Genetic control of nitrate assimilation in Klebsiella oxytoca. Final technical report

Stewart, Valley J.

Cornell University

关键词: Klebsiella;    Microorganisms;    Enzymes;    Transcription;    Nitrates;   

DOI  :  10.2172/771369
RP-ID  :  DOE/ER/20027-1
RP-ID  :  FG02-91ER20027
RP-ID  :  771369

美国|英语

来源: UNT Digital Library

【 摘 要 】

Some microorganisms can use nitrate as the sole source of nitrogen for biosynthesis. This project focused on the bacterium Klebsiella oxytoca, an enterobacterium found in soil and water. Mutagenesis and molecular cloning identified the nasFEDCBA operon encoding enzymes for the uptake and reduction of nitrate and nitrite to ammonium, and the adjacent nasR regulatory gene. Analysis of nasF operon expression revealed that transcription is activated by the Ntr (general nitrogen regulation ) system in response to nitrogen limitation. Transcription antitermination control in response to nitrate and nitrite is mediated by the NasR protein. Additional work established that the NasR protein is an RNA-binding protein that interacts with nasF operon leader RNA to control transcription readthrough.