Alanine:glyoxylate aminotransferase of Saccharomyces cerevisiae-encoding gene AGX1 and metabolic significance
Alanine:glyoxylate aminotransferase of Saccharomyces cerevisiae-encoding gene AGX1 and metabolic significance
复制标题
DOI：
10.1002/yea.1058
复制
发表时间：
2004-01-15
期刊：
影响因子：
2.6
通讯作者：
Stahmann, KP
中科院分区：
文献类型：
--
作者：
Schlösser, T;Gätgens, C;Stahmann, KP
丙氨酸：乙醛酸氨基转移酶是酿酒酵母中用于合成甘氨酸的三种不同酶之一。通过比较敲除菌株中酶的特异性活性，鉴定出编码该酶的开放阅读框YFL030w（以下命名为AGX1）。在亲本菌株中检测到100%的活性，而在YFL030w::kanMX4菌株中检测到2%的活性。在该位点发现的ORF被怀疑编码丙氨酸：乙醛酸氨基转移酶，因为其预测的氨基酸序列与人类同源物有23%的同源性。由于YFL030w::kanMX4菌株没有表现出甘氨酸营养不良表型，因此在Delta GLY1 Delta SHM1 Delta SHM2背景下，AGX1被kanMX4取代。这些背景突变分别导致苏氨酸醛缩酶、线粒体和细胞质丝氨酸羟甲基转移酶失活，从而导致条件性甘氨酸营养不良。这意味着它不能靠葡萄糖生长，只能靠乙醇作为唯一的碳源。AGX1的额外破坏显示了完全的甘氨酸营养不良。用编码AGX1的质粒转化观察到互补。版权所有：John Wiley Sons， Ltd。
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 Delta GLY1 Delta SHM1 Delta 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 (C) 2003 John Wiley Sons, Ltd.