Mapping the Binding Site of BMS-708163 on ?-Secretase with Cleavable Photoprobes.

ABSTRACT: ?-Secretase, a four-subunit transmembrane aspartic proteinase, is a highly valued drug target in Alzheimer's disease and cancer. Despite significant progress in structural studies, the respective molecular mechanisms and binding modes of ?-secretase inhibitors (GSIs) and modulators (GSMs) remain uncertain. Here, we developed biotinylated cleavable-linker photoprobes based on the BMS-708163 GSI to study its interaction with ?-secretase. Comparison of four cleavable linkers indicated that the hydrazine-labile N-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde) linker was cleaved most efficiently to release photolabeled and affinity-captured presenilin-1 (PS1), the catalytic subunit of ?-secretase. Peptide mapping showed that the BMS-708163-based probe photoinserted at L282 of PS1. This insertion site was consistent with the results of molecular dynamics simulations of the ?-secretase complex with inhibitor. Taken together, this work reveals the binding site of a GSI and offers insights into the mechanism of action of this class of inhibitors.

SUBMITTER: Gertsik N 

PROVIDER: S-EPMC5516958 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature