Journal article
A novel nucleotide incorporation activity implicated in the editing of mitochondrial transfer RNAs in Acanthamoeba castellanii
RNA (Cambridge), Vol.5(2), pp.302-317
02/1999
DOI: 10.1017/S1355838299981840
PMCID: PMC1369761
PMID: 10024181
Abstract
In Acanthamoeba castellanii, most of the
mtDNA-encoded tRNAs are edited by a process that replaces
one or more of the first three nucleotides at their 5′
ends. As a result, base pairing potential is restored at
acceptor stem positions (1:72, 2:71, and/or 3:70, in standard
tRNA nomenclature) that are mismatched according to the
corresponding tRNA gene sequence. Here we describe a novel
nucleotide incorporation activity, partially purified from
A. castellanii mitochondria, that has properties
implicating it in mitochondrial tRNA editing in this organism.
This activity is able to replace nucleotides at the first
three positions of a tRNA (positions 1, 2, and 3), matching
the newly incorporated residues through canonical base
pairing to the respective partner nucleotide in the 3′
half of the acceptor stem. Labeling experiments with natural
(Escherichia coli tRNATyr) and synthetic
(run-off transcripts corresponding to A. castellanii
mitochondrial tRNALeu1) substrates suggest that
the nucleotide incorporation activity consists of at least
two components, a 5′ exonuclease or endonuclease
and a template-directed 3′-to-5′ nucleotidyltransferase.
The nucleotidyltransferase component displays an ATP requirement
and generates 5′ pppN... termini in vitro. The development
of an accurate and efficient in vitro system opens the
way for detailed studies of the biochemical properties
of this novel activity and its relationship to mitochondrial
tRNA editing in A. castellanii. In addition, the
system will allow delineation of the structural features
in a tRNA that identify it as a substrate for the labeling
activity.
Details
- Title: Subtitle
- A novel nucleotide incorporation activity implicated in the editing of mitochondrial transfer RNAs in Acanthamoeba castellanii
- Creators
- DAVID H PRICE - Department of Biochemistry, Dalhousie University, Halifax, Nova Scotia B3H 4H7, CanadaMICHAEL W GRAY - Department of Biochemistry, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
- Resource Type
- Journal article
- Publication Details
- RNA (Cambridge), Vol.5(2), pp.302-317
- DOI
- 10.1017/S1355838299981840
- PMID
- 10024181
- PMCID
- PMC1369761
- NLM abbreviation
- RNA
- ISSN
- 1355-8382
- eISSN
- 1469-9001
- Publisher
- Cambridge University Press
- Number of pages
- 16
- Language
- English
- Date published
- 02/1999
- Academic Unit
- Biochemistry and Molecular Biology
- Record Identifier
- 9984024537102771
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