Molecular recognition requires dimerization of a VHH antibody

Camelid heavy-chain-only antibodies are a unique class of antibody that possesses only a single variable domain (termed VHH) for antigen recognition. Despite their apparent canonical mechanism of target recognition, where a single VHH domain binds a single target, an anti-caffeine VHH has been obser...

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Main Authors: Christopher A. Smith, Gregory J. Sonneson, Robert J. Hoey, Jennifer M. Hinerman, Kimberly Sheehy, Richard Walter, Andrew B. Herr, James R. Horn
Format: Article
Language:English
Published: Taylor & Francis Group 2023-12-01
Series:mAbs
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Online Access:https://www.tandfonline.com/doi/10.1080/19420862.2023.2215363
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author Christopher A. Smith
Gregory J. Sonneson
Robert J. Hoey
Jennifer M. Hinerman
Kimberly Sheehy
Richard Walter
Andrew B. Herr
James R. Horn
author_facet Christopher A. Smith
Gregory J. Sonneson
Robert J. Hoey
Jennifer M. Hinerman
Kimberly Sheehy
Richard Walter
Andrew B. Herr
James R. Horn
author_sort Christopher A. Smith
collection DOAJ
description Camelid heavy-chain-only antibodies are a unique class of antibody that possesses only a single variable domain (termed VHH) for antigen recognition. Despite their apparent canonical mechanism of target recognition, where a single VHH domain binds a single target, an anti-caffeine VHH has been observed to possess 2:1 stoichiometry. Here, the structure of the anti-caffeine VHH/caffeine complex enabled the generation and biophysical analysis of variants that were used to better understand the role of VHH homodimerization in caffeine recognition. VHH interface mutants and caffeine analogs, which were examined to probe the mechanism of caffeine binding, suggested caffeine recognition is only possible with the VHH dimer species. Correspondingly, in the absence of caffeine, the anti-caffeine VHH was found to form a dimer with a dimerization constant comparable to that observed with VH:VL domains in conventional antibody systems, which was most stable near physiological temperature. While the VHH:VHH dimer structure (at 1.13 Å resolution) is reminiscent of conventional VH:VL heterodimers, the homodimeric VHH possesses a smaller angle of domain interaction, as well as a larger amount of apolar surface area burial. To test the general hypothesis that the short complementarity-determining region-3 (CDR3) may help drive VHH:VHH homodimerization, an anti-picloram VHH domain containing a short CDR3 was generated and characterized, which revealed it also existed as dimer species in solution. These results suggest homodimer-driven recognition may represent a more common method of VHH ligand recognition, opening opportunities for novel VHH homodimer affinity reagents and helping to guide their use in chemically induced dimerization applications.
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spelling doaj-art-dcf8946445c34a6d860dc157fbf36be22025-08-20T03:25:59ZengTaylor & Francis GroupmAbs1942-08621942-08702023-12-0115110.1080/19420862.2023.2215363Molecular recognition requires dimerization of a VHH antibodyChristopher A. Smith0Gregory J. Sonneson1Robert J. Hoey2Jennifer M. Hinerman3Kimberly Sheehy4Richard Walter5Andrew B. Herr6James R. Horn7Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, USADepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, USADepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, USADivision of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH USADepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, USAShamrock Structures, LLC, Woodridge, IL, USADivision of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH USADepartment of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL, USACamelid heavy-chain-only antibodies are a unique class of antibody that possesses only a single variable domain (termed VHH) for antigen recognition. Despite their apparent canonical mechanism of target recognition, where a single VHH domain binds a single target, an anti-caffeine VHH has been observed to possess 2:1 stoichiometry. Here, the structure of the anti-caffeine VHH/caffeine complex enabled the generation and biophysical analysis of variants that were used to better understand the role of VHH homodimerization in caffeine recognition. VHH interface mutants and caffeine analogs, which were examined to probe the mechanism of caffeine binding, suggested caffeine recognition is only possible with the VHH dimer species. Correspondingly, in the absence of caffeine, the anti-caffeine VHH was found to form a dimer with a dimerization constant comparable to that observed with VH:VL domains in conventional antibody systems, which was most stable near physiological temperature. While the VHH:VHH dimer structure (at 1.13 Å resolution) is reminiscent of conventional VH:VL heterodimers, the homodimeric VHH possesses a smaller angle of domain interaction, as well as a larger amount of apolar surface area burial. To test the general hypothesis that the short complementarity-determining region-3 (CDR3) may help drive VHH:VHH homodimerization, an anti-picloram VHH domain containing a short CDR3 was generated and characterized, which revealed it also existed as dimer species in solution. These results suggest homodimer-driven recognition may represent a more common method of VHH ligand recognition, opening opportunities for novel VHH homodimer affinity reagents and helping to guide their use in chemically induced dimerization applications.https://www.tandfonline.com/doi/10.1080/19420862.2023.2215363Camelid antibodychemically induced dimerization (CID) systemscrystal structuredimerizationhapten recognitionITC
spellingShingle Christopher A. Smith
Gregory J. Sonneson
Robert J. Hoey
Jennifer M. Hinerman
Kimberly Sheehy
Richard Walter
Andrew B. Herr
James R. Horn
Molecular recognition requires dimerization of a VHH antibody
mAbs
Camelid antibody
chemically induced dimerization (CID) systems
crystal structure
dimerization
hapten recognition
ITC
title Molecular recognition requires dimerization of a VHH antibody
title_full Molecular recognition requires dimerization of a VHH antibody
title_fullStr Molecular recognition requires dimerization of a VHH antibody
title_full_unstemmed Molecular recognition requires dimerization of a VHH antibody
title_short Molecular recognition requires dimerization of a VHH antibody
title_sort molecular recognition requires dimerization of a vhh antibody
topic Camelid antibody
chemically induced dimerization (CID) systems
crystal structure
dimerization
hapten recognition
ITC
url https://www.tandfonline.com/doi/10.1080/19420862.2023.2215363
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