Bacterial motors carefully studied; a review of kinesins (Introduction)

by David Turell , Wednesday, October 09, 2024, 19:11 (44 days ago) @ David Turell

Kinesins are amazingly complex:

https://evolutionnews.org/2024/10/kinesins-nanoscale-molecular-motors-each-built-for-a-...

"Typically, kinesins are built with 1) a set of motor domains responsible for harnessing the energy from ATP and generating force, 2) a central stalk domain that holds the motor domains together, and 3) a tail domain with specialized functions for binding different cargo.

"What is amazing about kinesins is they all get their energy from the same place (ATP hydrolysis), but they seem to use it differently for different tasks inside the cell. Some kinesins are power walkers (like the one in the video above) — taking hundreds of steps along the microtubule before falling off. Others are hoppers — only taking a few steps before letting go of the track. Some kinesins walk forward, some walk backward, and some walk in both directions (trust me…this observation is still quite puzzling from a biophysical perspective). Other kinesins don’t walk at all, but somehow use their ATP energy to trigger the microtubule track to fall apart underneath them.

"Are these differences in function a result of random haphazardness — stochastic tweaking of gene sequences to give infinitesimally small perturbations of amino acids within the motor to eventually (over billions and billions of years) produce a smorgasbord of elegant machines like the kinesin family? Many in the scientific community have faith in this hopeless Darwinian theory. Thankfully, there are a number of scientists who view the nanoscale world with wonder and are open to the idea that molecular machines reflect purpose and design. They see molecular motors as intelligently designed for a reason. These machines must function properly for cells to divide, for essential cargo to be delivered, for biochemical energy to be converted from chemical gradients into stored energy for metabolism, for the propulsion of a cell in a given direction to avoid danger."

Comment: there are many videos available to see kinesins in action walking along the tubules while carrying a cargo. All constructed from amino acids in various folding patterns. dhw to the contrary, this is the proper level for discussion of cellular activity.