1o6u
From Proteopedia
The Crystal Structure of Human Supernatant Protein Factor
Structural highlights
FunctionS14L2_HUMAN Carrier protein. Binds to some hydrophobic molecules and promotes their transfer between the different cellular sites. Binds with high affinity to alpha-tocopherol. Also binds with a weaker affinity to other tocopherols and to tocotrienols. May have a transcriptional activatory activity via its association with alpha-tocopherol. Probably recognizes and binds some squalene structure, suggesting that it may regulate cholesterol biosynthesis by increasing the transfer of squalene to a metabolic active pool in the cell. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSupernatant protein factor (SPF) promotes the epoxidation of squalene catalyzed by microsomes. Several studies suggest its in vivo role in the cholesterol biosynthetic pathway by a yet unknown mechanism. SPF belongs to a family of lipid binding proteins called CRAL_TRIO, which include yeast phosphatidylinositol transfer protein Sec14 and tocopherol transfer protein TTP. The crystal structure of human SPF at a resolution of 1.9 A reveals a two domain topology. The N-terminal 275 residues form a Sec14-like domain, while the C-terminal 115 residues consist of an eight-stranded jelly-roll barrel similar to that found in many viral protein structures. The ligand binding cavity has a peculiar horseshoe-like shape. Contrary to the Sec14 crystal structure, the lipid-exchange loop is in a closed conformation, suggesting a mechanism for lipid exchange. Crystal structure of the human supernatant protein factor.,Stocker A, Tomizaki T, Schulze-Briese C, Baumann U Structure. 2002 Nov;10(11):1533-40. PMID:12429094[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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