Legume receptors perceive the rhizobial lipochitin oligosaccharide signal molecules by direct binding

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

  • Angelique Broghammer, Danmark
  • Lene Krusell, Danmark
  • Mickaël Blaise, Danmark
  • Jørgen Sauer, Danmark
  • John T Sullivan
  • ,
  • Nicolai Nareth Maolanon, LUKKET: 2012 Nanobiovidenskab, Danmark
  • Maria Vinther
  • Andrea Maria Lorentzen, Institut for Biokemi og Molekylær Biologi, Danmark
  • Esben B Madsen, Danmark
  • Knud J Jensen, Danmark
  • Peter Roepstorff, Institut for Biokemi og Molekylær Biologi, Danmark
  • Søren Skou Thirup
  • Clive W Ronson
  • ,
  • Mikkel B Thygesen, Danmark
  • Jens Stougaard
Lipochitin oligosaccharides called Nod factors function as primary rhizobial signal molecules triggering legumes to develop new plant organs: root nodules that host the bacteria as nitrogen-fixing bacteroids. Here, we show that the Lotus japonicus Nod factor receptor 5 (NFR5) and Nod factor receptor 1 (NFR1) bind Nod factor directly at high-affinity binding sites. Both receptor proteins were posttranslationally processed when expressed as fusion proteins and extracted from purified membrane fractions of Nicotiana benthamiana or Arabidopsis thaliana. The N-terminal signal peptides were cleaved, and NFR1 protein retained its in vitro kinase activity. Processing of NFR5 protein was characterized by determining the N-glycosylation patterns of the ectodomain. Two different glycan structures with identical composition, Man(3)XylFucGlcNAc(4), were identified by mass spectrometry and located at amino acid positions N68 and N198. Receptor-ligand interaction was measured by using ligands that were labeled or immobilized by application of chemoselective chemistry at the anomeric center. High-affinity ligand binding was demonstrated with both solid-phase and free solution techniques. The K(d) values obtained for Nod factor binding were in the nanomolar range and comparable to the concentration range sufficient for biological activity. Structure-dependent ligand specificity was shown by using chitin oligosaccharides. Taken together, our results suggest that ligand recognition through direct ligand binding is a key step in the receptor-mediated activation mechanism leading to root nodule development in legumes.
OriginalsprogEngelsk
TidsskriftProceedings of the National Academy of Sciences of the United States of America
Vol/bind109
Nummer34
Sider (fra-til)13859-13864
Antal sider6
ISSN0027-8424
DOI
StatusUdgivet - 21 aug. 2012

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