A cold-active heat-labile t-RNA modification GTPase from a psychrophilic bacterium Pseudomonas syringae (Lz4W)

A cold-active heat-labile t-RNA modification GTPase (TrmE) from psychrophilic bacterium Pseudomonas syringae (Lz4W) has been purified and characterized. The purified TrmE is a 53 kDa protein, has GTPase activity and hydrolyses only the oxy and deoxy forms of GTP but not the other nucleotide triphosphates. The enzyme exhibits optimal activity at 12-18 degrees C and retains 65% of its optimal activity at 4 degrees C, indicating that it is a cold-active enzyme. The enzyme is also heat-labile and loses 60% of its activity at 30 degrees C. This is the first report on the purification and characterization of a TrmE from a psychrophilic bacterium. (C) 2009 Elsevier Masson SAS. All rights reserved.