Comparative analysis of ATPase of yeast elongation factor 3 and ATPase associated with Tetrahymena ribosomes.
Elongation factor 3 (EF-3) is a unique and essential requirement of the fungal translational apparatus. The biochemical function of EF-3 has recently been defined. The protein removes deacylated tRNA from the ribosomal exit site (E-site) thus facilitating occupation of the ribosomal A-site by aa-tRNA. A functional homolog of yeast EF-3 has not been identified in non-fungal species. Yeast EF-3 is a ribosome-dependent ATPase that can also accept GTP and ITP as substrates. The function of EF-3 in ribosomal reactions requires ATP hydrolysis. An ATPase activity associated with higher eukaryotic ribosomes has been claimed to be a direct functional homolog of yeast EF-3. Comparative analysis of biochemical, immunological and functional properties of ATPase activity associated with the ribosomes isolated from the ciliated protozoan Tetrahymena pyriformis with that of yeast EF-3 ATPase indicates that these two activities are significantly different. Results reported in this communication strongly suggest that the ribosome associated ATP hydrolytic activity of Tetrahymena pyriformis is not a functional homolog of yeast EF-3.
Kovalchuke
O
O
Department of Biochemistry, Medical College of Wisconsin, Milwaukee 53226, USA.
Ziehler
J
J
Chakraburtty
K
K
D000251:Adenosine Triphosphatases / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D005656:Fungal Proteins; D006160:Guanosine Triphosphate / Q000378:metabolism; D008970:Molecular Weight; D010452:Peptide Biosynthesis; D010445:Peptide Elongation Factors / Q000378:metabolism*; D010455:Peptides; D014176:Protein Biosynthesis; D012269:Ribosomal Proteins / Q000032:analysis / Q000737:chemistry; D012270:Ribosomes / Q000201:enzymology*; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins; D013769:Tetrahymena pyriformis / Q000201:enzymology*
D005656:Fungal Proteins; D010445:Peptide Elongation Factors; D010455:Peptides; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; C111584:YEF3 protein, S cerevisiae; C012001:polyphenylalanine; D006160:Guanosine Triphosphate; D000251:Adenosine Triphosphatases