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Hydration Dynamics of Model Peptides with Different Hydrophobic Character
The multi-scale dynamics of aqueous solutions of the hydrophilic peptide N-acetyl-glycine-methylamide (NAGMA) have been investigated through extended frequency-range depolarized light scattering (EDLS), which enables the broad-band detection of collective polarizability anisotropy fluctuations. The...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9031890/ https://www.ncbi.nlm.nih.gov/pubmed/35455063 http://dx.doi.org/10.3390/life12040572 |
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author | Lupi, Laura Bracco, Brenda Sassi, Paola Corezzi, Silvia Morresi, Assunta Fioretto, Daniele Comez, Lucia Paolantoni, Marco |
author_facet | Lupi, Laura Bracco, Brenda Sassi, Paola Corezzi, Silvia Morresi, Assunta Fioretto, Daniele Comez, Lucia Paolantoni, Marco |
author_sort | Lupi, Laura |
collection | PubMed |
description | The multi-scale dynamics of aqueous solutions of the hydrophilic peptide N-acetyl-glycine-methylamide (NAGMA) have been investigated through extended frequency-range depolarized light scattering (EDLS), which enables the broad-band detection of collective polarizability anisotropy fluctuations. The results have been compared to those obtained for N-acetyl-leucinemethylamide (NALMA), an amphiphilic peptide which shares with NAGMA the same polar backbone, but also contains an apolar group. Our study indicates that the two model peptides induce similar effects on the fast translational dynamics of surrounding water. Both systems slow down the mobility of solvating water molecules by a factor 6–8, with respect to the bulk. Moreover, the two peptides cause a comparable far-reaching spatial perturbation extending to more than two hydration layers in diluted conditions. The observed concentration dependence of the hydration number is explained considering the random superposition of different hydration shells, while no indication of solute aggregation phenomena has been found. The results indicate that the effect on the dynamics of water solvating the amphiphilic peptide is dominated by the hydrophilic backbone. The minor impact of the hydrophobic moiety on hydration features is consistent with structural findings derived by Fourier transform infrared (FTIR) measurements, performed in attenuated total reflectance (ATR) configuration. Additionally, we give evidence that, for both systems, the relaxation mode in the GHz frequency range probed by EDLS is related to solute rotational dynamics. The rotation of NALMA occurs at higher timescales, with respect to the rotation of NAGMA; both processes are significantly slower than the structural dynamics of hydration water, suggesting that solute and solvent motions are uncoupled. Finally, our results do not indicate the presence of super-slow water (relaxation times in the order of tens of picoseconds) around the peptides investigated. |
format | Online Article Text |
id | pubmed-9031890 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-90318902022-04-23 Hydration Dynamics of Model Peptides with Different Hydrophobic Character Lupi, Laura Bracco, Brenda Sassi, Paola Corezzi, Silvia Morresi, Assunta Fioretto, Daniele Comez, Lucia Paolantoni, Marco Life (Basel) Article The multi-scale dynamics of aqueous solutions of the hydrophilic peptide N-acetyl-glycine-methylamide (NAGMA) have been investigated through extended frequency-range depolarized light scattering (EDLS), which enables the broad-band detection of collective polarizability anisotropy fluctuations. The results have been compared to those obtained for N-acetyl-leucinemethylamide (NALMA), an amphiphilic peptide which shares with NAGMA the same polar backbone, but also contains an apolar group. Our study indicates that the two model peptides induce similar effects on the fast translational dynamics of surrounding water. Both systems slow down the mobility of solvating water molecules by a factor 6–8, with respect to the bulk. Moreover, the two peptides cause a comparable far-reaching spatial perturbation extending to more than two hydration layers in diluted conditions. The observed concentration dependence of the hydration number is explained considering the random superposition of different hydration shells, while no indication of solute aggregation phenomena has been found. The results indicate that the effect on the dynamics of water solvating the amphiphilic peptide is dominated by the hydrophilic backbone. The minor impact of the hydrophobic moiety on hydration features is consistent with structural findings derived by Fourier transform infrared (FTIR) measurements, performed in attenuated total reflectance (ATR) configuration. Additionally, we give evidence that, for both systems, the relaxation mode in the GHz frequency range probed by EDLS is related to solute rotational dynamics. The rotation of NALMA occurs at higher timescales, with respect to the rotation of NAGMA; both processes are significantly slower than the structural dynamics of hydration water, suggesting that solute and solvent motions are uncoupled. Finally, our results do not indicate the presence of super-slow water (relaxation times in the order of tens of picoseconds) around the peptides investigated. MDPI 2022-04-12 /pmc/articles/PMC9031890/ /pubmed/35455063 http://dx.doi.org/10.3390/life12040572 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Lupi, Laura Bracco, Brenda Sassi, Paola Corezzi, Silvia Morresi, Assunta Fioretto, Daniele Comez, Lucia Paolantoni, Marco Hydration Dynamics of Model Peptides with Different Hydrophobic Character |
title | Hydration Dynamics of Model Peptides with Different Hydrophobic Character |
title_full | Hydration Dynamics of Model Peptides with Different Hydrophobic Character |
title_fullStr | Hydration Dynamics of Model Peptides with Different Hydrophobic Character |
title_full_unstemmed | Hydration Dynamics of Model Peptides with Different Hydrophobic Character |
title_short | Hydration Dynamics of Model Peptides with Different Hydrophobic Character |
title_sort | hydration dynamics of model peptides with different hydrophobic character |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9031890/ https://www.ncbi.nlm.nih.gov/pubmed/35455063 http://dx.doi.org/10.3390/life12040572 |
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