The enigmatic mitochondrial ORF ymf39 codes for ATP synthase chain b

verfasst von

Gertraud Burger, B. Franz Lang, Hans Peter Braun, Stefanie Marx

Abstract

ymf39 is a conserved hypothetical protein-coding gene found in mitochondrial genomes of land plants and certain protists. We speculated earlier, based on a weak sequence similarity between Ymf39 from a green alga and the atpF gene product from Bradyrhizobium, that ymf39 might code for subunit b of mitochondrial F₀F₁-ATP synthase. To test this hypothesis, we have sequenced ymf39 from five protists with minimally derived mitochondrial genomes, the jakobids. In addition, we isolated the mitochondrial ATP synthase complex of the jakobid Seculamonas ecuadoriensis and determined the partial protein sequence of the 19-kDa subunit, the size expected for Ymf39. The obtained peptide sequence matches perfectly with a 3′-proximal region of the ymf39 gene of this organism, confirming that Ymf39 is indeed an ATP synthase subunit. Finally, we employed statistical tests to assess the significance of sequence similarity of Ymf39 proteins with each other, their nucleus-encoded functional counterparts, ATP4/ATP5F, from fungi and animals and α-proteobacterial ATP synthase b-subunits. This analysis provides clear evidence that ymf39 is an atpF homolog, while ATP4/ATP5F appears to be a highly diverged form of ymf39 that has migrated to the nucleus. We propose to designate ymf39 from now on atp4.

Organisationseinheit(en)

Institut für Pflanzengenetik

Externe Organisation(en)

Université de Montréal

Typ

Artikel

Journal

Nucleic acids research

Band

31

Seiten

2353-2360

Anzahl der Seiten

8

ISSN

0305-1048

Publikationsdatum

01.05.2003

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Genetik

Elektronische Version(en)

https://doi.org/10.1093/nar/gkg326 (Zugang: Offen)