Characterization of RNase P from Thermotoga maritima

The protein subunit of RNase P from a thermophilic bacterium, Thermotoga maritima, was overexpressed in and purified from Escherichia coli, The cloned protein was reconstituted with the RNA subunit transcribed::in vitro, The temperature optimum of the holoenzyme is near 50 degreesC, with no enzymatic activity at 65 degreesC or above, This finding is in sharp contrast to the optimal growth temperature of T.maritima, which is near 80 degreesC, However, in heterologous reconstitution experiments in vitro with RNase P subunits from other species, we found that the protein subunit from T.maritima was responsible for the comparative thermal stability of such complexes.