Cargando…

Hydrogen Bonding in a l-Glutamine-Based Polyamidoamino Acid and its pH-Dependent Self-Ordered Coil Conformation

This paper reports on synthesis, acid–base properties, and self-structuring in water of a chiral polyamidoamino acid, M-l-Gln, obtained from the polyaddition of N,N′-methylenebisacrylamide with l-glutamine, with the potential of establishing hydrogen bonds through its prim-amide pendants. The M-l-Gl...

Descripción completa

Detalles Bibliográficos
Autores principales: Lazzari, Federica, Manfredi, Amedea, Alongi, Jenny, Ganazzoli, Fabio, Vasile, Francesca, Raffaini, Giuseppina, Ferruti, Paolo, Ranucci, Elisabetta
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240574/
https://www.ncbi.nlm.nih.gov/pubmed/32290338
http://dx.doi.org/10.3390/polym12040881
_version_ 1783536915036766208
author Lazzari, Federica
Manfredi, Amedea
Alongi, Jenny
Ganazzoli, Fabio
Vasile, Francesca
Raffaini, Giuseppina
Ferruti, Paolo
Ranucci, Elisabetta
author_facet Lazzari, Federica
Manfredi, Amedea
Alongi, Jenny
Ganazzoli, Fabio
Vasile, Francesca
Raffaini, Giuseppina
Ferruti, Paolo
Ranucci, Elisabetta
author_sort Lazzari, Federica
collection PubMed
description This paper reports on synthesis, acid–base properties, and self-structuring in water of a chiral polyamidoamino acid, M-l-Gln, obtained from the polyaddition of N,N′-methylenebisacrylamide with l-glutamine, with the potential of establishing hydrogen bonds through its prim-amide pendants. The M-l-Gln showed pH-responsive circular dichroism spectra, revealing ordered conformations. Structuring was nearly insensitive to ionic strength but sensitive to denaturing agents. The NMR diffusion studies were consistent with a population of unimolecular nanoparticles thus excluding aggregation. The M-l-Gln had the highest molecular weight and hydrodynamic radius among all polyamidoamino acids described. Possibly, transient hydrogen bonds between l-glutamine molecules and M-l-Gln growing chains facilitated the polyaddition reaction. Theoretical modeling showed that M-l-Gln assumed pH-dependent self-ordered coil conformations with main chain transoid arrangements reminiscent of the protein hairpin motif owing to intramolecular dipole moments and hydrogen bonds. The latter were most numerous at the isoelectric point (pH 4.5), where they mainly involved even topologically distant main chain amide N–H and side chain amide C=O brought to proximity by structuring. Hydrogen bonds at pH 4.5 were also suggested by variable temperature NMR. The 2D NOESY experiments at pH 4.5 confirmed the formation of compact structures through the analysis of the main chain/side chain hydrogen contacts, in line with MD simulations.
format Online
Article
Text
id pubmed-7240574
institution National Center for Biotechnology Information
language English
publishDate 2020
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-72405742020-06-11 Hydrogen Bonding in a l-Glutamine-Based Polyamidoamino Acid and its pH-Dependent Self-Ordered Coil Conformation Lazzari, Federica Manfredi, Amedea Alongi, Jenny Ganazzoli, Fabio Vasile, Francesca Raffaini, Giuseppina Ferruti, Paolo Ranucci, Elisabetta Polymers (Basel) Article This paper reports on synthesis, acid–base properties, and self-structuring in water of a chiral polyamidoamino acid, M-l-Gln, obtained from the polyaddition of N,N′-methylenebisacrylamide with l-glutamine, with the potential of establishing hydrogen bonds through its prim-amide pendants. The M-l-Gln showed pH-responsive circular dichroism spectra, revealing ordered conformations. Structuring was nearly insensitive to ionic strength but sensitive to denaturing agents. The NMR diffusion studies were consistent with a population of unimolecular nanoparticles thus excluding aggregation. The M-l-Gln had the highest molecular weight and hydrodynamic radius among all polyamidoamino acids described. Possibly, transient hydrogen bonds between l-glutamine molecules and M-l-Gln growing chains facilitated the polyaddition reaction. Theoretical modeling showed that M-l-Gln assumed pH-dependent self-ordered coil conformations with main chain transoid arrangements reminiscent of the protein hairpin motif owing to intramolecular dipole moments and hydrogen bonds. The latter were most numerous at the isoelectric point (pH 4.5), where they mainly involved even topologically distant main chain amide N–H and side chain amide C=O brought to proximity by structuring. Hydrogen bonds at pH 4.5 were also suggested by variable temperature NMR. The 2D NOESY experiments at pH 4.5 confirmed the formation of compact structures through the analysis of the main chain/side chain hydrogen contacts, in line with MD simulations. MDPI 2020-04-10 /pmc/articles/PMC7240574/ /pubmed/32290338 http://dx.doi.org/10.3390/polym12040881 Text en © 2020 by the authors. 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 (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Lazzari, Federica
Manfredi, Amedea
Alongi, Jenny
Ganazzoli, Fabio
Vasile, Francesca
Raffaini, Giuseppina
Ferruti, Paolo
Ranucci, Elisabetta
Hydrogen Bonding in a l-Glutamine-Based Polyamidoamino Acid and its pH-Dependent Self-Ordered Coil Conformation
title Hydrogen Bonding in a l-Glutamine-Based Polyamidoamino Acid and its pH-Dependent Self-Ordered Coil Conformation
title_full Hydrogen Bonding in a l-Glutamine-Based Polyamidoamino Acid and its pH-Dependent Self-Ordered Coil Conformation
title_fullStr Hydrogen Bonding in a l-Glutamine-Based Polyamidoamino Acid and its pH-Dependent Self-Ordered Coil Conformation
title_full_unstemmed Hydrogen Bonding in a l-Glutamine-Based Polyamidoamino Acid and its pH-Dependent Self-Ordered Coil Conformation
title_short Hydrogen Bonding in a l-Glutamine-Based Polyamidoamino Acid and its pH-Dependent Self-Ordered Coil Conformation
title_sort hydrogen bonding in a l-glutamine-based polyamidoamino acid and its ph-dependent self-ordered coil conformation
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240574/
https://www.ncbi.nlm.nih.gov/pubmed/32290338
http://dx.doi.org/10.3390/polym12040881
work_keys_str_mv AT lazzarifederica hydrogenbondinginalglutaminebasedpolyamidoaminoacidanditsphdependentselforderedcoilconformation
AT manfrediamedea hydrogenbondinginalglutaminebasedpolyamidoaminoacidanditsphdependentselforderedcoilconformation
AT alongijenny hydrogenbondinginalglutaminebasedpolyamidoaminoacidanditsphdependentselforderedcoilconformation
AT ganazzolifabio hydrogenbondinginalglutaminebasedpolyamidoaminoacidanditsphdependentselforderedcoilconformation
AT vasilefrancesca hydrogenbondinginalglutaminebasedpolyamidoaminoacidanditsphdependentselforderedcoilconformation
AT raffainigiuseppina hydrogenbondinginalglutaminebasedpolyamidoaminoacidanditsphdependentselforderedcoilconformation
AT ferrutipaolo hydrogenbondinginalglutaminebasedpolyamidoaminoacidanditsphdependentselforderedcoilconformation
AT ranuccielisabetta hydrogenbondinginalglutaminebasedpolyamidoaminoacidanditsphdependentselforderedcoilconformation