A hyperactive calcium dependent antifreeze protein in an Antarctic bacterium

• Published in: FEMS Microbiology Letters
• Main Authors: Gilbert, J, Davies, P, Laybourn-Parry, J
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Ltd 2005
• Subjects: Biological Sciences; Microbiology; Microbial ecology; Antarctic; Antarc*
• Online Access: http://www.sciencedirect.com; https://doi.org/10.1016/j.femsle.2005.02.022; http://www.ncbi.nlm.nih.gov/pubmed/15796981; http://ecite.utas.edu.au/49098

In cold climates, some plants and bacteria that cannot avoid freezing use antifreeze proteins (AFPs) to lessen the destructiveeffects of ice recrystallization. These AFPs have weak freezing point depression activity, perhaps to avoid sudden, uncontrolledgrowth of ice. Here, we report on an uncharacteristically powerful bacterial AFP found in an Antarctic strain of the bacterium,Marinomonas primoryensis. It is Ca2+-dependent, shows evidence of cooperativity, and can produce over 2 rC of freezing pointdepression. Unlike most AFPs, it does not produce obvious crystal faceting during thermal hysteresis. This AFP might be capableof imparting freezing avoidance to M. primoryensis in ice-covered Antarctic lakes. A hyperactive bacterial AFP has not previouslybeen reported.