1SX6

Crystal structure of human Glycolipid Transfer protein in lactosylceramide-bound form

Summary for 1SX6

• Entry DOI: 10.2210/pdb1sx6/pdb
• Related: 1SWX
• Related PRD ID: PRD_900004
• Descriptor: Glycolipid transfer protein, beta-D-galactopyranose-(1-4)-beta-D-glucopyranose, SPHINGOSINE, ... (6 entities in total)
• Functional Keywords: glycosphingolipid transfer protein-lactosylceramide complex, lipid transport
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 1
• Total formula weight: 24916.26

Authors

Malinina, L.,Malakhova, M.L.,Teplov, A.,Brown, R.E.,Patel, D.J. (deposition date: 2004-03-30, release date: 2004-08-31, Last modification date: 2023-08-23)

Primary citation

Malinina, L.,Malakhova, M.L.,Teplov, A.,Brown, R.E.,Patel, D.J.
Structural basis for glycosphingolipid transfer specificity.
Nature, 430:1048-1053, 2004

PubMed Abstract: Lipid transfer proteins are important in membrane vesicle biogenesis and trafficking, signal transduction and immunological presentation processes. The conserved and ubiquitous mammalian glycolipid transfer proteins (GLTPs) serve as potential regulators of cell processes mediated by glycosphingolipids, ranging from differentiation and proliferation to invasive adhesion, neurodegeneration and apoptosis. Here we report crystal structures of apo-GLTP (1.65 A resolution) and lactosylceramide-bound (1.95 A) GLTP, in which the bound glycosphingolipid is sandwiched, after adaptive recognition, within a previously unknown two-layer all-alpha-helical topology. Glycosphingolipid binding specificity is achieved through recognition and anchoring of the sugar-amide headgroup to the GLTP recognition centre by hydrogen bond networks and hydrophobic contacts, and encapsulation of both lipid chains, in a precisely oriented manner within a 'moulded-to-fit' hydrophobic tunnel. A cleft-like conformational gating mechanism, involving two interhelical loops and one alpha-helix of GLTP, could enable the glycolipid chains to enter and leave the tunnel in the membrane-associated state. Mutation and functional analyses of residues in the glycolipid recognition centre and within the hydrophobic tunnel support a framework for understanding how GLTPs acquire and release glycosphingolipids during lipid intermembrane transfer and presentation processes.

PubMed: 15329726
DOI: 10.1038/nature02856

Experimental method

X-RAY DIFFRACTION (1.95 Å)