Molecule of the Month: Phytosulfokine Receptor
Phytosulfokine and other small peptides deliver signals about growth and development in plants.
Loopy Leucine Repeats
Exploring the Structure
Phytosulfokine and Receptor
In the FLS2 receptor shown above, flagellin acts like glue to stick the receptor and coreceptor together. The phytosulfokine receptor, on the other hand, does this in two steps. Binding of phytosulfokine causes a flexible loop on the receptor to fold into a stable pocket that holds the hormone. This complex is then the perfect shape to bind to the coreceptor. Three structures show the process: in the free receptor (PDB ID 4z62) the loop is so flexible that it is not seen in the structure; PDB ID 4z63 shows the peptide-receptor complex; and PDB ID 4z64 shows the final activated complex. To explore these structures in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- Proteins build from leucine-rich repeats have interesting functions--try searching for "leucine-rich repeat" at the main RCSB PDB site to see some.
- The structures of these receptors typically only have the portion of the protein that is on the outside of the cell. Use the Protein Explorer to find information on the portions that are not included in the structure.
Related PDB-101 Resources
- Browse Biology of Plants
- Browse Cellular Signaling
- Sauter M. (2015) Phytosulfokine peptide signalling. J. Exper. Botany 66, 5161-5169.
- 4z62, 4z63, 4z64: Wang, J., Li, H., Han, Z., Zhang, H., Wang, T., Lin, G., Chang, J., Yang, W., Chai, J. (2015) Allosteric receptor activation by the plant peptide hormone phytosulfokine. Nature 525: 265-268
- Matsubayashi, Y. (2014) Posttranslationally modified small-peptide signals in plants. Annu. Rev. Plant Biol. 65, 385-413
- 4lsx: Santiago, J., Henzler, C., Hothorn, M. (2013) Molecular mechanism for plant steroid receptor activation by somatic embryogenesis co-receptor kinases. Science 341: 889-892
- 4mn8: Sun, Y., Li, L., Macho, A.P., Han, Z., Hu, Z., Zipfel, C., Zhou, J.M., Chai, J. (2013) Structural basis for flg22-induced activation of the Arabidopsis FLS2-BAK1 immune complex. Science 342: 624-628
August 2020, David Goodselldoi:10.2210/rcsb_pdb/mom_2020_8