Isolated auto-citrullinated regions of PADI4 associate to the intact protein without altering their disordered conformation.

Autor: Neira JL; IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain. Electronic address: jlneira@umh.es., Rizzuti B; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain; CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, 87036 Rende, Italy., Abian O; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain., Velazquez-Campoy A; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain.
Jazyk: angličtina
Zdroj: Biophysical chemistry [Biophys Chem] 2024 Sep; Vol. 312, pp. 107288. Date of Electronic Publication: 2024 Jun 29.
DOI: 10.1016/j.bpc.2024.107288
Abstrakt: PADI4 is one of the human isoforms of a group of enzymes intervening in the conversion of arginine to citrulline. It is involved in the development of several types of tumors, as well as other immunological illnesses, such as psoriasis, multiple sclerosis, or rheumatoid arthritis. PADI4 auto-citrullinates in several regions of its sequence, namely in correspondence of residues Arg205, Arg212, Arg218, and Arg383. We wanted to study whether the citrullinated moiety affects the conformation of nearby regions and its binding to intact PADI4. We designed two series of synthetic peptides comprising either the wild-type or the relative citrullinated versions of such regions - i.e., a first series of peptides comprising the first three arginines, and a second series comprising Arg383. We studied their conformational properties in isolation by using fluorescence, far-ultraviolet (UV) circular dichroism (CD), and 2D 1 H NMR. Furthermore, we characterized the binding of the wild-type and citrullinated peptides in the two series to the intact PADI4, by using isothermal titration calorimetry (ITC), fluorescence, and biolayer interferometry (BLI), as well as by molecular docking simulations. We observed that citrullination did not alter the local conformational propensities of the isolated peptides. Nevertheless, for all the peptides in the two series, citrullination slowed down the kinetic k off rates of the binding reaction to PADI4, probably due to differences in electrostatic effects compared to the presence of arginine. The affinities of PADI4 for unmodified peptides were slightly larger than those of the corresponding citrullinated ones in the two series, but they were all within the same range, indicating that there were no relevant variations in the thermodynamics of binding due to sequence effects. These results highlight details of the self-citrullination of PADI4 and, more generally, of possible auto-catalytic mechanisms taking place in vivo for other citrullinating enzymes or, alternatively, in proteins undergoing citrullination passively.
Competing Interests: Declaration of competing interest The authors do not have anything to declare. They do not have any conflict de interest.
(Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: