RNA '98 (the RNA Society), Madison, WI

Characterization of an archaeal RNase P holoenzyme.

TOM HALL*, and JAMES W. BROWN
Department of Microbiology North Carolina State University, Raleigh

RNase P is a ribozyme necessary for removing the 5' leader sequence in the maturation of precursor transfer RNAs in all known organisms. The enzyme typically consists of both RNA and protein components. The RNA component from all Bacteria studied is functional alone in vitro, although the protein subunit gene is necessary to support life in vivo. The RNA components of RNase P from Archaea are severely deficient in catalytic activity in vitro, although they are structurally related to their bacterial counterparts. No archaeal RNase P holoenzyme has been fully characterized. In preliminary studies, catalytic activity of M. thermoautotrophicum delta H RNA was reconstituted in vitro with the protein subunit of the RNase P from the gram-positive bacterium Bacillus subtilis, suggesting structural similarity in the RNA/protein contact regions of the archaeal and bacterial holoenzymes. However, no open reading frame within the fully sequenced genome of Methanobacterium thermoautotrophicum delta H (or any other archaeon) shows obvious sequence similarity to any known bacterial RNase P protein. The goal of the present study is to isolate and characterize the protein component(s) of RNase P from the archaeon Methanobacterium thermoautrophicum delta H.