title: Interplay between the mechanics of bacteriophage fibers and the strength of virus-host links.
abstract: Viral fibers play a central role in many virus infection mechanisms since they recognize the corresponding host and establish a mechanical link to its surface. Specifically, bacteriophages have to anchor to bacteria through the fibers surrounding the tail before starting the viral DNA translocation into the host. The protein gene product (gp) 37 from bacteriophage T4 long tail fibers forms a fibrous parallel homotrimer located at the distal end of the long tail fibers. Biochemical data indicate that, at least, three of these fibers are required for initial host cell interaction but do not reveal why three and no other numbers are required. By using atomic force microscopy, we obtained high-resolution images of gp37 fibers adsorbed on a mica substrate in buffer conditions and probed their local mechanical properties. Our experiments of radial indentation at the nanometer scale provided a radial stiffness of ∼ 0.08 N/m and a breaking force of ∼ 120 pN. In addition, we performed finite element analysis and determined a Young's modulus of ∼ 20 MPa. From these mechanical parameters, we hypothesize that three viral fibers provide enough mechanical strength to prevent a T4 virus from being detached from the bacteria by the viral particle Brownian motion, delivering a biophysical justification for the previous biochemical data.
authors.affiliation: Nanotec Electrónica S.L., Ronda de Poniente, 12-2 C, 28760 Tres Cantos, Madrid, Spain and Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain and IFIMAC, Centro de Investigación de Física de la Materia Condensada, 28049 Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Ares
authors.affiliation: Departamento de Estructuras de Macromoléculas, Centro Nacional de Biotecnología (CNB-CSIC), calle Darwin 3, 28049 Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Garcia-Doval
authors.affiliation: Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain and IFIMAC, Centro de Investigación de Física de la Materia Condensada, 28049 Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Llauró
authors.affiliation: Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain and IFIMAC, Centro de Investigación de Física de la Materia Condensada, 28049 Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Gómez-Herrero
authors.affiliation: Departamento de Estructuras de Macromoléculas, Centro Nacional de Biotecnología (CNB-CSIC), calle Darwin 3, 28049 Madrid, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: van Raaij
authors.affiliation: Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain and IFIMAC, Centro de Investigación de Física de la Materia Condensada, 28049 Madrid, Spain.
authors.forename: P J
authors.initials: PJ
authors.lastname: de Pablo
mesh_terms: D017122:Bacteriophage T4; D055119:Elastic Modulus; D020342:Finite Element Analysis; D054884:Host-Pathogen Interactions / Q000502:physiology*; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014764:Viral Proteins