Cloning and characterisation of nifLA regulatory mutations from Klebsiella pneumoniae

✍ Scribed by Filser, Mechthild ;Merrick, Mike ;Cannon, Frank

• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 985 KB
• Volume: 191
• Category: Article
• ISSN: 0026-8925
• DOI: 10.1007/bf00425767

✦ Synopsis

A total of nine regulatory mutations in the nifLA operon of Klebsiella pneumoniae were cloned in the high copy-number plasmid vector pACYCI84. The regulatory phenotypes of the resultant clones were then correlated with their restriction maps and their ability to synthesise nifL and nifA polypeptides in vivo. One mutation, nifL2401, was identified as a 400 bp. deletion within the nifL gene. This mutation was non-polar and caused a Nif ÷ phenotype which showed escape from repression by oxygen and low levels of fixed nitrogen. Identification of this deletion allows the first definitive allocation of a mutation with this phenotype to the n/fL gene and provides further evidence for the role of the n/fL gene product in n/f-specific repression.