Xue Z, Jiang Q, Shen S
Sci Sin. 1980 Feb;23(2):261-7.
Two hisD-unlinked genes NifC5 and NifC7 are mapped in the chromosome of K. pneumoniae. The sequence of NifC5 and NifC7 is suggested as NifC5--gltB--NifC7--argG. The P1 infected E. coli lysate can transduce the mutant C-7 to be Nif+ transductant, yet fails to transduce the hisD-linked nif mutants to be Nif+ ones. This indicates that the gene encoding C-7 is not the structural gene of nitrogen fixation and is present in E. coli. It is actually a gene specifying the glutamate synthetase. SDS electrophoresis shows the marked low content of nitrogen reductase and immunoelectrophoretic test reveals the reduced amount of both nitrogenase and nitrogen reductase in the mutant cells.
两个与hisD不连锁的基因NifC5和NifC7定位于肺炎克雷伯菌的染色体上。NifC5和NifC7的序列为NifC5--gltB--NifC7--argG。P1感染的大肠杆菌裂解物可将突变体C-7转导为固氮阳性转导子，但不能将与hisD连锁的固氮突变体转导为固氮阳性转导子。这表明编码C-7的基因不是固氮结构基因，且存在于大肠杆菌中。它实际上是一个编码谷氨酸合成酶的基因。SDS电泳显示固氮还原酶含量显著降低，免疫电泳试验显示突变细胞中固氮酶和固氮还原酶的量均减少。
