Biology subjects

Thore, S.

Publications and source records attributed to Thore, S..

3 recordsLinked to original sources

bioRxiv2025

Helical foldamers as selective G-quadruplex ligands

We investigated the G-quadruplex binding selectivity of short aromatic oligoamide helical foldamers comprising quinoline (Q) and pyridine (P) units. We found that the foldamers prefer parallel G-quadruplex structures, especially when the external G-quartets are sterically accessible. A crystal structure of the tetramer QQPQ with the parallel G-quadruplex formed by dTGGGTTGGGTTGGGTTGGGT shows two quinoline subunits interacting with an external G-quartet through {pi}-stacking, and solution NMR confirms that the foldamer targets the 3 and 5 ends of this G-quadruplex. Foldamers can also selectively target sequence variants of the telomeric sequences containing adenine-to-thymine mutation in the loops. The conformational selectivity of foldamers originates from the bulkiness of oligomers with four or more subunits, which imposes steric restrictions on G-quadruplex binding. The flexibility provided by the pyridine subunits was also key to improve affinity. Mixed quinoline-pyridine foldamers are thus a promising class of selective G-quadruplex ligands, and their unique modular scaffold offers new avenues to further improve their affinity and selectivity.

biophysics↗

bioRxiv2023

Molecular details of the CPSF73-CPSF100 C-terminal heterodimer and interaction with Symplekin

Eukaryotic pre-mRNA is processed by a large multiprotein complex to accurately cleave the 3 end, and to catalyze the addition of the poly(A) tail. Within this cleavage and polyadenylation specificity factor (CPSF) machinery, the CPSF73 endonuclease subunit directly contacts both CPSF100 and the scaffold protein Symplekin to form a subcomplex known as the core cleavage complex (CCC) or mammalian cleavage factor (mCF). Here we have taken advantage of a stable CPSF73-CPSF100 minimal heterodimer from E. cuniculi to determine the solution structure formed by the first and second C-terminal domain (CTD1 and CTD2) of both proteins. We find a large number of contacts between both proteins in the complex, and notably in the region between CTD1 and CTD2. A similarity is also observed between CTD2 and the TATA-box binding protein (TBP) domains. Separately, we have determined the structure of the terminal CTD3 domain of CPSF73, which also belongs to the TBP domain family and is connected by a flexible linker to the rest of CPSF73. Biochemical assays demonstrate a key role for the CTD3 of CPSF73 in binding Symplekin, and structural models of the trimeric complex from other species allow for comparative analysis and support an overall conserved architecture.

biochemistry↗

bioRxiv2020

Leigh Syndrome-inducing Mutations Affect LRPPRC / SLIRP Complex Formation

Mitochondria are essential organelles carrying their own genetic information which require specific gene expression processes. The leucine rich pentatricopeptide protein (LRPPRC) and its partner the SRA stem-loop interacting RNA binding protein (SLIRP) form a stable complex implicated in mRNA stability and polyadenylation. LRPPRC/SLIRP complex formation is still poorly characterized. We demonstrate that SLIRP interacts with the N-terminal region of LRPPRC in a RNA independent manner. We further show that the complex is stable in presence of high salt concentration. Point mutation and deletions found in the LRPPRC protein and responsible for the French-Canadian Leigh Syndrome (LSFC) are shown to affect complex formation in vitro. Our data are identifying the key region of LRPPRC involved in SLIRP association and showing the direct consequence of various LSFC mutations on the complex formation. Further experiments aiming at deciphering LRPPRC/SLIRP function(s) in vivo will benefit from our functional domain characterization.

biochemistry↗