PMID: 17435765 , Related PDB id: 2P4E
Authors:
Cunningham D, Danley DE, Geoghegan KF, Griffor MC, Hawkins JL, Subashi TA, Varghese AH, Ammirati MJ, Culp JS, Hoth LR, Mansour MN, McGrath KM, Seddon AP, Shenolikar S, Stutzman-Engwall KJ, Warren LC, Xia D, Qiu X
Title:
Structural and biophysical studies of PCSK9 and its mutants linked to familial hypercholesterolemia.
Journal:
Nat Struct Mol Biol. 2007 May;14(5):413-9. Epub 2007 Apr 15.
Abstract:
Proprotein convertase subtilisin kexin type 9 (PCSK9) lowers the abundance of surface low-density lipoprotein (LDL) receptor through an undefined mechanism. The structure of human PCSK9 shows the subtilisin-like catalytic site blocked by the prodomain in a noncovalent complex and inaccessible to exogenous ligands, and that the C-terminal domain has a novel fold. Biosensor studies show that PCSK9 binds the extracellular domain of LDL receptor with K(d) = 170 nM at the neutral pH of plasma, but with a K(d) as low as 1 nM at the acidic pH of endosomes. The D374Y gain-of-function mutant, associated with hypercholesterolemia and early-onset cardiovascular disease, binds the receptor 25 times more tightly than wild-type PCSK9 at neutral pH and remains exclusively in a high-affinity complex at the acidic pH. PCSK9 may diminish LDL receptors by a mechanism that requires direct binding but not necessarily receptor proteolysis.