant binding site. The binding free energy was evaluated with the molecular mechanics Poisson-Boltzmann surface area (MMPBSA) and umbrella sampling/weighted histogram analysis methods. Key residues for the formation of the dominant binding site complex were identified by means of alanine scanning performed both for the Fab and PpL domains. Residues of the light chain of the antibody that contribute most to binding were found to be located between SER7 and VAL13. Four residues from PpL are important for the stability of the complex: PHE839, LYS840, GLU849, and TYR853. Three residues of PpL that do not contribute to the interaction were mutated to histidine (HIS), which changes its protonation state as a function of pH, to find whether this could allow us to control the binding interaction energy. This can be useful in the elution stage of the affinity chromatography purification of antibodies if PpL is used as a ligand. These residues are GLN835, THR836, and ALA837. Molecular dynamics simulations with both protonated and unprotonated HIS were performed to mimic how changing pH may reflect on protein-ligand interaction energies. The MMPBSA approach was used to evaluate the variation of the affinity of the mutated systems with reference to the wild type. Our results show that these mutations could help in disrupting the complex under acidic conditions without impairing the affinity of PpL for the light chains at higher pHs.
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Abstract
While antibody-based therapeutics have become firmly established as front-line drugs, the use of antibodies as research tools in small molecule drug discovery is still in its infancy. In this review we focus on the use of antibody fragments as crystallization chaperones to aid the structural determination of otherwise 'uncrystallizable' or 'undruggable' target proteins. We also highlight a potential application for this technology, in which antibody-mediated structures may be used to inform the design of new chemical entities.
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Affiliation(s)
- L Griffin
- Department of Structural Biology, UCB, Slough, UK
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Su HP, Golden JW, Gittis AG, Hooper JW, Garboczi DN. Structural basis for the binding of the neutralizing antibody, 7D11, to the poxvirus L1 protein. Virology 2007; 368:331-41. [PMID: 17688903 PMCID: PMC2100026 DOI: 10.1016/j.virol.2007.06.042] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Revised: 06/04/2007] [Accepted: 06/27/2007] [Indexed: 01/07/2023]
Abstract
Medical countermeasures to prevent or treat smallpox are needed due to the potential use of poxviruses as biological weapons. Safety concerns with the currently available smallpox vaccine indicate a need for research on alternative poxvirus vaccine strategies. Molecular vaccines involving the use of proteins and/or genes and recombinant antibodies are among the strategies under current investigation. The poxvirus L1 protein, encoded by the L1R open reading frame, is the target of neutralizing antibodies and has been successfully used as a component of both protein subunit and DNA vaccines. L1-specific monoclonal antibodies (e.g., mouse monoclonal antibody mAb-7D11, mAb-10F5) with potent neutralizing activity bind L1 in a conformation-specific manner. This suggests that proper folding of the L1 protein used in molecular vaccines will affect the production of neutralizing antibodies and protection. Here, we co-crystallized the Fab fragment of mAb-7D11 with the L1 protein. The crystal structure of the complex between Fab-7D11 and L1 reveals the basis for the conformation-specific binding as recognition of a discontinuous epitope containing two loops that are held together by a disulfide bond. The structure of this important conformational epitope of L1 will contribute to the development of molecular poxvirus vaccines and also provides a novel target for anti-poxvirus drugs. In addition, the sequence and structure of Fab-7D11 will contribute to the development of L1-targeted immunotherapeutics.
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Affiliation(s)
- Hua-Poo Su
- Structural Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD 20852, USA
| | - Joseph W. Golden
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702
| | - Apostolos G. Gittis
- Structural Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD 20852, USA
| | - Jay W. Hooper
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702
| | - David N. Garboczi
- Structural Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD 20852, USA
- *Corresponding author. Mailing address. 12441 Parklawn Drive, Rockville, Maryland 20852, USA. Phone: 301-496-4773. Fax: 301-402-0284. E-mail:
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