Abstract
In the present study, we investigated the effects of the 22-mer model peptides of Group 3 late embryogenesis abundant (G3LEA) proteins on desiccation-induced aggregation of α-casein. Three kinds of the 22-mer model peptides were synthesized and tested, made of two repeats of the 11-mer consensus motifs characteristic of G3LEA proteins originating from plants, nematodes, and sleeping chironomide (P. vanderplanki). α-casein was aggregated when dried alone. Such aggregation was significantly suppressed in the presence of any of the 22-mer model peptides with the molar ratio of 25 relative to α-casein or higher. However, the aggregation occurred as soon as the selected 22-mer model peptide was added to the aqueous α-casein, when the molar ratio was 10 or lower. The addition of the model peptide was found to let pH values down to near the isoelectric point of α-casein (ca.4), namely its minimal solubility point. On the basis of these results, we discussed the role of the 22-mer model peptides as anti-aggregation reagents.
