7TFB

P. polymyxa GS(14)-Q-GlnR peptide

This is a non-PDB format compatible entry.

Summary for 7TFB

• Entry DOI: 10.2210/pdb7tfb/pdb
• EMDB information: 25868
• Descriptor: GlnR C-tail peptide, Glutamine synthetase, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: glutamine synthetase repressor tetradecamer, biosynthetic protein, ligase
• Biological source: Paenibacillus polymyxa; More
• Total number of polymer chains: 28
• Total formula weight: 754816.94

Authors

Travis, B.A.,Peck, J.,Schumacher, M.A. (deposition date: 2022-01-06, release date: 2022-06-29, Last modification date: 2024-02-28)

Primary citation

Travis, B.A.,Peck, J.V.,Salinas, R.,Dopkins, B.,Lent, N.,Nguyen, V.D.,Borgnia, M.J.,Brennan, R.G.,Schumacher, M.A.
Molecular dissection of the glutamine synthetase-GlnR nitrogen regulatory circuitry in Gram-positive bacteria.
Nat Commun, 13:3793-3793, 2022

PubMed Abstract: How bacteria sense and respond to nitrogen levels are central questions in microbial physiology. In Gram-positive bacteria, nitrogen homeostasis is controlled by an operon encoding glutamine synthetase (GS), a dodecameric machine that assimilates ammonium into glutamine, and the GlnR repressor. GlnR detects nitrogen excess indirectly by binding glutamine-feedback-inhibited-GS (FBI-GS), which activates its transcription-repression function. The molecular mechanisms behind this regulatory circuitry, however, are unknown. Here we describe biochemical and structural analyses of GS and FBI-GS-GlnR complexes from pathogenic and non-pathogenic Gram-positive bacteria. The structures show FBI-GS binds the GlnR C-terminal domain within its active-site cavity, juxtaposing two GlnR monomers to form a DNA-binding-competent GlnR dimer. The FBI-GS-GlnR interaction stabilizes the inactive GS conformation. Strikingly, this interaction also favors a remarkable dodecamer to tetradecamer transition in some GS, breaking the paradigm that all bacterial GS are dodecamers. These data thus unveil unique structural mechanisms of transcription and enzymatic regulation.

PubMed: 35778410
DOI: 10.1038/s41467-022-31573-0

Experimental method

ELECTRON MICROSCOPY (2.28 Å)