Amyloidogenic immunoglobulin light chain kinetic stabilizers comprising a simple urea linker module reveal a novel binding sub-site.
Yan, N.L., Nair, R., Chu, A., Wilson, I.A., Johnson, K.A., Morgan, G.J., Kelly, J.W.(2022) Bioorg Med Chem Lett 60: 128571-128571
- PubMed: 35065233 
- DOI: https://doi.org/10.1016/j.bmcl.2022.128571
- Primary Citation of Related Structures:  
7RTP - PubMed Abstract: 
In immunoglobulin light chain (LC) amyloidosis, the misfolding, or misfolding and misassembly of LC a protein or fragments thereof resulting from aberrant endoproteolysis, causes organ damage to patients. A small molecule "kinetic stabilizer" drug could slow or stop these processes and improve prognosis. We previously identified coumarin-based kinetic stabilizers of LCs that can be divided into four components, including a "linker module" and "distal substructure". Our prior studies focused on characterizing carbamate, hydantoin, and spirocyclic urea linker modules, which bind in a solvent-exposed site at the V L -V L domain interface of the LC dimer. Here, we report structure-activity relationship data on 7-diethylamino coumarin-based kinetic stabilizers. This substructure occupies the previously characterized "anchor cavity" and the "aromatic slit". The potencies of amide and urea linker modules terminating in a variety of distal substructures attached at the 3-position of this coumarin ring were assessed. Surprisingly, crystallographic data on a 7-diethylamino coumarin-based kinetic stabilizer reveals that the urea linker module and distal substructure attached at the 3-position bind a solvent-exposed region of the full-length LC dimer distinct from previously characterized sites. Our results further elaborate the small-molecule binding surface of LCs that could be occupied by potent and selective LC kinetic stabilizers.
Organizational Affiliation: 
Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA.