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Alanine : glyoxylate aminotransferase of Saccharomyces cerevisiae –encoding gene AGX1 and metabolic significance
Author(s) -
Schlösser Thomas,
Gätgens Cornelia,
Weber Ulrike,
Stahmann K.Peter
Publication year - 2003
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.1058
Subject(s) - biology , auxotrophy , glyoxylate cycle , serine hydroxymethyltransferase , biochemistry , complementation , glycine , serine , alanine , microbiology and biotechnology , enzyme , open reading frame , saccharomyces cerevisiae , genetics , amino acid , gene , peptide sequence , phenotype , escherichia coli
Abstract Alanine : glyoxylate aminotransferase is one of three different enzymes used for glycine synthesis in Saccharomyces cerevisiae . The open reading frame YFL030w (named AGX1 in the following), encoding this enzyme, was identified by comparing enzyme specific activities in knockout strains. While 100% activity was detectable in the parental strain, 2% was found in a YFL030w:: kanMX4 strain. The ORF found at that locus was suspected to encode alanine : glyoxylate aminotransferase because its predicted amino acid sequence showed 23% identity to the human homologue. Since the YFL030w:: kanMX4 strain showed no glycine auxtrophic phenotype, AGX1 was replaced by KanMX4 in a Δ GLY1 Δ SHM1 Δ SHM2 background. These background mutations, which cause inactivation of threonine aldolase, mitochondrial and cytosolic serine hydroxymethyltransferase, respectively, lead to a conditional glycine auxotrophy. This means that growth is not possible on glucose but on ethanol as the sole carbon source. Additional disruption of AGX1 revealed a complete glycine auxotrophy. Complementation was observed by transformation with a plasmid‐encoded AGX1 . Copyright © 2003 John Wiley & Sons, Ltd.