GENETIC AND BIOCHEMICAL-CHARACTERIZATION OF THE 2 GLUTAMINE SYNTHETASES GSI AND GSII OF THE PHOSPHINOTHRICYL-ALANYL-ALANINE PRODUCER, STREPTOMYCES-VIRIDOCHROMOGENES TU494
GENETIC AND BIOCHEMICAL-CHARACTERIZATION OF THE 2 GLUTAMINE SYNTHETASES GSI AND GSII OF THE PHOSPHINOTHRICYL-ALANYL-ALANINE PRODUCER, STREPTOMYCES-VIRIDOCHROMOGENES TU494
复制标题
DOI：
10.1099/00221287-139-8-1773
复制
发表时间：
1993-08-01
期刊：
影响因子：
--
通讯作者：
WOHLLEBEN, W
中科院分区：
文献类型：
--
作者：
HILLEMANN, D;DAMMANN, T;WOHLLEBEN, W
利用PCR扩增出病毒色链霉菌谷氨酰胺合成酶I （GSI）编码区1410 bp，并对其进行了克隆和测序。所得GSI蛋白（469个残基）分子量为50 kDa。该DNA区域与coelicolor链霉菌A3(2) glnA基因核苷酸序列一致性达90%，但与S. viridochromogenes的glnII（GSII）基因核苷酸序列相似性不显著。病毒色素s染色体glnA和glnII基因被位点特异性诱变破坏。glnA和glnII单突变体的生长都不需要谷氨酰胺，它们的产孢量都是正常的。对不同氮源培养的GS活性测定表明，热稳定型（CSI）和热不稳定型（GSII）总是同时表达，以GSI活性为主。可以认为，在氮过量的条件下，GSI而不是GSII通过腺苷化而失活。氨基酸和核苷酸可抑制CSI和GSII的活性。
The 1410 bp DNA region (glnA) encoding glutamine synthetase I (GSI) from Streptomyces viridochromogenes was amplified by PCR, cloned and sequenced. The molecular mass of the deduced GSI protein (469 residues) was determined to be 50 kDa. The DNA region showed 90 % nucleotide identity with the Streptomyces coelicolor A3(2) glnA gene, but no significant nucleotide sequence similarity with the glnII(GSII) gene of S. viridochromogenes. The chromosomal glnA and glnII genes of S. viridochromogenes were disrupted by site-specific mutagenesis. Neither glnA nor glnII single mutants required glutamine for growth and both were normal in their sporulation. Measurement of the GS activity in cultures grown with different nitrogen sources revealed that CSI (heat-stable) and GSII (heat-labile) were always expressed together, with GSI as the predominant activity. It could be proposed that GSI, but not GSII is inactivated by adenylylation under conditions of nitrogen excess. CSI and GSII activities are inhibited by amino acids and by nucleotides.