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Avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site

Although myriad protein–protein interactions in nature use polyvalent binding, in which multiple ligands on one entity bind to multiple receptors on another, to date an affinity advantage of polyvalent binding has been demonstrated experimentally only in cases where the target receptor molecules are...

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Autores principales: Lacham-Hartman, Shiran, Shmidov, Yulia, Radisky, Evette S., Bitton, Ronit, Lukatsky, David B., Papo, Niv
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8631645/
https://www.ncbi.nlm.nih.gov/pubmed/34847142
http://dx.doi.org/10.1371/journal.pone.0249616
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author Lacham-Hartman, Shiran
Shmidov, Yulia
Radisky, Evette S.
Bitton, Ronit
Lukatsky, David B.
Papo, Niv
author_facet Lacham-Hartman, Shiran
Shmidov, Yulia
Radisky, Evette S.
Bitton, Ronit
Lukatsky, David B.
Papo, Niv
author_sort Lacham-Hartman, Shiran
collection PubMed
description Although myriad protein–protein interactions in nature use polyvalent binding, in which multiple ligands on one entity bind to multiple receptors on another, to date an affinity advantage of polyvalent binding has been demonstrated experimentally only in cases where the target receptor molecules are clustered prior to complex formation. Here, we demonstrate cooperativity in binding affinity (i.e., avidity) for a protein complex in which an engineered dimer of the amyloid precursor protein inhibitor (APPI), possessing two fully functional inhibitory loops, interacts with mesotrypsin, a soluble monomeric protein that does not self-associate or cluster spontaneously. We found that each inhibitory loop of the purified APPI homodimer was over three-fold more potent than the corresponding loop in the monovalent APPI inhibitor. This observation is consistent with a suggested mechanism whereby the two APPI loops in the homodimer simultaneously and reversibly bind two corresponding mesotrypsin monomers to mediate mesotrypsin dimerization. We propose a simple model for such dimerization that quantitatively explains the observed cooperativity in binding affinity. Binding cooperativity in this system reveals that the valency of ligands may affect avidity in protein–protein interactions including those of targets that are not surface-anchored and do not self-associate spontaneously. In this scenario, avidity may be explained by the enhanced concentration of ligand binding sites in proximity to the monomeric target, which may favor rebinding of the multiple ligand binding sites with the receptor molecules upon dissociation of the protein complex.
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spelling pubmed-86316452021-12-01 Avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site Lacham-Hartman, Shiran Shmidov, Yulia Radisky, Evette S. Bitton, Ronit Lukatsky, David B. Papo, Niv PLoS One Research Article Although myriad protein–protein interactions in nature use polyvalent binding, in which multiple ligands on one entity bind to multiple receptors on another, to date an affinity advantage of polyvalent binding has been demonstrated experimentally only in cases where the target receptor molecules are clustered prior to complex formation. Here, we demonstrate cooperativity in binding affinity (i.e., avidity) for a protein complex in which an engineered dimer of the amyloid precursor protein inhibitor (APPI), possessing two fully functional inhibitory loops, interacts with mesotrypsin, a soluble monomeric protein that does not self-associate or cluster spontaneously. We found that each inhibitory loop of the purified APPI homodimer was over three-fold more potent than the corresponding loop in the monovalent APPI inhibitor. This observation is consistent with a suggested mechanism whereby the two APPI loops in the homodimer simultaneously and reversibly bind two corresponding mesotrypsin monomers to mediate mesotrypsin dimerization. We propose a simple model for such dimerization that quantitatively explains the observed cooperativity in binding affinity. Binding cooperativity in this system reveals that the valency of ligands may affect avidity in protein–protein interactions including those of targets that are not surface-anchored and do not self-associate spontaneously. In this scenario, avidity may be explained by the enhanced concentration of ligand binding sites in proximity to the monomeric target, which may favor rebinding of the multiple ligand binding sites with the receptor molecules upon dissociation of the protein complex. Public Library of Science 2021-11-30 /pmc/articles/PMC8631645/ /pubmed/34847142 http://dx.doi.org/10.1371/journal.pone.0249616 Text en © 2021 Lacham-Hartman et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Lacham-Hartman, Shiran
Shmidov, Yulia
Radisky, Evette S.
Bitton, Ronit
Lukatsky, David B.
Papo, Niv
Avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site
title Avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site
title_full Avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site
title_fullStr Avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site
title_full_unstemmed Avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site
title_short Avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site
title_sort avidity observed between a bivalent inhibitor and an enzyme monomer with a single active site
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8631645/
https://www.ncbi.nlm.nih.gov/pubmed/34847142
http://dx.doi.org/10.1371/journal.pone.0249616
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