TY - JOUR

T1 - The increased ice-binding affinity of antifreeze protein is attributable to the presence of its oligomeric forms

AU - Baranova, Svetlana V.

AU - Zhdanova, Polina V.

AU - Коваль, Владимир Васильевич

PY - 2025

Y1 - 2025

N2 - One of the key strategies that organisms use to survive in harsh environments is the production of antifreeze proteins, which can bind to ice (IBPs). By binding to ice crystals and thereby inhibiting their growth, IBPs assist organisms in resisting the effects of freezing. Despite the scientific community's significant interest in IBPs, the molecular basis of how these proteins recognize and bind ice remains to be fully elucidated. The present study hypothesizes that the activity of these natural proteins is equivalent to the area of the ice binding site. The object of study is a small protein of 12.5 kDA from Rhagium mordax (RmAFP). Its crystal structure is characterised by a β-solenoid fold, which is accompanied by a broad, flat ice-binding surface. A notable structural characteristic of RmAFP is that the β-layer of the ice interaction surface contains a single motif comprising Thr residues, thereby hindering the formation of the ice-like water structure necessary for binding. The data demonstrate that the oligomerisation of RmAFP enhances the abundance of the Thr-rich motif, thereby facilitating the structuring of water into ice. We demonstrated by mass spectrometry the presence of oligomeric forms of RmAFP in solution. Through modelling, we proposed a series of potential structures for RmAFP oligomers, which possess a comparatively flat surface area deemed essential for ice binding. We also proposed a model for the binding of oligomeric forms of this protein to the ice surface. Our obtained results indicate that a molecule containing several RmAFP domains in an oligomeric complex acquires an increased affinity for ice binding. The modeling of structures suggests the existence of such forms RmAFP in solution, characterized by a sufficiently flat surface containing the amino acids necessary for binding to ice crystals. This work was supported by the Russian state-funded project for ICBFM SB RAS (No FWGN-2025-0020).

AB - One of the key strategies that organisms use to survive in harsh environments is the production of antifreeze proteins, which can bind to ice (IBPs). By binding to ice crystals and thereby inhibiting their growth, IBPs assist organisms in resisting the effects of freezing. Despite the scientific community's significant interest in IBPs, the molecular basis of how these proteins recognize and bind ice remains to be fully elucidated. The present study hypothesizes that the activity of these natural proteins is equivalent to the area of the ice binding site. The object of study is a small protein of 12.5 kDA from Rhagium mordax (RmAFP). Its crystal structure is characterised by a β-solenoid fold, which is accompanied by a broad, flat ice-binding surface. A notable structural characteristic of RmAFP is that the β-layer of the ice interaction surface contains a single motif comprising Thr residues, thereby hindering the formation of the ice-like water structure necessary for binding. The data demonstrate that the oligomerisation of RmAFP enhances the abundance of the Thr-rich motif, thereby facilitating the structuring of water into ice. We demonstrated by mass spectrometry the presence of oligomeric forms of RmAFP in solution. Through modelling, we proposed a series of potential structures for RmAFP oligomers, which possess a comparatively flat surface area deemed essential for ice binding. We also proposed a model for the binding of oligomeric forms of this protein to the ice surface. Our obtained results indicate that a molecule containing several RmAFP domains in an oligomeric complex acquires an increased affinity for ice binding. The modeling of structures suggests the existence of such forms RmAFP in solution, characterized by a sufficiently flat surface containing the amino acids necessary for binding to ice crystals. This work was supported by the Russian state-funded project for ICBFM SB RAS (No FWGN-2025-0020).

UR - https://febs.onlinelibrary.wiley.com/doi/10.1002/2211-5463.70071

M3 - Conference article

VL - 15

SP - 76

JO - FEBS Open Bio

JF - FEBS Open Bio

SN - 2211-5463

IS - S2

M1 - P-02-013

ER -