Dendrimer-Linked Antifreeze Proteins Have Superior Activity and Thermal Recovery.
By binding to ice, antifreeze proteins (AFPs) depress the freezing point of a solution and inhibit ice recrystallization if freezing does occur. Previous work showed that the activity of an AFP was incrementally increased by fusing it to another protein. Even larger increases in activity were achieved by doubling the number of ice-binding sites by dimerization. Here, we have combined the two strategies by linking multiple outward-facing AFPs to a dendrimer to significantly increase both the size of the molecule and the number of ice-binding sites. Using a heterobifunctional cross-linker, we attached between 6 and 11 type III AFPs to a second-generation polyamidoamine (G2-PAMAM) dendrimer with 16 reactive termini. This heterogeneous sample of dendrimer-linked type III constructs showed a greater than 4-fold increase in freezing point depression over that of monomeric type III AFP. This multimerized AFP was particularly effective at ice recrystallization inhibition activity, likely because it can simultaneously bind multiple ice surfaces. Additionally, attachment to the dendrimer has afforded the AFP superior recovery from heat denaturation. Linking AFPs together via polymers can generate novel reagents for controlling ice growth and recrystallization.
Department of Biomedical and Molecular Sciences, Queen's University , Kingston, Ontario K7L 3N6, Canada.
Corey A
CA
Stevens
Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot 7610001, Israel.
Ran
R
Drori
Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot 7610001, Israel.
Shiran
S
Zalis
Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot 7610001, Israel.
Ido
I
Braslavsky
Department of Biomedical and Molecular Sciences, Queen's University , Kingston, Ontario K7L 3N6, Canada.
Peter L
PL
Davies
D021301:Antifreeze Proteins / Q000737:chemistry*; D003460:Crystallization; D050091:Dendrimers / Q000737:chemistry*; D005615:Freezing; D007053:Ice; D008958:Models, Molecular; D008970:Molecular Weight; D011487:Protein Conformation
D021301:Antifreeze Proteins; D050091:Dendrimers; D007053:Ice; C104700:PAMAM Starburst