Year: 2026
Type: article
Abstract: The Polycomb repressive complexes can be considered a paradigm of chromatin-based gene regulation in animals. Two of the proteins involved in such complexes are the Ring finger protein 1 (RING1) and the intrinsically disordered protein RING1A and YY1 binding protein (RYBP), which binds to RING1 in some of the Polycomb complexes. Peptidyl arginine iminohydrolases (PADIs) are enzymes involved in the post-translational modification of arginine to citrulline. PADI4, one of the five isoforms of PADI in humans, citrullinates RING1B and RYBP at specific arginines at their C-terminal (Arg231) and N-terminal (Arg53) regions, respectively. In this work, we studied in vitro and in silico whether isolated peptides from each protein, encompassing those wild-type arginines and their citrulline-modified counterparts, were capable of binding to PADI4. The isolated peptides, either in wild-type or modified form, were monomeric and disordered as indicated by far-UV CD and NMR. The affinity constants of peptides for PADI4, as measured by fluorescence, biolayer interferometry (BLI) and isothermal titration calorimetry (ITC), were in the low micromolar range (dissociation constants around 10-20 μM), and the affinities were smaller for the citrullinated variants. Molecular docking simulations showed that the isolated peptides from each protein, either in wild-type form or modified variants, targeted the active site of PADI4, corresponding to the catalytic residue Cys645. These findings suggest that the isolated peptides were capable of binding to the enzyme with affinities similar to those of intact RING1B or RYBP, and that citrullination of the arginines diminished the affinity for the enzyme.
Institutions: Universitat de Miguel Hernández d'Elx, University of Calabria, Universidad de Zaragoza, Instituto de Biocomputación y Física de Sistemas Complejos, Centro de Investigacion Principe Felipe, Centro de Investigación Biomédica en Red, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Instituto de Investigación Sanitaria Aragón
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,170
Funders: Ministerio de Ciencia, Innovación y Universidades, European Commission, Generalitat Valenciana, HORIZON EUROPE Framework Programme, European Regional Development Fund, Agencia Estatal de Investigación, Conselleria de Cultura, Educación y Ciencia, Generalitat Valenciana, Ministerio de Universidades
Awards: G1105844351, G1175115578, G1400335870, G1422035950, G1622782223, G2094515880, G210041235, G2262748287, G2597806754, G2601397997, G300979063, G3220251042, G34346518, G3452381487, G3480869486, G3565621276, G3681454997, G3825317807, G3857581125, G3961433376, G4042783231, G410571670, G425668148, G451917667, G4526231891, G491712853, G5080475149, G5154704155, G5195188938, G5404395142, G5539308778, G5540489325, G5635532810, G5903000213, G5945436923, G5967599077, G624877701, G6768778611, G7084143925, G717256432, Unlocking the Hidden Treasures of Aquatic Extremophiles: sustainable development of industrially relevant novel active biomolecules., G7434936867, G7805626310, G7863371703, G792975244, G8497050386, G861793060, G929308097
OpenAlex ID: W7172267791