5IXO: Crystal Structure Of The Arabidopsis Receptor Kinase Haesa Lrr Ectdomain (apo Form)

Plants constantly renew during their life cycle and thus require to shed senescent and damaged organs. Floral abscission is controlled by the leucine-rich repeat receptor kinase (LRR-RK) HAESA and the peptide hormone IDA. It is unknown how expression of IDA in the abscission zone leads to HAESA activation. Here we show that IDA is sensed directly by the HAESA ectodomain. Crystal structures of HAESA in complex with IDA reveal a hormone binding pocket that accommodates an active dodecamer peptide. A central hydroxyproline residue anchors IDA to the receptor. The HAESA co-receptor SERK1, a positive regulator of the floral abscission pathway, allows for high-affinity sensing of the peptide hormone by binding to an Arg-His-Asn motif in IDA. This sequence pattern is conserved among diverse plant peptides, suggesting that plant peptide hormone receptors may share a common ligand binding mode and activation mechanism.
PDB ID: 5IXODownload
MMDB ID: 143627
PDB Deposition Date: 2016/3/23
Updated in MMDB: 2016/10
Experimental Method:
x-ray diffraction
Resolution: 1.74  Å
Source Organism:
Similar Structures:
Biological Unit for 5IXO: monomeric; determined by author and by software (PISA)
Molecular Components in 5IXO
Label Count Molecule
Protein (1 molecule)
Receptor-like Protein Kinase 5(Gene symbol: HAE)
Molecule annotation
Chemicals (12 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB