Sea of Hypotheses

the CamShaft wags the Whale
Whaleview of Camshaft

The CamShaft


ll (genetic) roads lead to helix 466-496, at least as I see it. Or, in the words of Dylan Thomas, it is "The force that through the green fuse drives the flower." This element runs through the "lower jaw" and undergoes a large structural change between the ADP.BeF and ADP.Vanadate structures from Rayment's group (though it should be pointed out that these structures are of a truncated motor; the ends of the molecule may be "unconstrained" since the sequences they normally abut are missing. However, it is clear that the "preferred" shape of the helix is different in the two structures, as shown below (structures aligned using residues 466-478)

BeF (Blue) and Vanadate (Purple) structure of Dictyostelium; Helix 466-496; the orientation is as if the "whale" is facing to the left and we rolled it onto its right side to see its belly.


What do we intend to do about it?


t present, a direct frontal assault is underway. Matt Scholz is looking for suppressors of Y494K and W501L, and most other suppressor hunts in the lab include mutagenesis of the region from amino acids 400-600. Our long -term goal is to identify essentially all the changes in the CamShaft and surrounding structures that can mutate to suppressors of other myosin mutations. Thus in the end, we intend to have a web of positions in the camshaft that contribute to common functions and the types of changes they must undergo to compensate for other mutations. From here, we will attempt to deduce the actual shapes and positions of the CamShaft at different points in the motor cycle!

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Bruce Patterson
http://research.biology.arizona.edu/myosin