BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Studying single molecule dynamic with local probe techniques - Pro
 fessor Heinrich Hoerber\, HH Wills Physics Laboratory\, Tyndall Avenue\, B
 ristol BS8 1TL\, UK
DTSTART:20070302T141500Z
DTEND:20070302T151500Z
UID:TALK6096@talks.cam.ac.uk
CONTACT:Jurij Kotar
DESCRIPTION:Local probe techniques (LPTs) extend our sense of touching int
 o the micro- and nano-world and in this way provide complementary new insi
 ght into the world we see with other microscopic techniques. Touching thin
 gs is an essential prerequisite to manipulate them and the ability to feel
  and manipulate single molecules or atoms for sure marks another revolutio
 nizing step in science. Experiments at the nanometer scale provide a compl
 ete new view on molecular processes hidden before in ensemble averages. As
  never all components of an ensemble can be forced into the same state\, i
 nformation about the time behavior of the individual components is lost. W
 ith LPTs we have a powerful tool to study functional cycles of single mole
 cules and to get new insight into their structure and function relation.\n
 Especially one of these LPTs\, the atomic force microscope (AFM) in its fo
 rce spectroscopy mode\, has meanwhile become a widely used tool to study m
 echanical properties of single molecules. With a further improved AFM we c
 ould elucidate the structural basis of the elastic properties of spectrin 
 repeats. Three-dimensional analysis of thermal position fluctuations also 
 can reveal mechanical properties of single molecular structures. We develo
 ped a new local probe instrument\, the photonic force microscope (PFM)\, t
 o make this possible. Thermally excited position fluctuations of an optica
 lly trapped bead tethered to a microtubule or actin filament by a single m
 olecular motor can be recorded. The position fluctuations transform into t
 hree-dimensional energy profiles using Boltzmann’s equation\, with a res
 olution of one tenth of the thermal energy. From such profiles\, force ver
 sus extension or stiffness versus extension profiles can be calculated alo
 ng arbitrary paths in three dimensions. The changes in these profiles with
 in the functional cycle of the molecular motor provide new insight how the
 rmal and chemical energies drive its movement.
LOCATION:IRC in Superconductivity Seminar Room\, Cavendish Laboratory
END:VEVENT
END:VCALENDAR