Bloom F R, Levin M S, Foor F, Tyler B
J Bacteriol. 1978 May;134(2):569-77. doi: 10.1128/jb.134.2.569-577.1978.
A lambda phage (lambdaNK55) carrying the translocatable element Tn10, conferring tetracycline resistance (Tetr), has been utilized to isolate glutamine auxotrophs of Escherichia coli K-12. Such strains lack uridylyltransferase as a result of an insertion of the TN10 element in the glnD gene. The glnD::Tn10 insertion has been mapped at min 4 on the E. coli chromosome and 98% contransducible by phage P1 with dapD. A lambda transducing phage carrying the glnD gene has been identified. A glnD::Tn10 strain synthesizes highly adenylylated glutamine synthetase under all conditions of growth and fails to accumulate high levels of glutamine synthetase in response to nitrogen limitation. However, this strain, under nitrogen-limiting conditions, allows synthesis of 10 to 20 milliunits of biosynthetically active glutamine synthetase per mg of protein, which is sufficient to allow slow growth in the absence of glutamine. The GlnD phenotype in E. coli can be suppressed by the presence of mutations which increase the quantity of biosynthetically active glutamine synthetase.
携带可转移元件Tn10（赋予四环素抗性，Tetr）的λ噬菌体（λNK55）已被用于分离大肠杆菌K-12的谷氨酰胺营养缺陷型菌株。由于TN10元件插入glnD基因，这些菌株缺乏尿苷酰转移酶。glnD::Tn10插入已定位在大肠杆菌染色体的4分钟处，并且与dapD基因可被噬菌体P1共转导98%。已鉴定出携带glnD基因的λ转导噬菌体。glnD::Tn10菌株在所有生长条件下都合成高度腺苷酸化的谷氨酰胺合成酶，并且在氮限制条件下不能积累高水平的谷氨酰胺合成酶。然而，该菌株在氮限制条件下，每毫克蛋白质可合成10至20毫单位的生物合成活性谷氨酰胺合成酶，这足以使其在没有谷氨酰胺的情况下缓慢生长。大肠杆菌中的GlnD表型可被增加生物合成活性谷氨酰胺合成酶数量的突变所抑制。
