1. Academic Validation
  2. Identification of a small peptide that inhibits PCSK9 protein binding to the low density lipoprotein receptor

Identification of a small peptide that inhibits PCSK9 protein binding to the low density lipoprotein receptor

  • J Biol Chem. 2014 Jan 10;289(2):942-55. doi: 10.1074/jbc.M113.514067.
Yingnan Zhang 1 Charles Eigenbrot Lijuan Zhou Steven Shia Wei Li Clifford Quan Jeffrey Tom Paul Moran Paola Di Lello Nicholas J Skelton Monica Kong-Beltran Andrew Peterson Daniel Kirchhofer
Affiliations

Affiliation

  • 1 From the Departments of Early Discovery Biochemistry.
Abstract

PCSK9 (proprotein convertase subtilisin/kexin type 9) is a negative regulator of the hepatic LDL receptor, and clinical studies with PCSK9-inhibiting Antibodies have demonstrated strong LDL-c-lowering effects. Here we screened phage-displayed peptide libraries and identified the 13-amino acid linear peptide Pep2-8 as the smallest PCSK9 Inhibitor with a clearly defined mechanism of inhibition that has been described. Pep2-8 bound to PCSK9 with a KD of 0.7 μm but did not bind to other proprotein convertases. It fully restored LDL receptor surface levels and LDL particle uptake in PCSK9-treated HepG2 cells. The crystal structure of Pep2-8 bound to C-terminally truncated PCSK9 at 1.85 Å resolution showed that the peptide adopted a strand-turn-helix conformation, which is remarkably similar to its solution structure determined by NMR. Consistent with the functional binding site identified by an Ala scan of PCSK9, the structural Pep2-8 contact region of about 400 Å(2) largely overlapped with that contacted by the EGF(A) domain of the LDL receptor, suggesting a competitive inhibition mechanism. Consistent with this, Pep2-8 inhibited LDL receptor and EGF(A) domain binding to PCSK9 with IC50 values of 0.8 and 0.4 μm, respectively. Remarkably, Pep2-8 mimicked secondary structural elements of the EGF(A) domain that interact with PCSK9, notably the β-strand and a discontinuous short α-helix, and it engaged in the same β-sheet hydrogen bonds as EGF(A) does. Although Pep2-8 itself may not be amenable to therapeutic applications, this study demonstrates the feasibility of developing peptidic inhibitors to functionally relevant sites on PCSK9.

Keywords

Crystal Structure; LDL Receptor; PCSK9; Peptides; Phage Display; Protease; Protein-Protein Interactions.

Figures
Products
  • Cat. No.
    Product Name
    Description
    Target
    Research Area
  • HY-P2276
    99.74%, PCSK9 Inhibitor