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. 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. ATP hydrolysis is presumed to drive protein conformation changes that result in sliding or walking movements. Molecular movement occurs along a “track” Molecular movement occurs along a “track” The “track”, either an actin filament or a micro tubule, is a helical polymer that has intrinsic polarity. 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. Linear Protein Motor Types MYOSIN Moves toward fast-growing (+) end of actin filaments. DYNEIN Moves toward slow-growing (-) end of microtubules. KINESIN Moves generally toward (+) end of microtubules. 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. 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.” Unidirectional motion is produced by a pronounced conformational change in kinesin’s “neck linker.” (Vale & Milligan, 2000) ~80Å http://courses.nnu.edu/cm342jc/Term%20Projects/2001%20proj/collins.ppt

6. CATALYTIC CORE: allosteric domain containing MT and nucleotide binding regions. NECK LINKER: motion is produced by conformational change. COILED COlL: extends toward cargo. 1.) ATP binds to leading head, initiating docking of neck linker to tubulin. 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 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. 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+ Ion flux is driven by an electrochemical gradient controlled by H+ and Na+ This gradient consists of a voltage component and a concentration component 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+ 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 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 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 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 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 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” 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 Motor is about 500 nm across The rotor is between 100 and 300 nm long 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 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 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 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 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 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 EdinburghDavid A. Leigh 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. Future Projections http://bionano.rutgers.edu/Mavroidis_Final_Report.pdf