Abstract

In eukaryotes, ribonuclease P(RNase P) requires both RNA and protein components for catalytic activity. The eukaryotic RNase P RNA, unlike its bacterial counterparts, does not possess intrinsic catalytic activity in the absence of holoenzyme protein components. We have used a sensitive photoreactive cross-linking assay to explore the substrate-binding environment for different eukaryotic RNase P holoenzymes. Protein components from the Tetrahymena thermophila and human RNase P holoenzymes form specific products in photoreactions containing [4-thio]-uridine-labeled pre-tRNA(Gin). The HeLa RNase P RNA in neither the presence nor the absence of holoenzyme protein components formed cross-link products to the pre-tRNA(Gln) probe. Parallel photo-cross-linking experiments with the Escherichia coli RNase P holoenzyme revealed that only the bacterial RNase P RNA forms specific substrate photoadducts. A protein-rich active site for the eukaryotic RNase P represents one unique feature that distinguishes holoenzyme organization between bacteria and eukaryotes.

Original languageEnglish
Pages (from-to)7193-7196
Number of pages4
JournalJournal of Biological Chemistry
Volume273
Issue number13
DOIs
StatePublished - Mar 27 1998

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