9-26-00: Added Three Musketeers (494-501-691) data and models to "Solving the Cycle"

Making Myosin Mutants: an Approach to Understanding the Little Bitty Motor that moves you

Note: the beef is toward the bottom of ithis page under 'solving the cycle'-it's a compendium of all our mutant-interaction data. As is explained in the earlier sections, these represent pieces of a puzzle whose solution will be a 'movie' of the myosin motor BEING a motor...

e are striving to make sense of a very small and powerful motor: a molecular machine that drives muscle contraction, cell division and a variety of other processes in non-bacterial cells. Our approach is to isolate damaged (mutant) versions of the motor and try to deduce why changing the motor at a given point causes it to function improperly. We then hunt for "repaired" versions of these motors. The location and behavior of the repair event will hopefully lead us to a mechanical understanding of how and why the myosin protein is a motor. In short, we're trying to figure out what the parts are and what forces are acting to induce the motor to go through its cycle (e.g. in an internal combustion engine, the ignition and explosion of fuel, regulated by the valves, drives the pistons which are connected eventually to the axles).

I've tried to make this page accessible to pretty much anybody who wants to think or learn about the problem we work on; this may alternately frustrate experts and fail to satisfy newcomers. Your comments can help me. Each page has a color theme; to help you remember where info is. There's a navigation table at the bottom of most pages with likely places to go next; the Monster Truck will always bring you Home (this page). In the list below, sections with icons take you to specific info while those that are text-only lead to another page of descriptions and choices. Text in green gives a more technical description of content.

Philosophy: Is there really any hope of getting clues about how a tiny machine works by breaking it? And what hope is there of trying to fix it by breaking it some more? For the philosophy behind our approach of mutant making and suppressor isolation as an approach to enlightenment, delve into this page. Rationale.

Introductory Stuff--Follow this link to go to a directory that will guide you through the basic workings of the myosin motor and the odd nomenclature used on these pages to refer to the 3-D structure of a 'frozen' myosin motor. Newly added Amino Acid Theatre lets you explore amino acid structures and compare them. Biochemical summary of cycle.

How do they DO that?--Follow this link to go to a directory that will guide you through the basic methodologies we use--from isolating mutants to learning the properties of defective motors. Mutant isolation, biochemical characterization.

A Specific Example: Follow this link to go to a directory that will walk you through our work with one specific mutant motor. You'll see how we have deduced a model for what's wrong with the motor and how we're using mutant hunting to test and extend our proposal. Genetic and biochemical analysis of G680V mutant.

the Sea of Hypotheses (all hope abandon, ye who enter!). Does any of this genetic mucky-muck help us understand how the motor works? To see how we're integrating biochemistry, suppressor genetics, and sheer guesswork to solve the " riddle wrapped in a mystery inside an enigma," visit the Sea of Hypotheses, where hopes and dreams--and plans of attack--are revealed. Models for motor movement, faults of mutants, suppressors.

Solving the Cycle The Y2K direction of this work is an initiative to boldly go where no genetics has gone before: Deducing and ordering the shapes of the motor through its cycle. This work builds on all our findings to date, emerging hypotheses and accumulated wisdom (such as it is!). Follow the link for the rationale, the approach, and the emerging picture of an orderly, well-behaved Myosin! (Currently under construction, but there's enough there to sink your teeth into). Being expanded and updated as time and new data permit! Summary of mutants isolated, genetic interactions observed; functional relationships between mutants

Hot new stuff! Added our latest genetic and intellectual data concerning three highly conserved residues that form a cluster in most crystal structures and which each showed up as cold-sensitive mutants in our initial genetic screen. Follow this link to get right to the meat of the problem (or go straight to our working model).

Whodunit? Despite the liberal use of the word "I" in this document (mostly to denote lack of responsibility of others for harebrained ideas) this work is very much a team effort. A short credit list appears on the next page. Most of the stuff in these pages was generated by a variety of commercial, shareware and freeware sources. In the giving credit where it's due dept. there's WhoDunIt.

Ye Olde Stuffe: Pages that were once an active part of the site, but have been 'retired'. Kept just in case anybody used them...

Care to Comment? I'd be most curious to know what you thought of the ideas and presentation here. The link to my name in the footer will address an e-letter to me.

Bruce Patterson