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dc.contributor.authorThomas, Brian C.
dc.contributor.authorLi, Xinqiang
dc.contributor.authorGegenheimer, Peter Albert
dc.date.accessioned2015-04-14T20:56:46Z
dc.date.available2015-04-14T20:56:46Z
dc.date.issued2000
dc.identifier.citationThomas, Brian C., Xinqiang Li, and Peter Gegenheimer. "Chloroplast Ribonuclease P Does Not Utilize the Ribozyme-type Pre-tRNA Cleavage Mechanism." Rna 6.4 (2000): 545-53. http://rnajournal.cshlp.org/content/6/4/545.en_US
dc.identifier.urihttp://hdl.handle.net/1808/17418
dc.descriptionThis is the published version. Copyright 2000 by the RNA Society.en_US
dc.description.abstractThe transfer RNA 5' maturation enzyme RNase P has been characterized in Bacteria, Archaea, and Eukarya. The purified enzyme from all three kingdoms is a ribonucleoprotein containing an essential RNA subunit; indeed, the RNA subunit of bacterial RNase P RNA is the sole catalytic component. In contrast, the RNase P activity isolated from spinach chloroplasts lacks an RNA component and appears to function as a catalytic protein. Nonetheless, the chloroplast enzyme recognizes a pre-tRNA substrate for E. coli RNase P and cleaves it as efficiently and precisely as does the bacterial enzyme. To ascertain whether there are differences in catalytic mechanism between an all-RNA and an all-protein RNase P, we took advantage of the fact that phosphodiester bond selection and hydrolysis by the E. coli RNase P ribozyme is directed by a Mg2+ ion coordinated to the nonbridging pro-Rp oxygen of the scissile bond, and is blocked by sulfur replacement of this oxygen. We therefore tested the ability of the chloroplast enzyme to process a precursor tRNA containing this sulfur substitution. Partially purified RNase P from spinach chloroplasts can accurately and efficiently process phosphorothioate-substituted pre-tRNAs; cleavage occurs exclusively at the thio-containing scissile bond. The enzymatic throughput is fivefold slower, consistent with a general chemical effect of the phosphorothioate substitution rather than with a metal coordination deficiency. The chloroplast RNase P reaction mechanism therefore does not involve a catalytic Mg2+ bonded to the pro-Rp phosphate oxygen, and hence is distinct from the mechanism of the bacterial ribozyme RNase P.en_US
dc.publisherRNA Societyen_US
dc.titleChloroplast ribonuclease P does not utilize the ribozyme-type pre-tRNA cleavage mechanism.en_US
dc.typeArticle
kusw.kuauthorThomas, Brian C.
kusw.kuauthorLi, Xinqiang
kusw.kuauthorGegenheimer, Peter Albert
kusw.kudepartmentMolecular Biosciencesen_US
dc.identifier.orcidhttps://orcid.org/0000-0001-9091-0830
kusw.oaversionScholarly/refereed, publisher version
kusw.oapolicyThis item does not meet KU Open Access policy criteria.
dc.rights.accessrightsopenAccess


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