Molecular characterization of GCV3, the Saccharomyces cerevisiae gene coding for the glycine cleavage system hydrogen carrier protein.
YAL044, a gene on the left arm of Saccharomyces cerevisiae chromosome one, is shown to code for the H-protein subunit of the multienzyme glycine cleavage system. The gene designation has therefore been changed to GCV3, reflecting its role in the glycine cleavage system. GCV3 encodes a 177-residue protein with a putative mitochondrial targeting signal at its amino terminus. Targeted gene replacement shows that GCV3 is not required for growth on minimal medium; however, it is essential when glycine serves as the sole nitrogen source. Studies of GCV3 expression revealed that it is highly regulated. Supplementation of minimal medium with glycine, the glycine cleavage system's substrate, induced expression at least 30-fold. In contrast, and consistent with the cleavage of glycine providing activated single-carbon units, the addition of the metabolic end products that require activated single-carbon units repressed expression about 10-fold. Finally, like many amino acid biosynthetic genes, GCV3 is subject to regulation by the general amino acid control system.
Nagarajan
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Department of Chemistry and Biochemistry and the Department of Biology, Concordia University, Montreal, Quebec H3G 1M8, Canada.
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D000594:Amino Acid Oxidoreductases; D000595:Amino Acid Sequence; D000619:Aminohydrolases / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics*; D005574:Formate-Tetrahydrofolate Ligase / Q000378:metabolism; D005561:Formates / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005998:Glycine / Q000096:biosynthesis; D050961:Glycine Decarboxylase Complex H-Protein; D050841:Glycine Dehydrogenase (Decarboxylating); D008754:Methylenetetrahydrofolate Dehydrogenase (NADP) / Q000378:metabolism; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; D005561:Formates; C483978:GCV3 protein, S cerevisiae; D050961:Glycine Decarboxylase Complex H-Protein; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; C030544:formic acid; C021836:formyl-methenyl-methylenetetrahydrofolate synthetase; D000594:Amino Acid Oxidoreductases; C494237:GCV2 protein, S cerevisiae; D050841:Glycine Dehydrogenase (Decarboxylating); D008754:Methylenetetrahydrofolate Dehydrogenase (NADP); D000619:Aminohydrolases; D005574:Formate-Tetrahydrofolate Ligase; D009584:Nitrogen; D005998:Glycine