RNA 2000 (The RNA Society), Madison, WI

Partial purification of Methanococcus jannaschii RNase P holoenzyme.

Andrew J. Andrews*, and JAMES W. BROWN

Department of Microbiology, North Carolina State University, Box 7615, Raleigh, NC 27695

The RNase P RNA from the archaeon Methanococcus jannaschii lacks key secondary structural features for the recognition of pre-tRNA, and as a result is not catalytically active in vitro .  This is in contrast to the Methanobacterium, whose RNase P RNA is catalytically active in the absence of any protein in the appropriate ionic conditions. How the Methanococcus jannaschii RNase P holoenzyme compensates for the missing RNA structural elements is not known.  We have partially purified the Methanococcus jannaschii RNase P holoenzyme for the structural and functional characterization. This enzyme has a buoyant density in CsSO4 of 1.39 g/ml and an apparently large molecular weight of greater than 400kDa.  The holoenzyme has a Km of 32 nM and tolerates a wide range of ionic conditions.  The efficiency of the holoenzyme to carry out the reaction suggests that the protein component(s) of the Methanococcus jannaschii most likely have taken over rolls in structural stability and substrate recognition once carried out by the RNA.