Abstract
Ionotropic glutamate receptors (iGluRs) are ligand-gated ion channels that play crucial roles in the central nervous system. iGluR homologs, termed glutamate receptor-like channels (GLRs), have been found in plants. Investigating the structural and functional relationship between iGluRs and GLRs was limited by GLR protein expression, purification, and structural characterization. Here, we provide a detailed protocol for Arabidopsis thaliana GLR3.4 (AtGLR3.4) expression in a mammalian cell line and purification for structure determination by cryogenic electron microscopy (cryo-EM). For the complete details on the use and execution of this protocol, please refer to Green et al. (2021).