Poly(l-alanine-co-l-threonine succinate) as a Biomimetic Cryoprotectant

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Biochemistry

Background:

• Natural antifreeze glycoproteins (AFGPs) prevent cold damage in organisms through ice-shaping properties.
• Developing synthetic analogs with controlled structures can lead to novel cryoprotective agents.

Purpose of the Study:

• To synthesize and characterize novel [(l-Ala)-co-(l-Thr succinate)] (PATs) as biomimetic antifreezing glycoprotein analogs.
• To evaluate the ice recrystallization inhibition (IRI), ice nucleation inhibition (INI), dynamic ice shaping (DIS), thermal hysteresis (TH), and protein cryopreservation activities of PATs.

Main Methods:

• Synthesis of PATs with fixed molecular weight (10-12 kDa) and Ala/Thr ratio (2:1), varying Ala content and succinylation.
• Assessed IRI, INI, DIS, and TH activities.
• Evaluated protein (lactate dehydrogenase, LDH) stabilization through freeze-thaw cycles.

Main Results:

• PATs with higher l-Ala content showed enhanced IRI and INI.
• High succinylation correlated with observed dynamic ice shaping (DIS) activity.
• PATs, except for PATs-1, effectively stabilized LDH through 15 freeze-thaw cycles.

Conclusions:

• Biomimetic PATs were successfully synthesized by controlling l-Ala content and succinylation.
• PATs with 65-70% l-Ala and 12-19% succinylation exhibited significant cryo-activities.
• These optimized PATs show promise for protein cryoprotection, particularly for LDH.