You Are Interested in Studying Kinesin Movements

question 13

Essay

You are interested in studying kinesin movements.You therefore prepare silica beads and coat them with kinesin molecules so that each bead, on average, has only one kinesin molecule attached to it.You add these kinesin-coated beads to a preparation of microtubules you have polymerized.Using video microscopy, you watch the kinesin [labeled with green fluorescent protein (GFP)] move down the microtubules.
A.Kinesin-GFP has been measured to move along microtubules at a rate of 0.3 μm/sec, and single-molecule studies have revealed that kinesin moves along microtubules progressively, with each step being 8 nm.How many steps can the kinesin molecule take in 4 seconds, assuming that the kinesin stays attached to the microtubule for the entire 4 seconds?
B.Because each kinesin molecule is thought to take approximately 100 steps before falling off the microtubule, will you see your silica beads detach from the microtubule during your 4 seconds of observation?
C.What would you predict would happen to the kinesin-coated silica beads if you were to add AMP-PNP (a nonhydrolyzable ATP analog)?