iSCAT – a new approach for visualizing biological structures and dynamics
Event details
| Date | 01.02.2017 |
| Hour | 16:30 › 17:30 |
| Speaker | Dr. Joanna Andrecka, University of Oxford |
| Location | |
| Category | Conferences - Seminars |
Abstract:
Dramatic developments in fluorescence microscopy over the past decades have enabled routine studies down to the single molecule level and structural observations far beyond the limits defined by diffraction. Despite its many advantages, the fundamental limitation of fluorescence detection is the frequency with which photons can be emitted and thus detected. The result is a considerable gap between the rate at which dynamics can be recorded and the underlying speed of motion on the nanoscale. iSCAT (interferometric scattering microscopy) is an alternative approach that relies on efficient detection of light scattering. iSCAT is capable of following the motion of nanoscopic labels (e.g. gold nanoparticles) with true nanometer precision down to the microsecond regime. Using this technique has enabled us to address a surprising variety of fundamental questions in biophysics.
First, I will present an example of using iSCAT for single particle tracking; the technique was used in order to follow myosin-5 motion. By precise tracking of the head of myosin-5, a rotation of its N-terminal domain during the power stroke was revealed. Moreover, it was shown that, in contradiction to the three-dimensional Brownian search hypothesis, the detached head occupies a single off-actin transient state and reaches the desired binding site in a highly controlled manner. Second, I will show that iSCAT can be used for ultra-sensitive imaging of biological structures such as lipid vesicles, lipid membranes or filaments without any need for labelling. The label free approach can be extended all the way down to the single protein level and I will present a movie of unlabeled myosin 5 moving along an actin filament. Finally, I will introduce a new concept of using iSCAT, in combination with fluorescence detection and “classic” structural biology methods, to understand how structural changes in macromolecular machines enable and regulate their cellular functions.
Dramatic developments in fluorescence microscopy over the past decades have enabled routine studies down to the single molecule level and structural observations far beyond the limits defined by diffraction. Despite its many advantages, the fundamental limitation of fluorescence detection is the frequency with which photons can be emitted and thus detected. The result is a considerable gap between the rate at which dynamics can be recorded and the underlying speed of motion on the nanoscale. iSCAT (interferometric scattering microscopy) is an alternative approach that relies on efficient detection of light scattering. iSCAT is capable of following the motion of nanoscopic labels (e.g. gold nanoparticles) with true nanometer precision down to the microsecond regime. Using this technique has enabled us to address a surprising variety of fundamental questions in biophysics.
First, I will present an example of using iSCAT for single particle tracking; the technique was used in order to follow myosin-5 motion. By precise tracking of the head of myosin-5, a rotation of its N-terminal domain during the power stroke was revealed. Moreover, it was shown that, in contradiction to the three-dimensional Brownian search hypothesis, the detached head occupies a single off-actin transient state and reaches the desired binding site in a highly controlled manner. Second, I will show that iSCAT can be used for ultra-sensitive imaging of biological structures such as lipid vesicles, lipid membranes or filaments without any need for labelling. The label free approach can be extended all the way down to the single protein level and I will present a movie of unlabeled myosin 5 moving along an actin filament. Finally, I will introduce a new concept of using iSCAT, in combination with fluorescence detection and “classic” structural biology methods, to understand how structural changes in macromolecular machines enable and regulate their cellular functions.
Practical information
- Expert
- Free
- This event is internal
Organizer
- Prof. Benoit Deveaud, Institute of Physics
Contact
- Blandine Jérôme