Dissecting the ABA signalling pathway with a biological chemistry approach

点击翻译按钮获取中文摘要

Abscisic acid (ABA) is a key plant hormone that controls a wide range of processes from plant development to biotic and abiotic stress responses as plants synthesize ABA to initiate various defense mechanisms. One family of key players in this process are the ABA receptors that are members of the so-called pyrabactin resistance (PYR) and PYR-like (PYL) proteins. This diverse family of PYR/PYL proteins consists of at least 14 members in Arabidopsis that all function in ABA binding and consequent signalling. While previous structural studies of the PYL1 protein have revealed a well-conserved ABA binding pocket and a binding site for members of the 2C protein phosphatases (PP2C) responsible for signal transduction, the diverse roles of the PYL1 proteins in development are poorly understood.Aim: We have identified a series of chemical compounds with distinct biological effects on plant growth and development that are thought to be PYL1 ligands. These compounds can be used as chemical probes to further elucidate the roles of different family members in stress response and signal transduction. Furthermore, the compounds possess the potential to control germination and development, an area of great interest to our industrial partner, Tozer Seeds, Lt. The aim of this project is to investigate the molecular basis of ligand binding using a combination of biophysical and structural methods to design and synthesize chemical compounds with improved biological activities.Methods: Protein targets will be expressed in E. coli - based well-established methods using synthetic gene constructs. Biophysical methods range from high-throughput thermal shift assays (TSA) to highly accurate isothermal titration calorimetry (ITC). Co-crystallisation experiment will begin with the known condition for PYL1 and will then be extended to other family members. Structural and biophysical data will be used to guide the synthesis of new compounds. This project represents a collaboration with Tozer Seeds Ltd, UK's largest independent vegetable seed company,where biological tests will be performed during a 3-month placement.