Elmerich C, Houmard J, Sibold L, Manheimer I, Charpin N
Mol Gen Genet. 1978 Oct 4;165(2):181-9. doi: 10.1007/BF00269905.
Polar mutations were obtained by integration of bacteriophage Mu c+ or Mu cts DNA into the Klebsiella pneumoniae nif genes located on plasmid pCE1, a derivative of pRD1. In addition, nif deletions were isolated from nif::Mu cts plasmids. Complementation data allowed the characterization of twelve nif cistrons, nine corresponding to previously identified genes. Polar effect of Mu DNA insertions suggested the existence of at least six transcription units: 1) nif K, nif D and nif H--2)nif A and nif L--3) nif E and a new gene--4) nif B--5) nif F--6) nif J. Nif K, nif D and nif H, which are most probably the structural genes for nitrogenase, seem to belong to the same operon transcribed from nif H to nif K. This was confirmed by SDS gel autoradiography of pulse labelled proteins. Moreover it was possible to identify, on the autoradiograms, a polypeptide which likely is the product of nif J and whose biosynthesis is under the control of nif A.
通过将噬菌体Mu c+或Mu cts DNA整合到位于质粒pCE1（pRD1的衍生物）上的肺炎克雷伯菌固氮基因中，获得了极性突变。此外，从nif::Mu cts质粒中分离出了固氮基因缺失突变体。互补数据使得对12个固氮顺反子进行了表征，其中9个与先前鉴定的基因相对应。Mu DNA插入的极性效应表明至少存在6个转录单元：1）nif K、nif D和nif H；2）nif A和nif L；3）nif E和一个新基因；4）nif B；5）nif F；6）nif J。nif K、nif D和nif H很可能是固氮酶的结构基因，它们似乎属于从nif H转录到nif K的同一个操纵子。脉冲标记蛋白的SDS凝胶放射自显影证实了这一点。此外，在放射自显影片上有可能鉴定出一种多肽，它可能是nif J的产物，其生物合成受nif A的控制。
