Design and Synthesis of Truncated EGF-A Peptides that Restore LDL-R Recycling in the Presence of PCSK9 In Vitro

• Structure-based design was used to identify inhibitors of the PCSK9/LDL-R complex
• Small EGF-A-based inhibitors of PCSK9 were identified based on rational design
• The peptides retained binding affinity as well as functional activity for PCSK9
• The structure of an EGF-A-based inhibitor was determined in complex with PCSK9

SummaryDisrupting the binding interaction between proprotein convertase (PCSK9) and the epidermal growth factor-like domain A (EGF-A domain) in the low-density lipoprotein receptor (LDL-R) is a promising strategy to promote LDL-R recycling and thereby lower circulating cholesterol levels. In this study, truncated 26 amino acid EGF-A analogs were designed and synthesized, and their structures were analyzed in solution and in complex with PCSK9. The most potent peptide had an increased binding affinity for PCSK9 (KD = 0.6 μM) compared with wild-type EGF-A (KD = 1.2 μM), and the ability to increase LDL-R recycling in the presence of PCSK9 in a cell-based assay.