Sandbox Reserved 703
From Proteopedia
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| 2v3q, resolution 1.89Å () | |||||||||
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| Ligands: | , , | ||||||||
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| Resources: | FirstGlance, OCA, RCSB, PDBsum | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
Contents |
Description
HPBP is a 38kDa apoliprotein, and belongs to the family of ubiquitous eukaryotic proteins named DING, an extracellular protein family including four conserved amino acids at its N-terminal end. It is the only known transporter capable of binding phosphate ions in the human plasma. HPBP is bound to PON1, a Ca-dependent enzyme associated to HDL (High Density Lipoprotein), another lipoprotein which enables lipids like cholesterol and triglycerides to be transported from the blood to the liver. It is the place where it can be removed, reducing the amount of arterial cholesterol. HPBP is always copurified with the enzyme paraoxonase (PON1), that is why it was always ignored before 2006. The copurification is the result of a similar molecular weight, strong hydrophobic interactions, and the fact that PON1 is a glycosylated protein. The separation of the two molecules involves a hydroxyapatite chromatography with phosphate concentration gradient elution. Up to now, HPBP has never been characterized or predicted from nucleic acid databases of human genome. Its X-ray structure is similar to the prokaryotic phosphate solute binding proteins (SBPs) associated with ATP binding cassette transmembrane transporters. Their role is to enable the unidirectional transport of substances trough the membrane, using ATP hydrolysis.
Activity and physiological functions
Structure
Applications
External Resources
Contributors
Demir Fijuljanin, Christine Ponkratz
