Kinesin & AMP-PNP: The Movie

This movie was made by differential interference contrast video light microscopy.  It shows an experiment from the paper
 

In this experiment, we see a single molecule of the biotinated kinesin derivative K448-BIO moving along a microtubule (the faint, nearly vertical line in the background).  The kinesin molecule is labeled with a 100 nm, streptavidin conjugated polystyrene bead to render it visible in the microscope.  The solution contains 1 mM ATP, kinesin's substrate, together with 1 mM AMP-PNP, an ATP analog that is a kinesin inhibitor.  In this experiment, it is possible to detect the binding of AMP-PNP to the single kinesin molecule moving the bead, because such inhibitor binding results in a detectable pause in the movement of the kinesin-bead conjugate.  When AMP-PNP is subsequently released, movement is resumed.  Such single-molecule experiments permit us to elucidate enzyme mechanisms and measure the kinetics of single reaction steps under normal, steady-state turnover conditions.

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Movies of single-molecule biophysics experiments