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. 1998 Aug 15;26(16):3634–3639. doi: 10.1093/nar/26.16.3634

Trypanosoma brucei U insertion and U deletion activities co-purify with an enzymatic editing complex but are differentially optimized.

J Cruz-Reyes 1, L N Rusché 1, B Sollner-Webb 1
PMCID: PMC147759  PMID: 9685476

Abstract

RNA editing, the processing that generates functional mRNAs in trypanosome mitochondria, involves cycles of protein catalyzed reactions that specifically insert or delete U residues. We recently reported purification from Trypanosoma brucei mitochondria of a complex showing seven major polypeptides which exhibits the enzymatic activities inferred in editing and that a pool of fractions of the complex catalyzed U deletion, the minor form of RNA editing in vivo . We now show that U insertion activity, the major form of RNA editing in vivo , chromatographically co-purifies with both U deletion activity and the protein complex. Furthermore, these editing activities co-sediment at approximately 20 S. U insertion does not require a larger, less characterized complex, as has been suggested and could have implied that the editing machinery would not function in a processive manner. We also show that U insertion is optimized at rather different and more exacting reaction conditions than U deletion. By markedly reducing ATP and carrier RNA and increasing UTP and carrier protein relative to standard editing conditions, U insertion activity of the purified fraction is enhanced approximately 100-fold.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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