Tomato EF-Ts(mt), a functional mitochondrial translation elongation factor from higher plants.
Ethylene-induced ripening in tomato (Lycopersicon esculentum) resulted in the accumulation of a transcript designated LeEF-Ts(mt) that encodes a protein with significant homology to bacterial Ts translational elongation factor (EF-Ts). Transient expression in tobacco and sunflower protoplasts of full-length and truncated LeEF-Ts(mt)-GFP fusion constructs and confocal microscopy observations clearly demonstrated the targeting of LeEF-Ts(mt) to mitochondria and not to chloroplasts and the requirement for a signal peptide for the proper sorting of the protein. Escherichia coli recombinant LeEF-Ts(mt) co-eluted from Ni-NTA resins with a protein corresponding to the molecular weight of the elongation factor EF-Tu of E. coli, indicating an interaction with bacterial EF-Tu. Increasing the GDP concentration in the extraction buffer reduced the amount of EF-Tu in the purified LeEF-Ts(mt) fraction. The purified LeEF-Ts(mt) stimulated the poly(U)-directed polymerization of phenylalanine 10-fold in the presence of EF-Tu. Furthermore, LeEF-Ts(mt) was capable of catalysing the nucleotide exchange reaction with E. coli EF-Tu. Altogether, these data demonstrate that LeEF-Ts(mt) encodes a functional mitochondrial EF-Ts. LeEF-Ts(mt) represents the first mitochondrial elongation factor to be isolated and functionally characterized in higher plants.
Benichou
Mohamed
M
UMR 990 INP/ENSAT-INRA, Avenue de l'Agrobiopole, BP 107, 31326 Castanet-Tolosan Cedex, France.
Li
Zhengguo
Z
Tournier
Barthélémy
B
Chaves
Ana
A
Zegzouti
Hicham
H
Jauneau
Alain
A
Delalande
Corinne
C
Latché
Alain
A
Bouzayen
Mondher
M
Spremulli
Linda L
LL
Pech
Jean-Claude
JC
D000595:Amino Acid Sequence; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics*; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010445:Peptide Elongation Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010944:Plants / Q000235:genetics*; D011072:Poly U / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D020662:Guanine Nucleotide Exchange Factors; D008164:Luminescent Proteins; D010445:Peptide Elongation Factors; D011993:Recombinant Fusion Proteins; C023512:elongation factor Ts; D049452:Green Fluorescent Proteins; D011072:Poly U