To further examine the relationship of Band 3 and spectrin (and
more generally, of integral membrane proteins and the peripheral
membrane proteins of the cytoskeleton), the markers were reversed:
that is, the latex bead was attached through the membrane to spectrin
and gold was attached to Band 3 proteins. Initially, 3 gold particles
are visible in the video sequence (a third one is located on the
upper right edge of the ghost).
The video sequence is divided into 3 episodes: 1. during the first
6 sec, the behavior of unmanipulated particles are displayed (and
may be compared with your observations in earlier videos); then,
the optical tweezers are used to pull the latex particle from right
to left at a rate of almost 2 mm/sec; during the final episode,
the force field is reversed and the bead is returned more or less
to its original location. The video lasts 20 sec and is projected
at about the rate it was recorded; therefore the movements you observe
are real time.
Watch the video in the left compartment, review earlier videos
in the right, and consider the questions; then continue to next
problem to examine the results of a Control experiment.
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