title: Theory of force-extension curves for modular proteins and DNA hairpins.
abstract: We study a model describing the force-extension curves of modular proteins, nucleic acids, and other biomolecules made out of several single units or modules. At a mesoscopic level of description, the configuration of the system is given by the elongations of each of the units. The system free energy includes a double-well potential for each unit and an elastic nearest-neighbor interaction between them. Minimizing the free energy yields the system equilibrium properties whereas its dynamics is given by (overdamped) Langevin equations for the elongations, in which friction and noise amplitude are related by the fluctuation-dissipation theorem. Our results, both for the equilibrium and the dynamical situations, include analytical and numerical descriptions of the system force-extension curves under force or length control and agree very well with actual experiments in biomolecules. Our conclusions also apply to other physical systems comprising a number of metastable units, such as storage systems or semiconductor superlattices.
authors.affiliation: G. Millán Institute, Fluid Dynamics, Nanoscience and Industrial Mathematics, Universidad Carlos III de Madrid, 28911 Leganés, Spain.
authors.forename: L L
authors.initials: LL
authors.lastname: Bonilla
authors.affiliation: Departamento de Matemática Aplicada, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Carpio
authors.affiliation: Física Teórica, Universidad de Sevilla, Apartado de Correos 1065, E-41080, Sevilla, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Prados
mesh_terms: D001696:Biomechanical Phenomena; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055029:Inverted Repeat Sequences; D055595:Mechanical Phenomena; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D055550:Protein Stability; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D013696:Temperature
chemical_list: D011506:Proteins; D004247:DNA