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.

RNA multiscale simulations as an interplay of electrostatic, mechanical properties, and structures inside viruses

“…In particular, the interactions generated at the atomistic and molecular resolutions are of predominant interests for non-enveloped and enveloped viruses [29,30,31,32,33,34,1,35]. For a few decades, the physical virology community has employed diverse experimental techniques, like force microscopy, to learn more about the mechanical and electrostatic properties of biomacromolecular systems [36,37,38,39,40,41,42,43,44,45,46]. However, the amount of viruses that are electrostatically characterized at the nanoscale (i.e.…”

“FAGOMA: Spanish Network of Bacteriophages and Transducer Elements”—V Meeting Report

“…This session, chaired by Dr. Mark van Raaij (CNB-CSIC, Madrid), began with his PhD student Mateo Seoane, who presented an overview of the crystal structures of several receptor-binding proteins and lytic enzymes from Escherichia , Salmonella , and Staphylococcus phages recently solved by their laboratory [5,6,7], including the structure of the coliphage T5 fibre pb1, a collaboration with Dr. Boulanger’s laboratory. Ongoing structural and binding analysis with receptors and receptor analogs from phages infecting bacteria with an economic or medical interest were also discussed.…”

Bacteriophage T4 long tail fiber domains

“…One possibility is that in the free phage, the LTFs cannot bend downwards very much due to steric hindrance. However, when attached to the cell by at least three LTFs (Ares et al 2014), the Brownian motion occasionally forces the phage away from the bacterium, and the proximal part of the stiff LTFs may be forced into a less favorable, more downward angle, leading to the gp9-gp34 complexes pushing against a switch in the baseplate. This switch involves the baseplate proteins gp10 and gp11, as depicted in Fig.…”