Single M13 bacteriophage tethering and stretching.
The ability to present biomolecules on the highly organized structure of M13 filamentous bacteriophage is a unique advantage. Where previously this viral template was shown to direct the orientation and nucleation of nanocrystals and materials, here we apply it in the context of single-molecule (SM) biophysics. Genetically engineered constructs were used to display different reactive species at each of the filament ends and along the major capsid, and the resulting hetero-functional particles were shown to consistently tether microscopic beads in solution. With this system, we report the development of a SM assay based on M13 bacteriophage. We also report the quantitative characterization of the biopolymer's elasticity by using an optical trap with nanometer-scale position resolution. Expanding the fluctuating rod limit of the wormlike chain to incorporate enthalpic polymer stretching yielded a model capable of accurately capturing the full range of extensions. Fits of the force-extension measurements gave a mean persistence length of approximately 1,265 nm, lending SM support for a shorter filamentous bacteriophage persistence length than previously thought. Furthermore, a predicted stretching modulus roughly two times that of dsDNA, coupled with the system's linkage versatility and load-bearing capability, makes the M13 template an attractive candidate for use in tethered bead architectures.
Khalil
Ahmad S
AS
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Ferrer
Jorge M
JM
Brau
Ricardo R
RR
Kottmann
Stephen T
ST
Noren
Christopher J
CJ
Lang
Matthew J
MJ
Belcher
Angela M
AM
D017104:Bacteriophage M13 / Q000378:metabolism*; D001696:Biomechanical Phenomena; D004247:DNA / Q000378:metabolism; D008954:Models, Biological
D004247:DNA