6A5E

Crystal structure of plant peptide RALF23 in complex with FER and LLG2

Summary for 6A5E

• Entry DOI: 10.2210/pdb6a5e/pdb
• Descriptor: Receptor-like protein kinase FERONIA, GPI-anchored protein LLG2, RALF23, ... (5 entities in total)
• Functional Keywords: a plant receptor-ligand complex flr, transferase
• Biological source: Arabidopsis thaliana (Mouse-ear cress); More
• Total number of polymer chains: 6
• Total formula weight: 111623.62

Authors

Xiao, Y.,Chai, J. (deposition date: 2018-06-23, release date: 2019-06-26, Last modification date: 2020-07-29)

Primary citation

Xiao, Y.,Stegmann, M.,Han, Z.,DeFalco, T.A.,Parys, K.,Xu, L.,Belkhadir, Y.,Zipfel, C.,Chai, J.
Mechanisms of RALF peptide perception by a heterotypic receptor complex.
Nature, 572:270-274, 2019

PubMed Abstract: Receptor kinases of the Catharanthus roseus RLK1-like (CrRLK1L) family have emerged as important regulators of plant reproduction, growth and responses to the environment. Endogenous RAPID ALKALINIZATION FACTOR (RALF) peptides have previously been proposed as ligands for several members of the CrRLK1L family. However, the mechanistic basis of this perception is unknown. Here we report that RALF23 induces a complex between the CrRLK1L FERONIA (FER) and LORELEI (LRE)-LIKE GLYCOSYLPHOSPHATIDYLINOSITOL (GPI)-ANCHORED PROTEIN 1 (LLG1) to regulate immune signalling. Structural and biochemical data indicate that LLG1 (which is genetically important for RALF23 responses) and the related LLG2 directly bind RALF23 to nucleate the assembly of RALF23-LLG1-FER and RALF23-LLG2-FER heterocomplexes, respectively. A conserved N-terminal region of RALF23 is sufficient for the biochemical recognition of RALF23 by LLG1, LLG2 or LLG3, and binding assays suggest that other RALF peptides that share this conserved N-terminal region may be perceived by LLG proteins in a similar manner. Structural data also show that RALF23 recognition is governed by the conformationally flexible C-terminal sides of LLG1, LLG2 and LLG3. Our work reveals a mechanism of peptide perception in plants by GPI-anchored proteins that act together with a phylogenetically unrelated receptor kinase. This provides a molecular framework for understanding how diverse RALF peptides may regulate multiple processes, through perception by distinct heterocomplexes of CrRLK1L receptor kinases and GPI-anchored proteins of the LRE and LLG family.

PubMed: 31291642
DOI: 10.1038/s41586-019-1409-7

Experimental method

X-RAY DIFFRACTION (2.766 Å)