An integrated multi-wavelength SCATTIRSTORM microscope combining TIRFM and IRM modalities for imaging cellulases and other processive enzymes

We describe a multimodal SCATTIRSTORM microscope for visualizing processive enzymes moving on immobilized substrates. The instrument combines Interference Reflection Microscopy (IRM) with multi-wavelength Total Internal Reflectance Fluorescence Microscopy (TIRFM). The microscope can localize quantum dots with a precision of 2.8 nm at 100 frames/s, and was used to image the dynamics of the cellulase, Cel7a interacting surface-immobilized cellulose. The instrument, which was built with off-the-shelf components and controlled by custom software, is suitable for tracking other degradative enzymes such as collagenases, as well as motor proteins moving along immobilized tracks.