Research Interests:
The intricate organization and interaction of macromolecules in
striated muscles provides a unique system for the study of the coupling
of chemical energy to mechanical work. In my laboratory we are interested
in the relationship between changes in the structures and protein-protein
associations of the major contractile proteins (actin and myosin),
and their physiological functions. Actin forms a protein filament
scafold within muscle cells andmyosin is a mechano-enzyme that has
been identified as the molecular motor of striated muscle contraction.
Both of these proteins are found in all mammalian cells and involved
inprocess as diverse as cell division and the movement of intracellular
organelles.
As a tool in our studies of contractile protein function, we use
site-directed chemical modifications to perturb biochemical and
physiological responses and/or report on changes in the molecular
environment. Physiological measurements of muscle function include
force development, the velocity of muscle shortening, and dynamic
stiffness of muscle cells. In some studies, paramagnetic probes
are site-specifically attached to contractile proteins insitu and
Electron Paramagnetic Resonance Spectroscopy (EPR) is used follow
the orientation, motion and conformation of the labeled cytoskeletal
component. Biochemical assays are used to study effects of the chemical
modifications on energy utilization.
By combining spectroscopy with mechanical and biochemical data
we can relate molecular level information to the physiological responses
of skeletal muscle cells. The ultimate goal of our studies is to
gain insights into the molecular mechanism of energy usage and force
development in skeletal muscle.
Selected Publications:
(For a comprehensive list of recent publications, refer to PubMed, a service provided by the National Library of Medicine.)
Barnett Barnett VA. Cross-bridge cooperativity during isometric contraction and unloaded shortening of skeletal muscle. J Muscle Res Cell Motil. 2001;22(5):415-23.
Barnett, V.A., Ehrlich, A. and Schoenberg, M. (1992) Formation
of ATP-Insensitive Weakly-Binding Crossbridges in Single Rabbit
Posas Fibers by Treatment with Phenylmaleimide or Para-phenylenedimaleimide.
Biophysical Journal 61:358-367.
Barnett, V.A. and Thomas, D.D. (1989) Microsecond Rotational Motion
of Spin-labeled Myosin Heads During Isometric Muscle Contraction:
Saturation Transfer Electron Paramagnetic Resonance Spectroscopy.
Biophysical Journal 56:517-523.
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