title: Concentrated Solutions of Single-Chain Nanoparticles: A Simple Model for Intrinsically Disordered Proteins under Crowding Conditions.
abstract: By means of large-scale computer simulations and small-angle neutron scattering (SANS), we investigate solutions of single-chain nanoparticles (SCNPs), covering the whole concentration range from infinite dilution to melt density. The analysis of the conformational properties of the SCNPs reveals that these synthetic nano-objects share basic ingredients with intrinsically disordered proteins (IDPs), as topological polydispersity, generally sparse conformations, and locally compact domains. We investigate the role of the architecture of the SCNPs in their collapse behavior under macromolecular crowding. Unlike in the case of linear macromolecules, which experience the usual transition from self-avoiding to Gaussian random-walk conformations, crowding leads to collapsed conformations of SCNPs resembling those of crumpled globules. This behavior is already found at volume fractions (about 30%) that are characteristic of crowding in cellular environments. The simulation results are confirmed by the SANS experiments. Our results for SCNPs--a model system free of specific interactions--propose a general scenario for the effect of steric crowding on IDPs: collapse from sparse conformations at high dilution to crumpled globular conformations in cell environments.
authors.affiliation: Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain.|Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain.
authors.forename: Angel J
authors.initials: AJ
authors.lastname: Moreno
authors.affiliation: Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain.
authors.forename: Federica
authors.initials: F
authors.lastname: Lo Verso
authors.affiliation: Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain.
authors.forename: Arantxa
authors.initials: A
authors.lastname: Arbe
authors.affiliation: Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain.|Departamento de Física de Materiales, Universidad del País Vasco (UPV/EHU) , Apartado 1072, E-20800 San Sebastián, Spain.|IKERBASQUE - Basque Foundation for Science, Alameda Urquijo 36, E-48011 Bilbao, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Pomposo
authors.affiliation: Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain.|Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 San Sebastián, Spain.|Departamento de Física de Materiales, Universidad del País Vasco (UPV/EHU) , Apartado 1072, E-20800 San Sebastián, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Colmenero
mesh_terms: D064267:Intrinsically Disordered Proteins / Q000737:chemistry*; D008958:Models, Molecular; D053758:Nanoparticles; D012996:Solutions
chemical_list: D064267:Intrinsically Disordered Proteins; D012996:Solutions