New Materials Design and Synthesis (Chemistry)
KAWAKAMI Laboratory
<Major Research Areas>Biophysics,
Single Molecule Measurement, Protein Folding
Single Molecule Dynamics of Biomolecules with AFM
Research activity
In order to understand the phenomenon of life, the elucidation
of the function of
each biomolecule is of great importance. The functions of protein
molecules, which play essential roles in the cell, have been
studied intensively. To carry out their biological function,
most protein molecules have to fold into a unique and highly-ordered
structure, and consequently much work has involved the determination
of the three dimensional structures of proteins. However, the
three-dimensional structure of proteins reveals only the “static”
properties of proteins and not the dynamic “fluctuations” of
their structures that are so important to their biological
function.
Until recently,
almost all measurements
of protein dynamics
have been obtained using ensemble measurements. These techniques
yield the average properties of the system: information about
individual molecules is hidden, and rarely populated conformational
states, which might be of functional relevance, are extremely
difficult to characterise. Techniques which can explore the
behaviour of single molecules are, therefore, essential for
developing new insights into the relationship between the dynamics
and function of proteins.
Single molecule
techniques such as
force mode AFM and optical tweezers have recently been used
to investigate the mechanical properties of various kinds of
biomolecules, but these techniques are not capable of investigating
the “internal” dynamics of molecules.
The aim of this
study is to develop
a novel technique which is capable of measuring the viscoelasticity
of a single molecule using the thermally or externally driven
motion of an AFM cantilever. Quantitative analysis of single
molecule viscoelasticity provides dynamic information on the
minor intra-molecular motions of protein molecules, which are
expected to be important to their biological function. Using
the single molecule viscoelasticity instrumentation, a novel
single molecule manipulation technique will be developed that
can control the reaction pathway of a single molecule leading
to the formation of
a structure.
Equipment
Highly sensitive Atomic Force Microscopes (Digital Instruments:
Picoforce, Asylum: MFP-1D)
Atomic Force Microscopy, Single Molecule Dynamics, Protein Folding
<Contact>
Masaru Kawakami / E-mail:kmasaru@jaist.ac.jp TEL:+81-761-51-1593 FAX:+81-761-51-1149
The main research achievements in the past five years
- M. Kawakami and Y. Taniguchi, Recent Advances in Single-Molecule Biophysics with the use of Atomic Force Microscopy, John Wiley & Sons Inc., in press (2011)
- Y. Taniguchi and M. Kawakami，Application of HaloTag protein to covalent immobilisation of recombinant proteins for single molecule force spectroscopy, Langmuir，26，13，10433-10436，(2010)
- Y. Taniguchi, B. S. Khatri, D. J. Brockwell, E. Paci and M. Kawakami，Dynamics of the coiled-coil unfolding transition of myosin rod probed by dissipation force spectrum，Biophysical Journal，99，257-262，(2010)
- Kawakami, M., Taniguchi, Y., Hiratsuka, Y., Shimoike, M. and Smith, D. A., Reduction of the damping on an AFM cantilever in fluid by the use of micro pillar stage, Langmuir, 26，2， 1002-1007，(2009)
- D. P. Sadler, E. Petrik, Y. Taniguchi, J. R. Pullen, M. Kawakami, S. E. Radford and D.J. Brockwell, Identification of a Mechanical Rheostat in the Hydrophobic Core of Protein L, Journal of Molecular Biology, 393, 1, 237-248 (2009)
