Characterization of the glnK-amtB Operon of Azotobacter vinelandii
Characterization of the glnK-amtB Operon of Azotobacter vinelandii
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DOI：
10.1128/jb.180.12.3260-3264.1998
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发表时间：
1998-06
影响因子：
3.2
通讯作者：
D. Meletzus;P. Rudnick;N. Doetsch;A. Green;C. Kennedy
中科院分区：
文献类型：
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作者：
D. Meletzus;P. Rudnick;N. Doetsch;A. Green;C. Kennedy
摘要为了确定棕色固氮菌中PII蛋白是否影响nif基因表达对铵供应通量的调节，分离并表征了编码PII的基因。其推导的翻译产物与其他生物的PII蛋白高度相似，与大肠杆菌glnK基因产物的相关性最大。在大肠杆菌中发现了一个名为amtB的基因，该基因与glnK共转录。杆菌AmtB蛋白类似于来自少数其他真核生物和一种其他原核生物的功能上表征的铵转运蛋白。分离稳定的glnK突变株的尝试没有成功，这表明glnK和glnA一样，是A. vinelandii。amtB突变体被分离出来，尽管在突变体和野生型菌株中在有限量的铵上的生长是相似的，但是突变体不能运输[14C]甲基铵。
ABSTRACT To determine whether in Azotobacter vinelandii the PII protein influences the regulation of nifgene expression in response to fluxes in the ammonium supply, the gene encoding PII was isolated and characterized. Its deduced translation product was highly similar to PII proteins from other organisms, with the greatest degree of relatedness being exhibited to the Escherichia coli glnK gene product. A gene designated amtB was found downstream of and was cotranscribed with glnK as in E. coli. The AmtB protein is similar to functionally characterized ammonium transport proteins from a few other eukaryotes and one other prokaryote.glnK and amtB comprise an operon. Attempts to isolate a stable glnK mutant strain were unsuccessful, suggesting that glnK, like glnA, is an essential gene in A. vinelandii. amtB mutants were isolated, and although growth on limiting amounts of ammonium was similar in the mutant and wild-type strains, the mutants were unable to transport [14C]methylammonium.