Characterization and preliminary X-ray crystallographic analysis of an Ice-binding protein (FfIBP) from phychrophilic bacteria, Flavobacterium frigoris

Abstract

The Ice binding protein (IBP) is a prerequisite material for organism to be allowed to live in a subzero environment. Ice growth in a cold environment is fatal for organism which is not just physically destruction of inner cell organelle but also chemical damage such an osmotic shock. IBP has been characterized property of which ability inhibit the ice growth by binding to specific ice plane. Flavobacterium frigoris isolated from Antarctic area produce an ice-binding protein (FfIBP) to survive and reduce damage from ice growth. The FfIBP has been cloned and over-expressed in Escherichia coli. To diagnose ice-binding mechanism, we measured thermal hysteresis (TH) activity which is numerical value of a gap between freezing and melting point as well as ice re-crystallization inhibition activity. Thermal hysteresis activity of the FfIBP was approximately 2.5℃ at 50uM that is 10 times higher than moderately active LeIBP. Furthermore, the Ice Re-crystallization inhibition activity represent the FfIBP has ability to inhibit ice growing at low concentration 2.5uM limit. Consequently the FfIBP was classified as a hyper-active Ice binding protein. Also, preliminary X-ray crystallography was performed to reveal the ice-binding site of FfIBP at the molecular level.e but also chemical damage such an osmotic shock. IBP has been characterized property of which ability inhibit the ice growth by binding to specific ice plane. Flavobacterium frigoris isolated from Antarctic area produce an ice-binding protein (FfIBP) to survive and reduce damage from ice growth. The FfIBP has been cloned and over-expressed in Escherichia coli. To diagnose ice-binding mechanism, we measured thermal hysteresis (TH) activity which is numerical value of a gap between freezing and melting point as well as ice re-crystallization inhibition activity. Thermal hysteresis activity of the FfIBP was approximately 2.5℃ at 50uM that is 10 times higher than moderately a