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Nano-Lab August 2003

Nano-Lab August 2003. Nano-scale motors. Molecular Motors. Biological Motors Background Three types of linear stepper protein motors Linear stepper motor: Kinesin Rotary propellers: bacterial flagella Laboratory made motors UC Berkeley University of Edinburgh/Bologna Cornell/UCLA

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Nano-Lab August 2003

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  1. Nano-Lab August 2003 Nano-scale motors

  2. Molecular Motors • Biological Motors • Background • Three types of linear stepper protein motors • Linear stepper motor: Kinesin • Rotary propellers: bacterial flagella • Laboratory made motors • UC Berkeley • University of Edinburgh/Bologna • Cornell/UCLA • Future Projections

  3. Background • Molecular motors are proteins that use ATP to carry out coordinated movements within cells. • ATP hydrolysis is presumed to drive protein conformation changes that result in sliding or walking movements. • Molecular movement occurs along a “track” • The “track”, either an actin filament or a micro tubule, is a helical polymer that has intrinsic polarity. http://courses.nnu.edu/cm342jc/Term%20Projects/2001%20proj/collins.ppt

  4. DYNEIN Moves toward slow-growing (-) end of microtubules. MYOSIN Moves toward fast-growing (+) end of actinfilaments. KINESIN Moves generally toward (+) end of microtubules. Linear Protein Motor Types http://courses.nnu.edu/cm342jc/Term%20Projects/2001%20proj/collins.ppt

  5. Kinesin • Kinesin “walks” along the microtubule (MT) protofilament, stepping from one tubulin subunit to the next. • Unidirectional motion is produced by a pronounced conformational change in kinesin’s “neck linker.” ~80Å (Vale & Milligan, 2000) http://courses.nnu.edu/cm342jc/Term%20Projects/2001%20proj/collins.ppt

  6. 1.) ATP binds to leading head, initiating docking of neck linker to tubulin. COILED COlL: extends toward cargo. CATALYTIC CORE: allosteric domain containing MT and nucleotide binding regions. NECK LINKER: motion is produced by conformational change. http://courses.nnu.edu/cm342jc/Term%20Projects/2001%20proj/collins.ppt

  7. Bacterial Flagella • Molecular engine powered by the flow of ions across the inner, or  cytoplasmic, membrane of a bacterial cell envelope • Each motor drives a protruding helical filament, and the rotating filaments provide the propulsive force for cells to swim.  Artistic version of flagella motor http://www2.physics.ox.ac.uk/biophysics/research/flagellar.html

  8. Bacterial Flagella • Ion flux is driven by an electrochemical gradient controlled by H+ and Na+ • This gradient consists of a voltage component and a concentration component • The inside of the cell is typically at an electrical potential about 150mV below the outside and has a slightly lower concentration of H+ or Na+ http://www2.physics.ox.ac.uk/biophysics/research/flagellar.html http://www.id.ucsb.edu/fscf/library/battson/stasis/4.html

  9. Bacterial Flagella • Filaments rotate at speeds up to 1000 Hz in swimming cells • The rotating heart of the motor is a set of rings in the cytoplasmic membrane • This rotor is surrounded by 8-16 torque generators, proteins MotA and MotB, anchored in the cell wall http://www2.physics.ox.ac.uk/biophysics/research/flagellar.html

  10. Laboratory Nano-motors UC Berkeley Gold Nano-motor • Gold rotor on a multilayered Carbon nano-tube shaft • The rotor, nano-tube anchors and stators were constructed around the carbon nano-tube, using electron beam lithography and silicon etching techniques, that had been deposited on a silicon wafer http://www.berkeley.edu/news/media/releases/2003/07/23_motor.shtml

  11. UC Berkeley Gold Nano-motor • Using an electric jolt to jerk the rotor, the nested nano-tube outer walls were broken free allowing the rotor to spin on the nano-tube “bearings” • Motor is about 500 nm across • The rotor is between 100 and 300 nm long http://www.berkeley.edu/news/media/releases/2003/07/23_motor.shtml

  12. UCLA/Cornell University Carlo Montemagno • Nickel rotors about 700 nm long are attached to the shaft molecule • Shaft is rotated by the six cylindrical structures and can be turned off or on by adding or removing zinc from the solution • A histidine peptide allows the molecular motor to adhere to nanofabricated patterns of gold, copper or nickel Nanofabricated nickel post http://www.news.cornell.edu/releases/sept99/bio_nano_mechanical.hrs.html http://www.sciam.com/article.cfm?articleID=000988D5-647B-1C75-9B81809EC588EF21&pageNumber=2&catID=4

  13. University of Edinburgh/Bologna • Two smaller rings move around the larger “cycle” ring • Light, heat or chemical stimuli drive the rings around the cycle by altering the properties of each chemically distinct site chemistry professor David A. Leigh University of Edinburgh http://www.chem.ed.ac.uk/leigh/ http://pubs.acs.org/cen/topstory/8128/8128notw9.html http://www.nanotechweb.org/articles/news/2/7/9/1

  14. http://bionano.rutgers.edu/Mavroidis_Final_Report.pdf Future Projections

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