Regulation of Herbaspirillum seropedicae NifA by the GlnK PII signal transduction protein is mediated by effectors binding to allosteric sites

New views on PII signaling: from nitrogen sensing to global metabolic control

“…It had been assumed for quite a while that the Mg 2+ -ATP + 2-OGcomplexed state and post-translational modification of PII prevents any interaction of PII with other targets. Recently, however, PII targets have been identified which select these states [41][42][43]. This highlights the sensing and structural flexibility in PII signaling (see e.g., [21,[26][27][28])…”

Molecular Mechanism and Agricultural Application of the NifA–NifL System for Nitrogen Fixation

“…The N–terminal PAS domain can bind and hydrolyze ATP, but only the C–terminal domain can form the stabilized complex with NifA [ 63 ]. Besides γ–proteobacteria, NifL homologs have also been characterized in α–, β–, and ζ–proteobacteria, but few studies have described the regulation of NifL in these proteobacteria [ 64 , 65 ].…”

The importance of Rhizobium, Agrobacterium, Bradyrhizobium, Herbaspirillum, Sinorhizobium in sustainable agricultural production

“…Ammonium ions through a mechanism involving its N-terminal domain control the activity of NifA, and Nterminal domain inhibits NifA-dependent transcriptional activation by an inter-domain cross-talk between the catalytic domain of the NifA protein and its regulatory N-terminal domain in response to fixed nitrogen (Monteiro et al, 2001). The activity of NifA is negatively influenced by oxygen (Monteiro et al, 1999;Souza et al, 1999;Oliveira et al, 2009), but interaction with Glnk positively influence it, and binding of 2-OG and MgATP to Glnk are very important for NifA activation (Stefanello et al, 2020). Its oxygen sensitivity may attribute to a conserved motif of cysteine residues in NifA which spans the central AAA+ domain and the interdomain linker which connects the AAA+ domain to the C-terminal DNA binding domain (Oliveira et al, 2009).…”