A novel cryoprotective protein (CRP) with high activity from the ice-nucleating bacterium, Pantoea agglomerans IF012686

The ice-nucleating bacterium, Pantoea agglomerans IFO12686, induces the cry oprotective protein (CRP) by cold acclimation at 12 degreesC. The CRP mas p urified to apparent homogeneity by various chromatographies. We found that the purified CRP was a monomer of approximately 29,000 according to gel fil tration chromatography and SDS-PAGE, and was a heat-stable protein. The CRP could protect freeze-labile enzymes, lactate dehydroxgenase (ADH), alcohol dehydrogenase (ADH) and isocitrate dehydrogenase (iCDH), against freezing flawing denaturation. The activity of the CRP ii:as about 3.5 x 10(4) times more effective than bovine serum albumin (BSA) and 2 x 10(6) times than CO R26 from the ice-nucleating bacterium Pseudomonas fluorescens KUIN-1. We co nfirmed that the CRP mas a novel protein, as judged by; the a different mol ecule mass from the already-known cryoprotectants, and has an extremely hig h cryoprotective activity.