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Structural Ensemble of the Insulin Monomer

[Image: see text] Experimental evidence suggests that monomeric insulin exhibits significant conformational heterogeneity, and modifications of apparently disordered regions affect both biological activity and the longevity of pharmaceutical formulations, presumably through receptor binding and fibr...

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Autores principales: Busto-Moner, Luis, Feng, Chi-Jui, Antoszewski, Adam, Tokmakoff, Andrei, Dinner, Aaron R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2021
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8552439/
https://www.ncbi.nlm.nih.gov/pubmed/34637307
http://dx.doi.org/10.1021/acs.biochem.1c00583
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author Busto-Moner, Luis
Feng, Chi-Jui
Antoszewski, Adam
Tokmakoff, Andrei
Dinner, Aaron R.
author_facet Busto-Moner, Luis
Feng, Chi-Jui
Antoszewski, Adam
Tokmakoff, Andrei
Dinner, Aaron R.
author_sort Busto-Moner, Luis
collection PubMed
description [Image: see text] Experimental evidence suggests that monomeric insulin exhibits significant conformational heterogeneity, and modifications of apparently disordered regions affect both biological activity and the longevity of pharmaceutical formulations, presumably through receptor binding and fibrillation/degradation, respectively. However, a microscopic understanding of conformational heterogeneity has been lacking. Here, we integrate all-atom molecular dynamics simulations with an analysis pipeline to investigate the structural ensemble of human insulin monomers. We find that 60% of the structures present at least one of the following elements of disorder: melting of the A-chain N-terminal helix, detachment of the B-chain N-terminus, and detachment of the B-chain C-terminus. We also observe partial melting and extension of the B-chain helix and significant conformational heterogeneity in the region containing the B-chain β-turn. We then estimate hydrogen-exchange protection factors for the sampled ensemble and find them in line with experimental results for KP-insulin, although the simulations underestimate the importance of unfolded states. Our results help explain the ready exchange of specific amide sites that appear to be protected in crystal structures. Finally, we discuss the implications for insulin function and stability.
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spelling pubmed-85524392021-10-29 Structural Ensemble of the Insulin Monomer Busto-Moner, Luis Feng, Chi-Jui Antoszewski, Adam Tokmakoff, Andrei Dinner, Aaron R. Biochemistry [Image: see text] Experimental evidence suggests that monomeric insulin exhibits significant conformational heterogeneity, and modifications of apparently disordered regions affect both biological activity and the longevity of pharmaceutical formulations, presumably through receptor binding and fibrillation/degradation, respectively. However, a microscopic understanding of conformational heterogeneity has been lacking. Here, we integrate all-atom molecular dynamics simulations with an analysis pipeline to investigate the structural ensemble of human insulin monomers. We find that 60% of the structures present at least one of the following elements of disorder: melting of the A-chain N-terminal helix, detachment of the B-chain N-terminus, and detachment of the B-chain C-terminus. We also observe partial melting and extension of the B-chain helix and significant conformational heterogeneity in the region containing the B-chain β-turn. We then estimate hydrogen-exchange protection factors for the sampled ensemble and find them in line with experimental results for KP-insulin, although the simulations underestimate the importance of unfolded states. Our results help explain the ready exchange of specific amide sites that appear to be protected in crystal structures. Finally, we discuss the implications for insulin function and stability. American Chemical Society 2021-10-12 2021-10-26 /pmc/articles/PMC8552439/ /pubmed/34637307 http://dx.doi.org/10.1021/acs.biochem.1c00583 Text en © 2021 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Busto-Moner, Luis
Feng, Chi-Jui
Antoszewski, Adam
Tokmakoff, Andrei
Dinner, Aaron R.
Structural Ensemble of the Insulin Monomer
title Structural Ensemble of the Insulin Monomer
title_full Structural Ensemble of the Insulin Monomer
title_fullStr Structural Ensemble of the Insulin Monomer
title_full_unstemmed Structural Ensemble of the Insulin Monomer
title_short Structural Ensemble of the Insulin Monomer
title_sort structural ensemble of the insulin monomer
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8552439/
https://www.ncbi.nlm.nih.gov/pubmed/34637307
http://dx.doi.org/10.1021/acs.biochem.1c00583
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