Unifying Polar and Hydrophobic Models of Ice Recognition by Antifreeze Glycoproteins

Abstract Antifreeze glycoproteins (AFGPs) enable polar organisms to survive at subzero temperatures by inhibiting ice growth through selective association with specific crystallographic planes. However, the molecular basis of this interaction and its remarkable selectivity remain incompletely understood, and both polar and hydrophobic binding models have been proposed. Here, we combine the synthesis of AFGP variants with high-resolution NMR spectroscopy, antifreeze activity measurements, and molecular dynamics simulations to investigate the molecular determinants of ice recognition. Minimally perturbative chemical modifications, including site-specific deuteration and fluorination, were used to probe the contributions of nonpolar and polar interactions while preserving the characteristic AFGP conformation. The combined structure–activity relationships and computational analyses support an integrative binding model that provides a unified and parsimonious interpretation of the experimental observations. Within this framework, our experimental evidence is consistent with the view that dispersive interactions involving peptide and carbohydrate methyl groups favor productive association with the ice surface, whereas carbohydrate hydroxyl groups, together with sugar- and backbone-associated water molecules, contribute polar interactions that promote selective and persistent binding. This model reconciles key aspects of previously proposed polar and hydrophobic descriptions and provides a molecular rationale for the characteristic plane selectivity of AFGPs and the conservation of specific sequence motifs. More broadly, our results highlight minimally perturbative isotopic substitution and fluorinated molecular editing as useful chemical strategies for probing weak dispersive contributions to complex molecular recognition processes while preserving native molecular architecture.

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Publication Details

Journal
Journal of the American Chemical Society
Published
2026-11-11
DOI
https://doi.org/10.1021/jacs.6c14020
Primary Topic
Protein Structure and Dynamics
Type
article
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article

Unifying Polar and Hydrophobic Models of Ice Recognition by Antifreeze Glycoproteins

Alejandro Villacampa, Jesús Manuel Peregrina, Qinghua Liao, Sakae Tsuda et al.
Journal of the American Chemical Society
Protein Structure and Dynamics
article

Unifying Polar and Hydrophobic Models of Ice Recognition by Antifreeze Glycoproteins

Alejandro Villacampa, Jesús Manuel Peregrina, Qinghua Liao, Sakae Tsuda, Alicia Asín, Benjamin G. Davis, Laura Díaz‐Casado, Andrés G. Santana, Mattia Ghirardello, Fayna García Martín, Juan Luis Asensio, Hiroshi Hinou, Jesús Jiménez‐Barbero, Akari Yamauchi, Jesús H. Busto, Ester Jiménez‐Moreno, Shin‐Ichiro Nishimura, Ramón Hurtado‐Guerrero, Francisco Corzana, Carme Rovira, Alba Nin‐Hill, Pierre Çarçabal, Alberto Avenoza, Ana María Gómez, Tatsuya J. Arai, Emilio J. Cocinero, Claudia Sánchez-García, Julio Zabalza, Ismael Compañón
article en

Abstract

Abstract Antifreeze glycoproteins (AFGPs) enable polar organisms to survive at subzero temperatures by inhibiting ice growth through selective association with specific crystallographic planes. However, the molecular basis of this interaction and its remarkable selectivity remain incompletely understood, and both polar and hydrophobic binding models have been proposed. Here, we combine the synthesis of AFGP variants with high-resolution NMR spectroscopy, antifreeze activity measurements, and molecular dynamics simulations to investigate the molecular determinants of ice recognition. Minimally perturbative chemical modifications, including site-specific deuteration and fluorination, were used to probe the contributions of nonpolar and polar interactions while preserving the characteristic AFGP conformation. The combined structure–activity relationships and computational analyses support an integrative binding model that provides a unified and parsimonious interpretation of the experimental observations. Within this framework, our experimental evidence is consistent with the view that dispersive interactions involving peptide and carbohydrate methyl groups favor productive association with the ice surface, whereas carbohydrate hydroxyl groups, together with sugar- and backbone-associated water molecules, contribute polar interactions that promote selective and persistent binding. This model reconciles key aspects of previously proposed polar and hydrophobic descriptions and provides a molecular rationale for the characteristic plane selectivity of AFGPs and the conservation of specific sequence motifs. More broadly, our results highlight minimally perturbative isotopic substitution and fluorinated molecular editing as useful chemical strategies for probing weak dispersive contributions to complex molecular recognition processes while preserving native molecular architecture.

Journal of the American Chemical Society
Université Paris-Sud (FR), Ikerbasque (ES), Institució Catalana de Recerca i Estudis Avançats (ES), University of Copenhagen (DK), Centre National de la Recherche Scientifique (FR), Consejo Superior de Investigaciones Científicas (ES), Universidad de La Rioja (ES), University of the Basque Country (ES), Hokkaido University (JP), Universidad de Zaragoza (ES), University of Oxford (GB), Fundacion Agencia Aragonesa para la Investigacion y el Desarrollo (ES), Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (ES), Rosalind Franklin Institute (GB), Instituto de Productos Naturales y Agrobiología (ES), Instituto Biofisika (ES), Instituto de Química Orgánica General (ES), Universitat de Barcelona (ES)
Protein Structure and Dynamics
DOIOpen Access PDFOpenAlex
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