Evidence for an RNA-based catalytic mechanism in eukaryotic nuclear ribonuclease P.

View/ Open
Issue Date
2000Author
Thoms, Brian C.
Chamberlain, Joel
Engelke, David R.
Gegenheimer, Peter Albert
Publisher
RNA Society
Type
Article
Article Version
Scholarly/refereed, publisher version
Metadata
Show full item recordAbstract
Ribonuclease P is the enzyme responsible for removing the 5'-leader segment of precursor transfer RNAs in all organisms. All eukaryotic nuclear RNase Ps are ribonucleoproteins in which multiple protein components and a single RNA species are required for activity in vitro as well as in vivo. It is not known, however, which subunits participate directly in phosphodiester-bond hydrolysis. The RNA subunit of nuclear RNase P is evolutionarily related to its catalytically active bacterial counterpart, prompting speculation that in eukaryotes the RNA may be the catalytic component. In the bacterial RNase P reaction, Mg(II) is required to coordinate the nonbridging phosphodiester oxygen(s) of the scissile bond. As a consequence, bacterial RNase P cannot cleave pre-tRNA in which the pro-Rp nonbridging oxygen of the scissile bond is replaced by sulfur. In contrast, the RNase P reaction in plant chloroplasts is catalyzed by a protein enzyme whose mechanism does not involve Mg(II) coordinated by the pro-Rp oxygen. To determine whether the mechanism of nuclear RNase P resembles more closely an RNA- or a protein-catalyzed reaction, we analyzed the ability of Saccharomyces cerevisiae nuclear RNase P to cleave pre-tRNA containing a sulfur substitution of the pro-Rp oxygen at the cleavage site. Sulfur substitution at this position prohibits correct cleavage of pre-tRNA. Cleavage by eukaryotic RNase P thus depends on the presence of a thio-sensitive ligand to the pro-Rp oxygen of the scissile bond, and is consistent with a common, RNA-based mechanism for the bacterial and eukaryal enzymes.
Description
This is the published version. Copyright 2000 by the RNA Society.
Collections
Citation
Thomas, Brian C., Joel Chamberlain, David R. Engelke, and Peter Gegenheimer. "Evidence for an RNA-based Catalytic Mechanism in Eukaryotic Nuclear Ribonuclease P." Rna 6.4 (2000): 554-62. Web.
Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.
We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.