Vortrag  |  Kolloquien  |  Physik  |  Chemie

Tobacco mosaic virus-based nanotubular architectures: novel shapes and functionality through synthetic plant virology

Donnerstag, 12. Dezember 2019
17:00 – 18:00 Uhr


Clemens Bechinger

Christina Wege, Universität Stuttgart

The RNA-guided self-assembly of tobacco mosaic virus (TMV)-based nanotube systems with multivalent protein shells (diameter: 18 nm) enables to design and fabricate uncommon straight, kinked and branched architectures in vitro. A bidirectional growth of helical, stiff TMV-like nucleoprotein particles is initiated efficiently by Origin of Assembly (OAs) sequences in RNA, which recruit TMV coat protein (CP) to elongate nascent tubes bidirectionally from OAs nucleation sites. The RNA length determines the final aspect ratio of the resulting particles, and gets stably encapsidated into the robust CP helix. By way of tailored RNA with multiple OAs, assemblies with 700 CPs per 100 nm tube can be generated to contain domains in angular orientations of boomerang, tri- or tetrapod shape. Nanoparticle growth on immobilized RNA is possible as well and yields 'nanostick' or colloidal 'nanostar' arrays, or tetrahedrally expanded structures if connected with organic cores. Engineered TMV CPs displaying reactive groups can be integrated into the tubes either in even distributions, or in longitudinal 'Ianus particle' layouts. Thus, TMV-based nano- and mesoscale assemblies can serve as biological carrier scaffolds with high surface densities of selectively addressable coupling sites for a spatially ordered display of molecule ensembles. They represent a new class of hybrid nano- to mesoscale scaffolds useful in spatial and structural designer layouts for various applications. As we found out that biomolecules such as enzymes can profit from an immobilization on TMV with unexpectedly increased stability and reusability, TMV 'adapter scaffolds' have been evaluated in enzyme-based biosensors. Both indirect and direct (electrochemical, label-free) detection of glucose or antibiotics profit from TMV adapters substantially, in that these convey highest sensitivities and detection ranges, fastest response times and reduced noise. TMV-assisted penicillin sensors even retained near-constant performance over at least one year. Other tests revealed long-lasting scalable effects of TMV additives on the magnetoviscosity of ferrofluids, or on the tissue targeting of TMV-like nanorods in mice, in dependence of both the particles' aspect ratio and their outer surface charge and/or display of functional peptides. Many further layouts may be enabled by synthetic TMV-based hybrid structures, with a realistic potential for fundamental research and applications in novel 'smart materials', due to the high availability and easy handling of the natural, plant-made viral building blocks.

Recent Review: Wege, C., Koch, C. (2019). From stars to stripes: RNA-directed shaping of plant viral protein templates—structural synthetic virology for smart biohybrid nanostructures. WIREs Nanomed Nanobiotechnol.;e1591, https://doi.org/10.1002/wnan.1591