Protein motors use chemical and electrochemical energy to generate mechanical forces. These forces drive intracellular motions that perform a variety of cellular functions; e.g., manufacturing ATP, pumping ions, shuttling proteins and chromosomes and extending cellular protrusions. Thus, the operating principles of these molecular machines are central to cellular physiology. Recent advances permit measuring forces and motions of single macromolecules on the scale of piconewtons and nanometers, and structural studies are revealing the detailed molecular architecture of protein motors. This has renewed the search for the physical principles that underlie mechanochemical energy conversion in macromolecular systems. It is now possible to make realistic models of molecular mechanochemical processes which can be related directly to observations, and which therefore can be tested experimentally. This project involves the construction of mathematical models to describe several important classes of molecular motors driven by nucleotide hydrolysis and transmembrane electromotive gradients. The particular systems to be addressed are (1) the V-ATPase ion pumps; (2)the bacterial flagellar motor; (3) the kinesin family; (4) the physical mechanisms that regulate the lamellipodial rotrusion motor of motile cells and the localization of membrane proteins that control these mechanochemical processes, and (5) the role of the fluid environment in molecular mechanochemical processes. Specifically, because many biomolecular motors operate in an aqueous environment and are mesoscopic in scale (large compared to water molecules but still small enough for Brownian motion to be important), Dr. Oster also proposes to develop computational methods for mesoscale biofluid dynamics with immersed molecular machinery. Such methods will also provide a means of studying intracellular water movements driven by osmotic forces. The proposed approach in each case is to begin by formulating stochastic equations that describe the mechanical behavior of the molecular structures. These equations are then subject to mathematical analyses where possible, and to numerical simulations in which parameters have been chosen using the best available experimental data. Results will be compared to data supplied by experimental collaborators and colleagues. Computer animations and other visual techniques will be used to present results in a broadly understandable manner.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM059875-03
Application #
6520080
Study Section
Molecular and Cellular Biophysics Study Section (BBCA)
Program Officer
Deatherage, James F
Project Start
2000-06-01
Project End
2005-05-31
Budget Start
2002-06-01
Budget End
2004-05-31
Support Year
3
Fiscal Year
2002
Total Cost
$236,088
Indirect Cost
Name
University of California Berkeley
Department
Public Health & Prev Medicine
Type
Schools of Earth Sciences/Natur
DUNS #
094878337
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Eide, Jonathan L; Chakraborty, Arup K; Oster, George F (2006) Simple models for extracting mechanical work from the ATP hydrolysis cycle. Biophys J 90:4281-94
Atzberger, Paul J; Peskin, Charles S (2006) A Brownian Dynamics model of kinesin in three dimensions incorporating the force-extension profile of the coiled-coil cargo tether. Bull Math Biol 68:131-60
Raj, Arjun; Peskin, Charles S (2006) The influence of chromosome flexibility on chromosome transport during anaphase A. Proc Natl Acad Sci U S A 103:5349-54
Adelman, Joshua L; Jeong, Yong-Joo; Liao, Jung-Chi et al. (2006) Mechanochemistry of transcription termination factor Rho. Mol Cell 22:611-21
Liao, Jung-Chi; Jeong, Yong-Joo; Kim, Dong-Eun et al. (2005) Mechanochemistry of t7 DNA helicase. J Mol Biol 350:452-75
Xing, Jianhua; Wang, Hongyun; Oster, George (2005) From continuum Fokker-Planck models to discrete kinetic models. Biophys J 89:1551-63
Sun, Sean X; Wang, Hongyun; Oster, George (2004) Asymmetry in the F1-ATPase and its implications for the rotational cycle. Biophys J 86:1373-84
Wolgemuth, Charles W; Oster, George (2004) The junctional pore complex and the propulsion of bacterial cells. J Mol Microbiol Biotechnol 7:72-7
Igoshin, Oleg A; Kaiser, Dale; Oster, George (2004) Breaking symmetry in myxobacteria. Curr Biol 14:R459-62
Igoshin, Oleg A; Goldbeter, Albert; Kaiser, Dale et al. (2004) A biochemical oscillator explains several aspects of Myxococcus xanthus behavior during development. Proc Natl Acad Sci U S A 101:15760-5

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