Crystal Structure of the ORP8 Lipid Transport ORD Domain: Model of Lipid Transport

0574877 - ÚOCHB 2024 RIV CH eng J - Journal Article
Eisenreichová, Andrea - Klíma, Martin - Anila, M. M. - Koukalová, Alena - Humpolíčková, Jana - Rozycki, B. - Bouřa, Evžen
Crystal Structure of the ORP8 Lipid Transport ORD Domain: Model of Lipid Transport.
Cells. Roč. 12, č. 15 (2023), č. článku 1974. E-ISSN 2073-4409
R&D Projects: GA ČR(CZ) GF21-27735K
Institutional support: RVO:61388963
Keywords : lipid transport * ORD * ORP8 * PS * PI4P * plasma membrane * ER
OECD category: Biochemistry and molecular biology
Impact factor: 6, year: 2022
Method of publishing: Open access
https://doi.org/10.3390/cells12151974

ORPs are lipid-transport proteins belonging to the oxysterol-binding protein family. They facilitate the transfer of lipids between different intracellular membranes, such as the ER and plasma membrane. We have solved the crystal structure of the ORP8 lipid transport domain (ORD8). The ORD8 exhibited a β-barrel fold composed of anti-parallel β-strands, with three α-helices replacing β-strands on one side. This mixed alpha–beta structure was consistent with previously solved structures of ORP2 and ORP3. A large cavity (≈1860 Å3) within the barrel was identified as the lipid-binding site. Although we were not able to obtain a lipid-bound structure, we used computer simulations based on our crystal structure to dock PS and PI4P molecules into the putative lipid-binding site of the ORD8. Comparative experiments between the short ORD8ΔLid (used for crystallography) and the full-length ORD8 (lid containing) revealed the lid’s importance for stable lipid binding. Fluorescence assays revealed different transport efficiencies for PS and PI4P, with the lid slowing down transport and stabilizing cargo. Coarse-grained simulations highlighted surface-exposed regions and hydrophobic interactions facilitating lipid bilayer insertion. These findings enhance our comprehension of ORD8, its structure, and lipid transport mechanisms, as well as provide a structural basis for the design of potential inhibitors.
Permanent Link: https://hdl.handle.net/11104/0344801


Research data: PDB