Characterization of RNase P from Thermotoga maritima

The protein subunit of RNase P from a thermophilic bacterium, Thermotoga ma ritima, was overexpressed in and purified from Escherichia coil, The cloned protein was reconstituted with the RNA subunit transcribed::in vitro, The temperature optimum of the holoenzyme is near 50 degreesC, with no enzymati c activity at 65 degreesC or above, This finding is in sharp contrast to th e optimal growth temperature of T.maritima, which is near 80 degreesC, Howe ver, in heterologous reconstitution experiments in vitro with RNase P subun its from other species, we found that the protein subunit from T.maritima w as responsible for the comparative thermal stability of such complexes.