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Structural Basis for the Activation of Platelet Integrin αIIbβ3 by Calcium- and Integrin-Binding Protein 1

[Image: see text] Calcium and integrin binding protein 1 (CIB1) is a specific binding partner for the cytoplasmic domain of the αIIb subunit of the highly abundant platelet integrin αIIbβ3. This protein has been suggested to be involved in the regulation of the activation of αIIbβ3, a process leadin...

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Autores principales: Huang, Hao, Vogel, Hans J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2012
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3290099/
https://www.ncbi.nlm.nih.gov/pubmed/22283712
http://dx.doi.org/10.1021/ja2111306
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author Huang, Hao
Vogel, Hans J.
author_facet Huang, Hao
Vogel, Hans J.
author_sort Huang, Hao
collection PubMed
description [Image: see text] Calcium and integrin binding protein 1 (CIB1) is a specific binding partner for the cytoplasmic domain of the αIIb subunit of the highly abundant platelet integrin αIIbβ3. This protein has been suggested to be involved in the regulation of the activation of αIIbβ3, a process leading to platelet aggregation and blood coagulation. In this work, the solution structure of the deuterated Ca(2+)-CIB1 protein complexed with an αIIb peptide was first determined through modern RDC-based NMR methods. Next, we generated a complex structure for CIB1 and the αIIb domain (Ca(2+)-CIB1/αIIb) using the program Haddock, which is based on experimental restraints obtained for the protein–peptide interface from cross-saturation NMR experiments. In this data-driven complex structure, the N-terminal α-helix of the cytoplasmic domain of αIIb is buried in the hydrophobic pocket of the C-lobe of Ca(2+)-CIB1. The C-terminal acidic tail of αIIb remains unstructured and likely interacts with several positively charged residues in the N-lobe of Ca(2+)-CIB1. A potential molecular mechanism for the CIB1-mediated activation of the platelet integrin could be proposed on the basis of the model structure of this protein complex. Another feature of this work is that, in the NMR cross-saturation experiments, we applied the selective radio frequency irradiation to the smaller binding partner (the αIIb peptide), and successfully detected the binding interface on the larger binding partner Ca(2+)-CIB1 through its selectively protonated methyl groups. This ‘reverse’ methodology has a broad potential to be employed to many other complexes where synthetic peptides and a suitably isotope-labeled medium- to large-sized protein are used to study protein–protein interactions.
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spelling pubmed-32900992012-02-29 Structural Basis for the Activation of Platelet Integrin αIIbβ3 by Calcium- and Integrin-Binding Protein 1 Huang, Hao Vogel, Hans J. J Am Chem Soc [Image: see text] Calcium and integrin binding protein 1 (CIB1) is a specific binding partner for the cytoplasmic domain of the αIIb subunit of the highly abundant platelet integrin αIIbβ3. This protein has been suggested to be involved in the regulation of the activation of αIIbβ3, a process leading to platelet aggregation and blood coagulation. In this work, the solution structure of the deuterated Ca(2+)-CIB1 protein complexed with an αIIb peptide was first determined through modern RDC-based NMR methods. Next, we generated a complex structure for CIB1 and the αIIb domain (Ca(2+)-CIB1/αIIb) using the program Haddock, which is based on experimental restraints obtained for the protein–peptide interface from cross-saturation NMR experiments. In this data-driven complex structure, the N-terminal α-helix of the cytoplasmic domain of αIIb is buried in the hydrophobic pocket of the C-lobe of Ca(2+)-CIB1. The C-terminal acidic tail of αIIb remains unstructured and likely interacts with several positively charged residues in the N-lobe of Ca(2+)-CIB1. A potential molecular mechanism for the CIB1-mediated activation of the platelet integrin could be proposed on the basis of the model structure of this protein complex. Another feature of this work is that, in the NMR cross-saturation experiments, we applied the selective radio frequency irradiation to the smaller binding partner (the αIIb peptide), and successfully detected the binding interface on the larger binding partner Ca(2+)-CIB1 through its selectively protonated methyl groups. This ‘reverse’ methodology has a broad potential to be employed to many other complexes where synthetic peptides and a suitably isotope-labeled medium- to large-sized protein are used to study protein–protein interactions. American Chemical Society 2012-01-27 2012-02-29 /pmc/articles/PMC3290099/ /pubmed/22283712 http://dx.doi.org/10.1021/ja2111306 Text en Copyright © 2012 American Chemical Society http://pubs.acs.org This is an open-access article distributed under the ACS AuthorChoice Terms & Conditions. Any use of this article, must conform to the terms of that license which are available at http://pubs.acs.org.
spellingShingle Huang, Hao
Vogel, Hans J.
Structural Basis for the Activation of Platelet Integrin αIIbβ3 by Calcium- and Integrin-Binding Protein 1
title Structural Basis for the Activation of Platelet Integrin αIIbβ3 by Calcium- and Integrin-Binding Protein 1
title_full Structural Basis for the Activation of Platelet Integrin αIIbβ3 by Calcium- and Integrin-Binding Protein 1
title_fullStr Structural Basis for the Activation of Platelet Integrin αIIbβ3 by Calcium- and Integrin-Binding Protein 1
title_full_unstemmed Structural Basis for the Activation of Platelet Integrin αIIbβ3 by Calcium- and Integrin-Binding Protein 1
title_short Structural Basis for the Activation of Platelet Integrin αIIbβ3 by Calcium- and Integrin-Binding Protein 1
title_sort structural basis for the activation of platelet integrin αiibβ3 by calcium- and integrin-binding protein 1
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3290099/
https://www.ncbi.nlm.nih.gov/pubmed/22283712
http://dx.doi.org/10.1021/ja2111306
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