User:Andy Maloney/Notebook/Lab Notebook of Andy Maloney/2009/04/15/Kinesin and µ-tubules

Disclaimer

Below are my thoughts and review on the paper I read. In no way should my ideas or opinions be construed as being correct. They shouldn't be used as a "Cliff's Notes" to the paper either. Read it before you read my notes.

Paper

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Review

Koch was right when he said Block papers are awesome.

• They talk about coating microspheres and how coated microspheres enhance kinesin to walk along microtubules.
  • I'm not sure I understand this. I think all they mean to say is that, they prevented exposed silica on the microspheres from electrostatically being repelled from the microspheres. Coating the beads with either Casein and Cytochrome C or Bovine Serum Albumin helped facilitate kinesin getting close enough to attach to a microtubule.
• Experiment
  • They caught a bead with an optical tweezer.
  • They brought the bead close to a microtubule and then turned off the tweezers. There are 4 outcomes when doing this:

1. The bead failed to bind to the microtubule even after repeated attempts to get it to do so.
2. The bead bound to the microtubule for several seconds with no movement or it did move but not far enough.
3. The bead bound to the microtubule but it didn't reach the end of it.
4. The bead bound to the microtubule and it reached the end of it.

• This experiment did what I hoped the Ishiwata experiment did, it let the kinesin attach to microtubules naturally without hoping it did.
• For each of the 4 outcomes above, they tested the number of kinesin attached to a microsphere and noted what percentage of the microspheres exhibited each outcome.

• They also used the optical tweezers to determine a lower bound on the trapping stiffness necessary to not interfere with kinesin walking along microtubules, ~< 5 pN.
• They noted that the kinesin speed was about 0.35 - 0.45 µm/s.

Take home

Well, the best take home from this is that if I need something answered, I should read a Block paper. The best thing to note here is that they figure out the method for coating microspheres and how to attach only one kinesin molecule per microsphere.

They also state a lower bound for optical tweezer stiffness so that it doesn't interfere with kinesin motility.