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NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein

Antifreeze protein (AFP) has a unique function of reducing solution freezing temperature to protect organisms from ice damage. However, its functional mechanism is not well understood. An intriguing question concerning AFP function is how the high selectivity for ice ligand is achieved in the presen...

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Autores principales: Hong, Jiang, Hu, Yunfei, Li, Congmin, Jia, Zongchao, Xia, Bin, Jin, Changwen
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3011014/
https://www.ncbi.nlm.nih.gov/pubmed/21209943
http://dx.doi.org/10.1371/journal.pone.0015682
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author Hong, Jiang
Hu, Yunfei
Li, Congmin
Jia, Zongchao
Xia, Bin
Jin, Changwen
author_facet Hong, Jiang
Hu, Yunfei
Li, Congmin
Jia, Zongchao
Xia, Bin
Jin, Changwen
author_sort Hong, Jiang
collection PubMed
description Antifreeze protein (AFP) has a unique function of reducing solution freezing temperature to protect organisms from ice damage. However, its functional mechanism is not well understood. An intriguing question concerning AFP function is how the high selectivity for ice ligand is achieved in the presence of free water of much higher concentration which likely imposes a large kinetic barrier for protein-ice recognition. In this study, we explore this question by investigating the property of the ice binding surface of an antifreeze protein using NMR spectroscopy. An investigation of the temperature gradient of amide proton chemical shift and its correlation with chemical shift deviation from random coil was performed for CfAFP-501, a hyperactive insect AFP. A good correlation between the two parameters was observed for one of the two Thr rows on the ice binding surface. A significant temperature-dependent protein-solvent interaction is found to be the most probable origin for this correlation, which is consistent with a scenario of hydrophobic hydration on the ice binding surface. In accordance with this finding, rotational correlation time analyses combined with relaxation dispersion measurements reveals a weak dimer formation through ice binding surface at room temperature and a population shift of dimer to monomer at low temperature, suggesting hydrophobic effect involved in dimer formation and hence hydrophobic hydration on the ice binding surface of the protein. Our finding of hydrophobic hydration on the ice binding surface provides a test for existing simulation studies. The occurrence of hydrophobic hydration on the ice binding surface is likely unnecessary for enhancing protein-ice binding affinity which is achieved by a tight H-bonding network. Subsequently, we speculate that the hydrophobic hydration occurring on the ice binding surface plays a role in facilitating protein-ice recognition by lowering the kinetic barrier as suggested by some simulation studies.
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spelling pubmed-30110142011-01-05 NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein Hong, Jiang Hu, Yunfei Li, Congmin Jia, Zongchao Xia, Bin Jin, Changwen PLoS One Research Article Antifreeze protein (AFP) has a unique function of reducing solution freezing temperature to protect organisms from ice damage. However, its functional mechanism is not well understood. An intriguing question concerning AFP function is how the high selectivity for ice ligand is achieved in the presence of free water of much higher concentration which likely imposes a large kinetic barrier for protein-ice recognition. In this study, we explore this question by investigating the property of the ice binding surface of an antifreeze protein using NMR spectroscopy. An investigation of the temperature gradient of amide proton chemical shift and its correlation with chemical shift deviation from random coil was performed for CfAFP-501, a hyperactive insect AFP. A good correlation between the two parameters was observed for one of the two Thr rows on the ice binding surface. A significant temperature-dependent protein-solvent interaction is found to be the most probable origin for this correlation, which is consistent with a scenario of hydrophobic hydration on the ice binding surface. In accordance with this finding, rotational correlation time analyses combined with relaxation dispersion measurements reveals a weak dimer formation through ice binding surface at room temperature and a population shift of dimer to monomer at low temperature, suggesting hydrophobic effect involved in dimer formation and hence hydrophobic hydration on the ice binding surface of the protein. Our finding of hydrophobic hydration on the ice binding surface provides a test for existing simulation studies. The occurrence of hydrophobic hydration on the ice binding surface is likely unnecessary for enhancing protein-ice binding affinity which is achieved by a tight H-bonding network. Subsequently, we speculate that the hydrophobic hydration occurring on the ice binding surface plays a role in facilitating protein-ice recognition by lowering the kinetic barrier as suggested by some simulation studies. Public Library of Science 2010-12-28 /pmc/articles/PMC3011014/ /pubmed/21209943 http://dx.doi.org/10.1371/journal.pone.0015682 Text en Hong et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Hong, Jiang
Hu, Yunfei
Li, Congmin
Jia, Zongchao
Xia, Bin
Jin, Changwen
NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein
title NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein
title_full NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein
title_fullStr NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein
title_full_unstemmed NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein
title_short NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein
title_sort nmr characterizations of the ice binding surface of an antifreeze protein
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3011014/
https://www.ncbi.nlm.nih.gov/pubmed/21209943
http://dx.doi.org/10.1371/journal.pone.0015682
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