Preparation of co-crystals of human PPARa-LBD and ligand for high-resolution X-ray crystallography

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptor-type transcription factors with three subtypes (a, d, and g) that regulate cell differen-tiation and metabolism. Co-crystals of human PPARa-ligand-binding domain (LBD)-PPARa ligand for X-ray crystallography have been difficult to obtain. Re-combinant human PPARa-LBD proteins contain intrinsic fatty acids (iFAs of Es-cherichia coli origin) and may be unstable without ligands during crystallization. To circumvent these limitations, we have successfully applied various crystalliza-tion techniques, including co-crystallization, cross-seeding, soaking, delipida-tion, and coactivator peptide supplementation. For complete details on the use and execution of this protocol, please refer to Kamata et al. (2020).