肺炎克雷伯菌固氮酶启动子的突变分析：nifA和ntrC（glnG）产物进行正调控所必需的序列。

Mutational analysis of the Klebsiella pneumoniae nitrogenase promoter: sequences essential for positive control by nifA and ntrC (glnG) products.

作者信息

Ow D W, Xiong Y, Gu Q, Shen S C

出版信息

J Bacteriol. 1985 Mar;161(3):868-74. doi: 10.1128/jb.161.3.868-874.1985.

DOI:10.1128/jb.161.3.868-874.1985

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC214977/

Abstract

ntr (nitrogen regulated) and nif (nitrogen fixation) promoters are structurally similar to each other but bear no resemblance to canonic Escherichia coli promoters. ntr promoters are normally activated by the ntrC (glnG) product, but they can also be activated by the ntrC-related Klebsiella pneumoniae nifA product. In contrast, nif promoters of K. pneumoniae such as the nitrogenase (nifH) promoter can only be nifA activated. In this paper, we report the isolation and characterization of 28 mutants of the K. pneumoniae nifH promoter. Class A mutants no longer respond to nifA-mediated transcription, and class B mutants can now respond to ntrC-mediated activation. These two classes of mutants define sequences important to nifA- and ntrC-mediated transcription. Most surprising is that a single base change is sufficient to convert a nifA-activated promoter into an ntrC-activated one.

摘要

ntr（氮调节）和nif（固氮）启动子在结构上彼此相似，但与典型的大肠杆菌启动子没有相似之处。ntr启动子通常由ntrC（glnG）产物激活，但它们也可以被与ntrC相关的肺炎克雷伯菌nifA产物激活。相比之下，肺炎克雷伯菌的nif启动子，如固氮酶（nifH）启动子，只能被nifA激活。在本文中，我们报告了肺炎克雷伯菌nifH启动子的28个突变体的分离和表征。A类突变体不再对nifA介导的转录作出反应，而B类突变体现在可以对ntrC介导的激活作出反应。这两类突变体定义了对nifA和ntrC介导的转录很重要的序列。最令人惊讶的是，单个碱基变化就足以将一个nifA激活的启动子转变为一个ntrC激活的启动子。