Use of bacterial two-hybrid system to investigate the molecular interaction between the regulators NifA and NifL of Enterobacter cloacae.

Science in China. Series C, Life sciences / Chinese Academy of Sciences

PubMedID: 18762888

Liao G, Yu G, Shen S, Zhu J. Use of bacterial two-hybrid system to investigate the molecular interaction between the regulators NifA and NifL of Enterobacter cloacae. Sci China, C, Life Sci. 2002;45(6):569-76.
Expression of the nitrogen fixation (nif) genes is tightly regulated by two proteins NifA and NifL in the gamma-subdivision of the proteobacteria. NifA is a transcriptional activator, which can be inactivated by NifL in the presence of oxygen or excess fixed nitrogen. A direct interaction between E. cloacae NifL and NifA was detected using the bacterial two-hybrid system. This interaction was accelerated in the presence of fixed nitrogen, while oxygen had no effect. NifL proteins, with their C-terminus being deleted, completely lost the ability to interact with NifA. The data suggest that the C-terminal domain of NifL acts as a sensor of the nitrogen status of the cell and mediates interaction with NifA.