Controlling the Heterodimerisation of the Phytosulfokine Receptor 1 (PSKR1) via Island Loop Modulation

• Published in: International journal of molecular sciences Vol. 22; no. 4; p. 1806
• Main Authors: de Souza, João V, Kondal, Matthew, Zaborniak, Piotr, Cairns, Ryland, Bronowska, Agnieszka K
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 11.02.2021; MDPI AG
• Subjects: Arabidopsis - chemistry; Arabidopsis - metabolism; Arabidopsis Proteins - agonists; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - metabolism; crop control; island loop; Ligands; metadynamics; molecular dynamics; Molecular Dynamics Simulation; phytosulfokine receptor 1; Plant Growth Regulators - chemistry; Plant Growth Regulators - metabolism; Plant Hormone; Protein Domains; Protein Structure, Secondary; Receptors, Cell Surface - agonists; Receptors, Cell Surface - chemistry; Receptors, Cell Surface - metabolism; metadynamics; Plant Hormone; phytosulfokine receptor 1; island loop; molecular dynamics; crop control
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms22041806

Phytosulfokine (PSK) is a phytohormone responsible for cell-to-cell communication in plants, playing a pivotal role in plant development and growth. The binding of PSK to its cognate receptor, PSKR1, is modulated by the formation of a binding site located between a leucine-rich repeat (LRR) domain of PSKR1 and the loop located in the receptor's island domain (ID). The atomic resolution structure of the extracellular PSKR1 bound to PSK has been reported, however, the intrinsic dynamics of PSK binding and the architecture of the PSKR1 binding site remain to be understood. In this work, we used atomistic molecular dynamics (MD) simulations and free energy calculations to elucidate how the PSKR1 island domain (ID) loop forms and binds PSK. Moreover, we report a novel "druggable" binding site which could be exploited for the targeted modulation of the PSKR1-PSK binding by small molecules. We expect that our results will open new ways to modulate the PSK signalling cascade via small molecules, which can result in new crop control and agricultural applications.