Crystallization and X-ray crystallographic analysis of the PH-like domain of lipid transfer protein anchored at membrane contact sites from Saccharomyces cerevisiae

Lam6 is a member of sterol-specific lipid transfer proteins anchored at membrane contact sites (LAMs). Lam6 localizes to the ER-mitochondria contact sites by its PH-like domain and the C-terminal transmembrane helix. Here, we purified and crystallized the Lam6 PH-like domain from Saccharomyces cerevisiae. To aid crystallization of the Lam6 PH-like domain, T4 lysozyme was fused to the N-terminus of the Lam6 PH-like domain with a short dipeptide linker, GlySer. The fusion protein was crystallized under the condition of 0.1 M HEPES-HCl pH 7.0, 10% (w/v) PEG 8000, and 0.1 M Na3Citrate at 293K. X-ray diffraction data of the crystals were collected to 2.4 Å resolution using synchrotron radiation. The crystals belong to the orthorhombic space group P212121 with unit cell parameters a = 59.5 Å, b = 60.1 Å, and c = 105.6 Å. The asymmetric unit contains one T4L-Lam6 molecule with a solvent content of 58.7%. The initial attempt to solve the structure by molecular replacement using the T4 lysozyme structure was successful.