4gh0
Crystal structure of D48V mutant of human GLTP bound with 12:0 monosulfatide
Structural highlights
FunctionGLTP_HUMAN Accelerates the intermembrane transfer of various glycolipids. Catalyzes the transfer of various glycosphingolipids between membranes but does not catalyze the transfer of phospholipids. May be involved in the intracellular translocation of glucosylceramides.[1] [2] [3] [4] Publication Abstract from PubMedHuman glycolipid transfer protein (hsGLTP) forms the prototypical GLTP fold and is characterized by a broad transfer selectivity for glycosphingolipids (GSLs). The GLTP mutation D48V near the `portal entrance' of the glycolipid binding site has recently been shown to enhance selectivity for sulfatides (SFs) containing a long acyl chain. Here, nine novel crystal structures of hsGLTP and the SF-selective mutant complexed with short-acyl-chain monoSF and diSF in different crystal forms are reported in order to elucidate the potential functional roles of lipid-mediated homodimerization. In all crystal forms, the hsGLTP-SF complexes displayed homodimeric structures supported by similarly organized intermolecular interactions. The dimerization interface always involved the lipid sphingosine chain, the protein C-terminus (C-end) and alpha-helices 6 and 2, but the D48V mutant displayed a `locked' dimer conformation compared with the hinge-like flexibility of wild-type dimers. Differences in contact angles, areas and residues at the dimer interfaces in the `flexible' and `locked' dimers revealed a potentially important role of the dimeric structure in the C-end conformation of hsGLTP and in the precise positioning of the key residue of the glycolipid recognition centre, His140. DeltaY207 and DeltaC-end deletion mutants, in which the C-end is shifted or truncated, showed an almost complete loss of transfer activity. The new structural insights suggest that ligand-dependent reversible dimerization plays a role in the function of human GLTP. Structural insights into lipid-dependent reversible dimerization of human GLTP.,Samygina VR, Ochoa-Lizarralde B, Popov AN, Cabo-Bilbao A, Goni-de-Cerio F, Molotkovsky JG, Patel DJ, Brown RE, Malinina L Acta Crystallogr D Biol Crystallogr. 2013 Apr;69(Pt 4):603-16. doi:, 10.1107/S0907444913000024. Epub 2013 Mar 14. PMID:23519669[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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