LAUSR

Deschampsia antarctica has managed to colonize the maritime Antarctic. One of the main factors associated with its tolerance to low temperatures is the presence of apoplastic proteins with antifreeze activity. This work focuses on the effect of cold acclimation of D. antarctica on the accumulation of apoplastic proteins with antifreeze activity. Antifreeze proteins (AFPs) present in apoplastic extracts were purified by ice affinity purification, and their identity was determined by protein sequencing. After 22 days of cold acclimation at 4°C, between 12 and 16 days was achieved to obtain the highest content of apoplastic proteins with antifreeze activity. Sequencing indicated a protein identification probability over the 95%. Percentage coverage was 74% with D. antarctica ice recrystallization inhibition protein 1 (DaIRIP1) and 55% with D. antarctica ice recrystallization inhibition protein 3 (DaIRIP3). The acclimation of D. antarctica has proven to be relevant to improving the yield of apoplastic proteins, and resulting in an increase in the antifreeze activity of these extracts. Our in silico analysis suggests that the fluctuations presented by the 3D structures of DaIRIPs helped to understand the presence of certain IRIPs in apoplastic extracts under the cold acclimation conditions evaluated.