Transcript Chapter22 - Extras Springer

Figure 22.1: During its power stroke, Myosin exerts a force on an actin filament, propelling the motor to the left. Scale bar = 6
nm. (From R. D. Vale and R. A. Milligan, Science 288, 88 (2000) by permission of the American Association for the
Advancement of Science.)
Figure 22.2: Kinesin steps forward, transporting its cargo toward the plus end of a microtubule. Scale bar = 4 nm. Figure
from Vale and Milligan (2000). (From R. D. Vale and R. A. Milligan, Science 288, 88 (2000) by permission of the
American Association for the Advancement of Science.)
Figure 22.3: A depiction of F0F1-ATP Synthase. The free energy of high proton concentrations is used to generate ATP from ADP
by mechanically coupling proton movement to conformational changes in the protein.
Figure 22.4: A sequence of double stranded DNA containing a six nucleotide sequence (shown in boldface) recognized by the
restriction enzyme EcoRI. The action of EcoRI is to cut the strands as indicated, making “sticky ends” which have a high
affinity for their complements. Mixture of two different strands cut by the same restriction enzyme can result in chimeras:
sequences containing DNA from two different sources
Figure 22.5: Insertion of the F1-ATPase gene into a plasmid. The gene encoding the motor is flanked by two restriction enzyme sites,
BamHI and PstI. The plasmid pQE-30 contains a number of restriction sites, including BamHI and PstI and a gene encoding for
ampicillin resistance (Ampicillin is a potent anti-bacterial agent). Incubation of the gene and the plasmid with the restriction enzymes
results in some new plasmids containing the ATPase gene. Insertion of these plasmids into cells and growth of these cells in media
containing ampicillin selects only cells containing the new genes. Addition of IPTG to the cell culture induces expression of the genes
after the lac promoter, in this case, the genes encoding the , , and  subunits of F1-ATPase.
Figure 22.6: Laser tweezer position measurements of kinesin stepping along a microtubule. Constant force feedback moves the
optical trap as the motor moves, maintaining a constant displacement of the bead from the trap center. 8 nm steps can be seen.
(From K. Visscher, M. J. Schnitzer, and S. M. Block, Nature 400, 6740 (1999) by permission of Nature Publishing Group.)
Figure 22.7: (a) Darkfield images of gold beads attached to the rotor of F1-ATPase. Centroid positions are shown above the
images at 3x magnification. The interval between images is 0.5 ms. (b) Rotation versus time at 2mM ATP. (From Ref. 3 by
permission of Nature Publishing Group.)
Figure 22.8: Patterned “ratchets” sort microtubules. Due to asymmetrically patterned photoresist, microtubules entering
the triangular area exit to the right irrespective of their side of entry. This results in aligned and oriented microtubules.
(From Ref. 42 by permission of the Biophysical Society.)
Figure 22.9: Left: Depiction of an assembled hybrid biomolecular nanodevice based on the rotary motor F1-ATPase (not to
scale). Right: Exploded view showing all structural and linking components. The device self-assembles in multiple steps.