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Vol 46(2012) N 4 p. 514-521; Y.Q. Hua1, Y. Li2, W. Qing2, Z.H. Rong2, S. Qiang3 Cloning and Expression of a Novel Antifreeze Protein AFP72 from the Beetle Tenebrio molitor 1Department of Life Science and Technology, Xinxiang Medical College, Xinxiang, 453003, China2Department of Experimental Center, Henan Institute of Science and Technology, Xinxiang, 453003, China 3College of Life Sciences, Henan Normal University, Xinxiang, Xinxiang, 453007, China *lixiamczj@sina.com Received - 2011-06-15; Accepted - 2011-07-19 A novel antifreeze protein AFP72 cDNA (GenBank accession No. AY929389) was obtained by RT-PCR from Tenebrio molitor. The 216 bp fragment encodes a protein of 72 amino acid residues. Sequence analysis revealed that the cDNA displays a high degree of homology with T. molitor antifreeze proteins, ranging up to 90.78%. Recombinant plasmids pMAL-p2X-afp72 and pMAL-c2X-afp72 were transferred into E. coli TBI to induce a MBP fusion protein by IPTG. The target fusion protein was released from the periplasm and cytoplasm by the cold osmotic shock procedure and sonication respectively. The content of the fusion protein came up to 38.9 and 41.5% of the total dissolved protein, respectively. The fusion protein was purified through an amylose affinity column, and incised by factor Xa. Molecular sieve chromatography was used to achieve a high state of purity of the target protein. The purified target protein di splayed a single band in SDS-PAGE. The fusion protein was shown to increase resistance to low temperatures in bacteria. This finding could help in further investigations of the properties and function of antifreeze proteins. Tenebrio molitor, antifreeze protein, fusion expression, affinity purification, biological activity |