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Biophysics of Proteins at Surfaces: Assembly, Activation, Signaling
Poster Abstracts
21-POS
Board 21
Understanding Structural Mechanism of β
2
-Adrenergic Receptor Based on Water Molecule
Using All-Atom Molecular Dynamics (MD) Simulation
Songmi Kim
, Changbong Hyeon.
Korea Institute for Advanced Study, Seoul , South Korea.
G protein-coupled receptors (GPCRs) are membrane proteins and responsible for various cell
response including vision, smell, hormones, odorants, neurotransmitter and other factors. The
GPCRs have conformational change when binding ligand or signal molecule to transmit signals
form extracellular to intercellular regions. Several GPCR crystal structures revealed that the
activation of GPCRs is mediated by structural water molecules. To understand structural
mechanism focused on water molecules within β
2
-adrenergic receptor (β
2
AR), we constructed
systems for different states. We have performed 1μs all-atom MD simulation for each system in
membrane environment. The dynamics of water molecule in β
2
AR and structural analysis have
been carried out by time correlation function of contacts between residue and water molecules
and by calculating the water penetration.
24-POS
Board 24
DMSO Disorders Water Structure and Enhances Water Diffusion Near Phospholipid
Bilayer Surfaces
Yuno Lee
, Changbong Hyeon.
Korea Institute of Advanced Study , Seoul, South Korea.
Dimethyl sulfoxide (DMSO) prevents ice formation by disrupting the hydrogen bond network
among water molecules. Despite its broad use as a cryoprotectant and long-lasting efforts to
probe water dynamics in the presence of DMSO, the microscopic underpinnings by which
DMSO prevents ice formation on cell surfaces are not fully understood. Here, using all atom
molecular dynamics simulations of POPC/water systems at varying DMSO concentrations, we
probe the structural and dynamical properties of water and DMSO in the vicinity of phospholipid
bilayers. Our study is consistent with the recent studies pointing to DMSO-induced dehyration,
but critically reveals the presence of fine structures in hydration layer near bilayer surfaces.
DMSO has a unique property that the extent of depletion from solvent-bilayer interfaces, which
leads to preserving the hydration layer, is more long-ranged and greater than other cosolvent
such as sucrose. As a consequence, the mobility of surface water at increased DMSO
concentrations is less affected than that of the bulk water in DMSO solution, enhancing the
surface water diffusion relative to the bulk.