Physical Principles underlying
Molecular Motors
Living matter in action, at the
smallest length scale epitomized by
biological motors, operates in
nonequilibrium steady states (NESS).
In NESS, the detailed balance is
broken such that nonvanishing energy
and material currents are constantly
fed and flow out of the system. Together with the microscopic
underpinnings underlying the functions
of individual motors, we are
interested in quantifying how energy,
information, and material balance in
biological systems contributes to the
emergence of cellular organizations.
Structure,
dynamics, and function of human
chromosomes The
packaging of chromosomes, giant
chain molecules made of hundreds
of megabase-long DNA, into a small
volume is truly remarkable. Recent
advances in Hi-C and imaging
technique have ushered in a new
era of research on genome
organization, which is bound to
reveal the origin of the cell
type-dependent gene expression in
due course. Despite these
advances, our understanding of the
dynamics of chromosome/genome at
varying scales of space and time
is still in its infancy.
Seemingly daunting problem at a
first glance, polymer physics
idea and molecular simulations
provide glimpses into the link
between the spatiotemporal
dynamics of chromosome and its
characteristic chain organization.
We try to explore the effect of
physical/energetic constraints in
chromosome architecture on the
dynamics, and learn the physical
basis of gene expression.
Origin of heterogeneous and slow
dynamics in biomolecular
systems Single
molecule time trajectories of
biomolecules provide glimpses into
complex folding landscapes that are
difficult to visualize using
conventional ensemble measurements.
Recent experiments using single
molecule measurements
and theoretical analyses have
highlighted dynamic disorder in
certain classes of biomolecules,
whose dynamic pattern of
conformational transitions is
affected by slower transitions
between hidden internal states. In
recent years, we have not
only articulated the existence of
dynamical heterogeneity in Holliday
junction dynamics (Nature Chem.
(2012)) and in
kinesin function (Traffic
(2017)), but also developed theories
to extract the extent of
heterogeneity using
a single molecule force
spectroscopy (Phys.
Rev. Lett. (2014), PNAS (2017)). The issues of
properly analyzing dynamical
heterogeneity in the dynamics of
biomolecules and deciphering
microscopic underpinnings of the
heterogeneity are one
of the main research themes of
the group. Allostery
in biomolecules
Allostery refers to a
long-range communication between two
remote sites in biomolceuls. Key question
concerning allostery would be: For a given
conformational ensemble of a protein,
which are the key residue for allostery?
What are the allosteric signaling
pathways? Investigating a variety of
structural ensemble of protein with and
without cognate ligand we aim to decipher
the physical basis of allostery.
Contact
Information : Changbong Hyeon, Professor,
School of Computational Sciences, Korea
Institute for Advanced Study, Seoul 02455,
Korea +82-2-958-3810
(tel)