Formation of NifA-PII complex represses ammonium-sensitive nitrogen fixation in diazotrophic proteobacteria lacking NifL

Autor: Yan Zeng, Lu Guo, Yongqiang Gao, Lingwei Cui, Mengmei Wang, Lu Huang, Mingyue Jiang, Ying Liu, Yaxin Zhu, Hua Xiang, De-Feng Li, Yanning Zheng
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Cell Reports, Vol 43, Iss 7, Pp 114476- (2024)
Druh dokumentu: article
ISSN: 2211-1247
DOI: 10.1016/j.celrep.2024.114476
Popis: Summary: Biological nitrogen fixation catalyzed by nitrogenase contributes greatly to the global nitrogen cycle. Nitrogenase expression is subject to regulation in response to nitrogen availability. However, the mechanism through which the transcriptional activator NifA regulates nitrogenase expression by interacting with PII nitrogen regulatory proteins remains unclear in diazotrophic proteobacteria lacking NifL. Here, we demonstrate that in Rhodopseudomonas palustris grown with ammonium, NifA bound deuridylylated PII proteins to form an inactive NifA-PII complex, thereby inhibiting the expression of nitrogenase. Upon nitrogen limitation, the dissociation of uridylylated PII proteins from NifA resulted in the full restoration of NifA activity, and, simultaneously, uridylylation of the significantly up-regulated PII protein GlnK2 led to the increased expression of NifA in R. palustris. This insight into how NifA interacts with PII proteins and controls nitrogenase expression sets the stage for creating highly efficient diazotrophs, reducing the need for energy-intensive chemical fertilizers and helping to diminish carbon emissions.
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