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Many ectotherms organisms produce antifreeze proteins (AFPs) which inhibit the growth of ice by binding to the surface of ice crystals. In this study, a novel antifreeze protein gene from the desert beetle Anatolica polita (named as Apafp752) was expressed in a high level in Escherichia coli strain BL21 (DE3). An approximately 30 kDa fusion protein thioredoxin (Trx)-ApAFP752 was purified through Ni-NTA affinity chromatography and gel filtration chromatography. The activity of the purified fusion protein Trx-ApAFP752 was analyzed by thermal hysteresis activity (THA) and cryoprotection assay. The results suggested that Trx-ApAFP752 conferred freeze resistance on bacterium in a concentration- and time-dependent manner and the cryoprotective effect increased under alkaline conditions. Circular Dichroism (CD) spectrum analysis showed that the recombinant protein of ApAFP752 possessing beta-sheet as the main structure was stable under a wide range of pH from 2.0 to 11.0 and thermal stability below 50 degrees C. The predicted 3D structure showed that Trx-ApAFP752 could form a beta-helix structure on the antifreeze protein part, which placed most of the Thr in a regular array on one side of the protein to form a putative ice-binding surface. (C) 2011 Elsevier Inc. All rights reserved.