De novo designed ice-binding proteins from twist-constrained helices

Area of Science:

• Materials Science
• Protein Engineering
• Biophysics

Background:

• Controlling solidification at the molecular level is vital in materials science.
• Organisms utilize ice-binding proteins (IBPs) to regulate ice formation, but their structure-activity relationships remain unclear.
• Understanding these relationships is key to developing novel antifreeze materials.

Purpose of the Study:

• To investigate the structure-activity relationships of ice-binding proteins (IBPs) using de novo computational protein design.
• To test the hypothesis that alpha-helical undertwisting in antifreeze proteins facilitates ice binding.
• To computationally design novel IBPs with enhanced ice-recrystallization inhibition properties.

Main Methods:

• Employed de novo computational protein design to engineer alpha-helical protein bundles.
• Designed proteins featured a central ice-binding helix with projecting threonine residues and two supporting helices to control alpha-helix twist.
• Assessed ice-recrystallization inhibition activity of designed proteins.

Main Results:

• Designed proteins demonstrated ice-recrystallization inhibition activity.
• A direct correlation was observed between the degree of designed alpha-helix undertwisting and increased ice-recrystallization inhibition.
• The findings validate the hypothesis regarding the role of helix undertwisting in IBP function.

Conclusions:

• De novo computational protein design is an effective strategy for elucidating IBP structure-activity relationships.
• Alpha-helical undertwisting is a critical structural feature for effective ice binding and recrystallization inhibition.
• This study opens new avenues for designing synthetic ice-binding proteins for various applications.