IBEC Seminar: Carlos Moreno Yruela
viernes, julio 19 @ 10:00 am–11:00 am
Semi-synthetic nucleosomes to stabilize and image enzyme-chromatin interactions
Carlos Moreno Yruela, Researcher in Chemical Biology, EPFL, Switzerland
Chromatin structure regulates gene expression and is tightly controlled by histone post-translational modifications. SIRT7 is a histone lysine deacylase found to maintain oncogenic gene expression profiles supporting tumor growth and
metastasis. Interestingly, the activity of SIRT7 is fully dependent on binding to nucleosomes within chromatin. This feature has limited the development of inhibitors and chemical probes to further dissect its role in cancer progression. Here, we develop nucleosome-based tools for structural characterization and high-throughput screening. Thanks to 2- and 3-fragment native chemical ligation methods, we introduced synthetic peptides into the structure of histone H3, to install either mechanism-based thiourea crosslinkers or fluorescence quenchers at the positions of known SIRT7 substrates. First, mechanism-based crosslinking nucleosomes allowed us to stabilize the interaction of SIRT7 with its nucleosome substrates and obtain structures by cryoEM. The different complexes revealed a multivalent and non-canonical nucleosome binding mechanism, and specific residues responsible for targeting different substrates within the nucleosome. Second, nucleosomes with acyllysine fluorescence quenchers and a neighboring fluorophore proved to be SIRT7-activated fluorogenic substrates and will be used for high-throughput screening and single-molecule biophysical characterization. All in all, we developed a strategy to stabilize enzyme-chromatin interactions for detailed structural studies, as well as a platform for the development of translatable SIRT7-targeting cancer therapeutics.
Carlos studied Chemistry at the University of Zaragoza and obtained his M.Sc. in Drug Discovery from the University of Surrey (UK). He obtained his Ph.D. in Chemical Biology from the University of Copenhagen in 2019, on the development of assays and chemical probes for histone deacetylases in the laboratory of Prof. Christian Adam Olsen. He stayed 3 more years in Copenhagen as postdoctoral fellow, working on the newly found lactyl-lysine modification of histones. In 2022, Carlos moved to EPFL Lausanne (Switzerland) thanks to a postdoctoral grant from the Independent Danish Research Council, where he uses protein semi-synthesis to generate complex in vitro systems for translatable biophysical studies and anticancer drug development. Carlos is now an independent postdoctoral fellow of the Swiss National Science Foundation.
