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TbMP42 is a structure-sensitive ribonuclease that likely follows a metal ion catalysis mechanism.

Niemann, Moritz and Brecht, Michael and Schlüter, Elke and Weitzel, Kerstin and Zacharias, Martin and Göringer, H. Ulrich (2008):
TbMP42 is a structure-sensitive ribonuclease that likely follows a metal ion catalysis mechanism.
36, In: Nucleic acids research, (13), pp. 4465-73, ISSN 1362-4962, [Article]

Abstract

RNA editing in African trypanosomes is characterized by a uridylate-specific insertion and/or deletion reaction that generates functional mitochondrial transcripts. The process is catalyzed by a multi-enzyme complex, the editosome, which consists of approximately 20 proteins. While for some of the polypeptides a contribution to the editing reaction can be deduced from their domain structure, the involvement of other proteins remains elusive. TbMP42, is a component of the editosome that is characterized by two C(2)H(2)-type zinc-finger domains and a putative oligosaccharide/oligonucleotide-binding fold. Recombinant TbMP42 has been shown to possess endo/exoribonuclease activity in vitro; however, the protein lacks canonical nuclease motifs. Using a set of synthetic gRNA/pre-mRNA substrate RNAs, we demonstrate that TbMP42 acts as a topology-dependent ribonuclease that is sensitive to base stacking. We further show that the chelation of Zn(2+) cations is inhibitory to the enzyme activity and that the chemical modification of amino acids known to coordinate Zn(2+) inactivates rTbMP42. Together, the data are suggestive of a Zn(2+)-dependent metal ion catalysis mechanism for the ribonucleolytic activity of rTbMP42.

Item Type: Article
Erschienen: 2008
Creators: Niemann, Moritz and Brecht, Michael and Schlüter, Elke and Weitzel, Kerstin and Zacharias, Martin and Göringer, H. Ulrich
Title: TbMP42 is a structure-sensitive ribonuclease that likely follows a metal ion catalysis mechanism.
Language: English
Abstract:

RNA editing in African trypanosomes is characterized by a uridylate-specific insertion and/or deletion reaction that generates functional mitochondrial transcripts. The process is catalyzed by a multi-enzyme complex, the editosome, which consists of approximately 20 proteins. While for some of the polypeptides a contribution to the editing reaction can be deduced from their domain structure, the involvement of other proteins remains elusive. TbMP42, is a component of the editosome that is characterized by two C(2)H(2)-type zinc-finger domains and a putative oligosaccharide/oligonucleotide-binding fold. Recombinant TbMP42 has been shown to possess endo/exoribonuclease activity in vitro; however, the protein lacks canonical nuclease motifs. Using a set of synthetic gRNA/pre-mRNA substrate RNAs, we demonstrate that TbMP42 acts as a topology-dependent ribonuclease that is sensitive to base stacking. We further show that the chelation of Zn(2+) cations is inhibitory to the enzyme activity and that the chemical modification of amino acids known to coordinate Zn(2+) inactivates rTbMP42. Together, the data are suggestive of a Zn(2+)-dependent metal ion catalysis mechanism for the ribonucleolytic activity of rTbMP42.

Journal or Publication Title: Nucleic acids research
Volume: 36
Number: 13
Divisions: 10 Department of Biology > Postranscriptional Gene Regulation and RNA Therapeutics
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10 Department of Biology
Date Deposited: 03 Nov 2011 12:56
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