Molecular motors and ATP energy coupling


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The Hackney lab studies the mechanisms, regulation and structure of enzymes, with emphasis on the ways in which structure and mechanism are interrelated. Current research effort is centered on proteins that function as molecular motors, such as the conventional kinesin-1 ATPase, which moves a range of cargo molecules along tracks of microtubules from the interior of cells to the periphery.  A major goal is to account for the biophysical properties of kinesin, as a motor, based on its biochemical properties that couple the steps of ATP hydrolysis to the binding and conformational changes that produced movement and force, especially at the single molecule level. This study also relies heavily on single turnover experiments by stopped flow and FRET and other spectroscopic probes for binding and conformational changes. The rates in the hydrolysis direction have been determined, but it is much more difficult to determine the 'back' rates for ATP resynthesis because the hydrolysis reaction is so highly favored. An additional important approach is the use of isotopic exchange methods to determine these 'back' rates of ATP resynthesis that are needed to determine the free energy changes at each step.   Another area of emphasis is the regulation of kinesin.  Although each kinesin-1 has two motor domains and two tail domains, we discovered that only one of the two tail domains binds to the two motor domains to produce an autoinhibited 'half-site' complex.   In addition, many other ATPase-coupled machines have been discovered and investigation of their mechanism of action and regulation are being explored as new areas of focus.

 


 

Education

PhD 1975, University of California, Berkeley

Postdoctoral Training

University of California, Los Angeles


 

Department of Biological Sciences
Carnegie Mellon University

4400 Fifth Avenue
Pittsburgh, PA 15237

Phone: (412) 268-3244

E-mail: ddh@andrew.cmu.edu

Visit Hackney group website.