›› 2008, Vol. 51 ›› Issue (7): 694-699.

• RESEARCH PAPERS • Previous Articles     Next Articles

Comparison of activities of fusion antifreeze proteins from Microdera punctipennis dzhungarica (Coleoptera: Tenebrionidae)

LI Su-Li   

  • Online:2008-07-20 Published:2008-07-20

Abstract: In order to compare the activity differences between the prokaryotic expressed MBP-MpAFP5 and GST-MpAFP5, the two recombinant prokaryotic expression plasmids pGEX-4T-1-Mpafp5 and pMAL-p2x-Mpafp5 were expressed in Escherichia coli BL21(DE3) to obtain two different fusion antifreeze proteins of Microdera punctipennis dzhungarica. The two fusion proteins were purified by affinity chromatograph. SDS-PAGE analysis indicated that both of the fusion antifreeze proteins were highly expressed in soluble fractions. The thermal hysteresis activities (THA) of GST-MpAFP5 and MBP-MpAFP5 at a concentration of 0.5 mg/mL were measured as 0.51℃ and 1.336℃, respectively. The ice crystal morphology of both proteins displayed pyramid shape. Cryoprotection to bacteria experiments showed that the two fusion proteins could protect bacteria survival at subzero 7℃ temperature. Comparatively, MBP-MpAFP5 had higher protective activities than GST-MpAFP5. These results provide basic data for application of the insect antifreeze proteins in the future.

Key words: Microdera punctipennis dzhungarica, antifreeze protein, prokaryotic expresion, thermal hysteresis activity, ice crystal morphology