Use of bacterial two-hybrid system to investigate the molecular interaction between the regulators NifA and NifL of Enterobacter cloacae.
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.
Liao
Gongxian
G
Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, China.
Yu
Guanqiao
G
Shen
Shanjiong
S
Zhu
Jiabi
J