Disruption of galactokinase signature sequence in gal3p of Saccharomyces cerevisiae does not lead to loss of signal transduction function.
Gal3p of Saccharomyces cerevisiae is a 520-amino-acid residue protein, which activates the GAL genes in the presence of galactose by relieving the repression of Gal80p. It shows significant amino acid sequence homology to galactokinases but does not possess galactokinase activity. Deletion mutants of Gal3p were generated to identify the role of N-terminal amino acid residues required for function. The mutant versions of Gal3p could be detected on a Western blot. The Gal3p mutant lacking N-terminal 50-amino-acid residues which is disrupted for galactokinase signature sequence was found to be functional. These results suggest that the evolutionarily conserved galactokinase signature sequence present in known galactokinases may not have a role in Gal3p function.
Murthy
T V
TV
Molecular Genetics Laboratory, Indian Institute of Technology, Powai, Mumbai, 400 076, India.
Jayadeva Bhat
P
P
D000595:Amino Acid Sequence; D001483:Base Sequence; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D005686:Galactokinase / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
D005656:Fungal Proteins; C099289:Gal3 protein, S cerevisiae; D009838:Oligodeoxyribonucleotides; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D005686:Galactokinase