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Chandler PG, Buckle AM. Development and Differentiation in Monobodies Based on the Fibronectin Type 3 Domain. Cells 2020; 9:E610. [PMID: 32143310 PMCID: PMC7140400 DOI: 10.3390/cells9030610] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/24/2020] [Accepted: 03/01/2020] [Indexed: 12/13/2022] Open
Abstract
As a non-antibody scaffold, monobodies based on the fibronectin type III (FN3) domain overcome antibody size and complexity while maintaining analogous binding loops. However, antibodies and their derivatives remain the gold standard for the design of new therapeutics. In response, clinical-stage therapeutic proteins based on the FN3 domain are beginning to use native fibronectin function as a point of differentiation. The small and simple structure of monomeric monobodies confers increased tissue distribution and reduced half-life, whilst the absence of disulphide bonds improves stability in cytosolic environments. Where multi-specificity is challenging with an antibody format that is prone to mis-pairing between chains, multiple FN3 domains in the fibronectin assembly already interact with a large number of molecules. As such, multiple monobodies engineered for interaction with therapeutic targets are being combined in a similar beads-on-a-string assembly which improves both efficacy and pharmacokinetics. Furthermore, full length fibronectin is able to fold into multiple conformations as part of its natural function and a greater understanding of how mechanical forces allow for the transition between states will lead to advanced applications that truly differentiate the FN3 domain as a therapeutic scaffold.
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Affiliation(s)
- Peter G. Chandler
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton 3800, Australia;
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Stine JM, Ahl GJH, Schlenker C, Rusnac DV, Briknarová K. The Interaction between the Third Type III Domain from Fibronectin and Anastellin Involves β-Strand Exchange. Biochemistry 2017; 56:4667-4675. [PMID: 28820240 DOI: 10.1021/acs.biochem.7b00633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Anastellin is a small recombinant fragment derived from the extracellular matrix protein fibronectin; it comprises the first type III (FN3) domain without the two N-terminal β-strands. It inhibits angiogenesis, tumor growth, and metastasis in mouse models and requires endogenous fibronectin for its in vivo anti-angiogenic activity. It binds to fibronectin in vitro and converts the soluble protein to insoluble fibrils that structurally and functionally resemble fibronectin fibrils deposited in the extracellular matrix by cells. Anastellin binds to several FN3 domains in fibronectin, but how it interacts with these domains and why the interactions lead to aggregation of fibronectin are not well understood. In this work, we investigated the interaction between anastellin and the third FN3 domain (3FN3) from fibronectin. We show that anastellin binds with high affinity to a peptide comprising the two N-terminal β-strands from 3FN3, and we present here the structure of the resulting complex. The peptide and anastellin form a composite FN3 domain, with the two N-terminal β-strands from 3FN3 bound in place of the two β-strands that are missing in anastellin. We also demonstrate using disulfide cross-linking that a similar interaction involving the two N-terminal β-strands of 3FN3 occurs when intact 3FN3 binds to anastellin. 3FN3 adopts a compact globular fold in solution, and to interact with anastellin in a manner consistent with our data, it has to open up and expose a β-strand edge that is not accessible in the context of the folded domain.
