GENETIC-ANALYSIS OF GAMMA-AMINOBUTYRATE UTILIZATION PATHWAY IN ESCHERICHIA-COLI K-12
GENETIC-ANALYSIS OF GAMMA-AMINOBUTYRATE UTILIZATION PATHWAY IN ESCHERICHIA-COLI K-12
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DOI：
10.1128/jb.117.2.494-501.1974
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发表时间：
1974-01-01
影响因子：
3.2
通讯作者：
HALPERN, YS
中科院分区：
文献类型：
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作者：
DOVER, S;HALPERN, YS
对照突变导致γ-氨基丁酸-α-酮戊二酸转氨酶(GsST，EC 2.6.1.19)和琥珀酸半醛脱氢酶(SSDH，EC 1.2.1.16)活性增加数倍，导致Escherichia coliK-12突变株获得了利用γ-氨基丁酸酯作为唯一氮源的能力。受影响的基因座gabc大约有48%与ThyA基因共转导，位于Te的最小55位。ColiK-12染色体。利用本工作中分离到的GSST缺失突变体DB742，通过间断交配定位了GABA途径中第一个酶GSST的结构基因。突变的基因座gabt位于大约73个The的最小位置。染色体，与gltC基因相近。关于GABA途径的酶在不同生理条件下对分解代谢抑制的敏感性的遗传证据表明，GABA调节子的两个结构基因并不构成一个操纵子。
The control mutation that results in a concomitant severalfold increase in the activities of γ-aminobutyrate-α-ketoglutarate transaminase (GSST, EC 2.6.1.19) and succinic semialdehyde dehydrogenase (SSDH, EC 1.2.1.16), leading to the acquisition of the ability to utilize γ-aminobutyrate (GABA) as the sole source of nitrogen byEscherichia coliK-12 mutants, was mapped by mating and transduction with P1kc. The locus affected,gabC, is approximately 48% co-transduced with thethyAgene, located at min 55 of theE. coliK-12 chromosome. The structural gene of the first enzyme in the GABA pathway, GSST, was mapped by interrupted mating, using one of the GSST-less mutants, DB742, isolated in this work. The mutated locus,gabT, is situated at about min 73 of theE. colichromosome, close to thegltCgene. Genetic evidence concerning the sensitivity of the enzymes of the GABA pathway to catabolite repression under different physiological conditions suggests that the two structural genes of the GABA regulon do not constitute one operon.