The Grandpierre Lecture
"Polymer solutions as a model cytoplasm in primitive artificial cells based on lipid vesicles"
Presented by Christine Keating, Penn State University
Abstract:
Chemists have long sought to understand the natural world through
synthesis. In our lab, we carry on this tradition not by making and
breaking chemical bonds but rather by preparing simple experimental
models of biological cells based on physical and materials chemistry.
This lecture will describe efforts to prepare artificial cells and
cell-like environments that capture one or more key features of their
living counterparts.
The interior of biological cells is crowded
with macromolecules, heterogeneous in composition, and dynamic. These
aspects of intracellular environments dramatically impact their physical
chemistry and are crucial to cell function. In our simple model
systems, macromolecular crowding is provided by polymers such as
polyethylene glycol or dextran (a polyglucose). When both polymers are
present at sufficient concentrations, the solution can phase separate to
form two distinct aqueous phases, each enriched in one of the polymers.
Aqueous phase separation is common in macromolecule solutions and has
been observed in living cells. In our work, the formation of
dextran-rich and PEG-rich phase domains provides control over the local
concentration of not only the polymers themselves but also any molecules
that accumulate in one of the phases by partitioning. This
compartmentalization of nucleic acids or proteins can be used to drive
reactions that are concentration dependent.
Encapsulation of the
aqueous two-phase systems within lipid vesicles having a semipermeable
membrane provides a primitive model of biological cells capable of
microcompartmentalization, polarity, and asymmetric division. The
synthesis and characterization of artificial cells and cell-like
environments may provide new insight into how fundamental chemical and
physical phenomena common to all cells may have shaped the development
of early cells and could still underlie many of the seemingly complex
behaviors of modern cells.
Hosted by the Chandler Society
Thursday, February 21, 2013 at 4:30pm
Room 209 Havemeyer
