RESUMEN
Molecular characterization of the binding epitope of IL-23R and its cognate cytokine IL-23 is paramount to understand the role in autoimmune diseases and to support the discovery of new inhibitors of this protein-protein interaction. Our results revealed that HDX-MS was able to identify the binding epitope of IL-23R:IL-23, which opened the way to evaluate a peptide macrocycle described in the literature as disrupter of this autoimmune target. Thus, the characterization of the interactions of this chemotype by HDX-MS in combination with computational approaches was achieved. To our knowledge, this is the first reported structural evidence regarding the site where a small compound binds to IL-23R.
RESUMEN
SETD8 is the methyltransferase responsible for monomethylation of lysine at position 20 of the N-terminus of histone H4 (H4K20). This activity has been implicated in both DNA damage and cell cycle progression. Existing biochemical assays have utilized truncated enzymes containing the SET domain of SETD8 and peptide substrates. In this report, we present the development of a mechanistically balanced biochemical assay using full-length SETD8 and a recombinant nucleosome substrate. This improves the binding of SAM, SAH, and sinefungin by up to 10,000-fold. A small collection of inhibitors structurally related to SAM were screened and 40 compounds were identified that only inhibit SETD8 when a nucleosome substrate is used.
