Expression of the nitrogen fixation (nif ) genes is tightly regulated by two proteins NifA and NifL in the (-subdivision of the proteobacteria. NifA is a transcriptional activator, which can be inactivated by NifL in ...Expression of the nitrogen fixation (nif ) genes is tightly regulated by two proteins NifA and NifL in the (-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.展开更多
基金This work was supported by the National Basic Research Program of China(Grant No.2001CB108904)the Hi-Tech Research and Development Program of China(Grant No.2001AA214021).
基金This work was supported by a grant in aid of the Shanghai Institutes of Biological Sciences, the Chinese Academy of Sciences "973" Project of the Ministry of Science and Technology, China (Grant No. 2001CB108901)
文摘Expression of the nitrogen fixation (nif ) genes is tightly regulated by two proteins NifA and NifL in the (-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.
