Download MendeleyStructure of human phosphatidylcholine transfer protein in complex with its ligand.
Roderick, S.L., Chan, W.W., Agate, D.S., Olsen, L.R., Vetting, M.W., Rajashankar, K.R., Cohen, D.E.(2002) Nat Struct Biol 9: 507-511
- PubMed: 12055623
- DOI: https://doi.org/10.1038/nsb812
- Primary Citation of Related Structures:
1LN1, 1LN2, 1LN3 - PubMed Abstract:
Phosphatidylcholines (PtdChos) comprise the most common phospholipid class in eukaryotic cells. In mammalian cells, these insoluble molecules are transferred between membranes by a highly specific phosphatidylcholine transfer protein (PC-TP) belonging to the steroidogenic acute regulatory protein related transfer (START) domain superfamily of hydrophobic ligand-binding proteins. The crystal structures of human PC-TP in complex with dilinoleoyl-PtdCho or palmitoyl-linoleoyl-PtdCho reveal that a single well-ordered PtdCho molecule occupies a centrally located tunnel. The positively charged choline headgroup of the lipid engages in cation-pi interactions within a cage formed by the faces of three aromatic residues. These binding determinants and those for the phosphoryl group may be exposed to the lipid headgroup at the membrane-water interface by a conformational change involving the amphipathic C-terminal helix and an Omega-loop. The structures presented here provide a basis for rationalizing the specificity of PC-TP for PtdCho and may identify common features used by START proteins to bind their hydrophobic ligands.
Organizational Affiliation:
Department of Biochemistry, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA. roderick@aecom.yu.edu
