M. mazei glutamine synthetase and glutamine synthetase-GlnK1 structures reveal enzyme regulation by oligomer modulation.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37968329.
- Also identified by DOI 10.1038/s41467-023-43243-w and PMC identifier 10651883.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Glutamine synthetases (GS) play central roles in cellular nitrogen assimilation. Although GS active-site formation requires the oligomerization of just two GS subunits, all GS form large, multi-oligomeric machines. Here we describe a structural dissection of the archaeal Methanosarcina mazei (Mm) GS and its regulation. We show that Mm GS forms unstable dodecamers. Strikingly, we show this Mm GS oligomerization property is leveraged for a unique mode of regulation whereby labile Mm GS hexamers are stabilized by binding the nitrogen regulatory protein, GlnK1. Our GS-GlnK1 structure shows that GlnK1 functions as molecular glue to affix GS hexamers together, stabilizing formation of GS active-sites. These data, therefore, reveal the structural basis for a unique form of enzyme regulation by oligomer modulation.
Medical subject headings
- Glutamate-Ammonia Ligase
- Nitrogen