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Affiliation(s)
- Jessica M Stine
- Department of Chemistry and Biochemistry, University of Montana , Missoula, Montana 59812, United States
| | - Gabriel J H Ahl
- Department of Chemistry and Biochemistry, University of Montana , Missoula, Montana 59812, United States
| | - Casey Schlenker
- Department of Chemistry and Biochemistry, University of Montana , Missoula, Montana 59812, United States
| | - Domnita-Valeria Rusnac
- Department of Chemistry and Biochemistry, University of Montana , Missoula, Montana 59812, United States
| | - Klára Briknarová
- Department of Chemistry and Biochemistry, University of Montana , Missoula, Montana 59812, United States.,Center for Biomolecular Structure and Dynamics, University of Montana , Missoula, Montana 59812, United States
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Goldberg SD, Cardoso RMF, Lin T, Spinka-Doms T, Klein D, Jacobs SA, Dudkin V, Gilliland G, O'Neil KT. Engineering a targeted delivery platform using Centyrins. Protein Eng Des Sel 2016; 29:563-572. [PMID: 27737926 DOI: 10.1093/protein/gzw054] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 09/20/2016] [Indexed: 12/11/2022] Open
Abstract
Targeted delivery of therapeutic payloads to specific tissues and cell types is an important component of modern pharmaceutical development. Antibodies or other scaffold proteins can provide the cellular address for delivering a covalently linked therapeutic via specific binding to cell-surface receptors. Optimization of the conjugation site on the targeting protein, linker chemistry and intracellular trafficking pathways can all influence the efficiency of delivery and potency of the drug candidate. In this study, we describe a comprehensive engineering experiment for an EGFR binding Centyrin, a highly stable fibronectin type III (FN3) domain, wherein all possible single-cysteine replacements were evaluated for expression, purification, conjugation efficiency, retention of target binding, biophysical properties and delivery of a cytotoxic small molecule payload. Overall, 26 of the 94 positions were identified as ideal for cysteine modification, conjugation and drug delivery. Conjugation-tolerant positions were mapped onto a crystal structure of the Centyrin, providing a structural context for interpretation of the mutagenesis experiment and providing a foundation for a Centyrin-targeted delivery platform.
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Affiliation(s)
- Shalom D Goldberg
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
| | - Rosa M F Cardoso
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
| | - Tricia Lin
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
| | - Tracy Spinka-Doms
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
| | - Donna Klein
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
| | - Steven A Jacobs
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
| | - Vadim Dudkin
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
| | - Gary Gilliland
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
| | - Karyn T O'Neil
- Janssen Research and Development, L.L.C., 1400 McKean Road, Spring House, PA 19477, USA
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Heinzelman P, Krais J, Ruben E, Pantazes R. Engineering pH responsive fibronectin domains for biomedical applications. J Biol Eng 2015; 9:6. [PMID: 26106447 PMCID: PMC4477602 DOI: 10.1186/s13036-015-0004-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/01/2015] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Engineered antibodies with pH responsive cell surface target antigen-binding affinities that decrease at the acidic pH (5.5-5.8) within the endosomes have been found to have reduced susceptibility to degradation within the lysosomes and increased serum half-life. Such pH responsive recombinant antibodies have been developed for the treatment of cancer and cardiovascular disease. Engineered tenth type III human fibronectin (Fn3) domains are emerging as a class of target antigen-binding biopharmaceuticals that could complement or be superior to recombinant antibodies in a number of biomedical contexts. As such, there is strong motivation for demonstrating the feasibility of engineering Fn3s with pH responsive antigen binding behavior that could lead to improved Fn3 pharmacokinetics. RESULTS A yeast surface-displayed Fn3 histidine (His) mutant library screening approach yielded epidermal growth factor receptor (EGFR)-binding Fn3 domains with EGFR binding affinities that markedly decrease at endosomal pH; the first reported case of engineering Fn3s with pH responsive antigen binding. Yeast surface-displayed His mutant Fn3s, which contain either one or two His mutations, have equilibrium binding dissociation constants (KDs) that increase up to four-fold relative to wild type when pH is decreased from 7.4 to 5.5. Assays in which Fn3-displaying yeast were incubated with soluble EGFR after ligand-free incubation in respective neutral and acidic buffers showed that His mutant Fn3 pH responsiveness is due to reversible changes in Fn3 conformation and/or EGFR binding interface properties rather than irreversible unfolding. CONCLUSIONS We have established a generalizable method for efficiently constructing and screening Fn3 His mutant libraries that could enable both our laboratory and others to develop pH responsive Fn3s for use in a wide range of biomedical applications.
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Affiliation(s)
- Pete Heinzelman
- Department of Chemical, Biological & Materials Engineering, University of Oklahoma, Sarkeys Energy Center, 100 East Boyd Street, Room T-301, 73019 Norman, OK USA
| | - John Krais
- Department of Chemical, Biological & Materials Engineering, University of Oklahoma, Sarkeys Energy Center, 100 East Boyd Street, Room T-301, 73019 Norman, OK USA
| | - Eliza Ruben
- Department of Chemistry & Biochemistry, University of Oklahoma, 73019 Norman, OK USA
| | - Robert Pantazes
- Department of Chemical Engineering, University of California-Santa Barbara, 93106 Santa Barbara, CA USA
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