Physical Chemistry
Laura Cooley
We
are studying a protein known as actin, which is responsible for
providing cells with their internal structure (cytoskeletal
structure). This protein polymerizes from a form known as
globular actin (G-actin) to form filamentous actin (F-actin).
F-actin filaments are about seven nanometers wide, and can grow quite
long. Like DNA molecules, they carry negative charges.
While actin filaments carry negative charges, under certain conditions they can nevertheless be made to aggregate (or form bundles.)
There are many reasons for studying these phenomena. For example,
the high viscosity of sputum in cystic fibrosis patients is caused in
part by aggregation of actin in the sputum.
•
Why does this happen?
•
Can it be reversed?
• How?
To
answer these questions requires basic knowledge of how and why bundles
form. Currently I am performing a study of how bundle size varies with
concentration of added magnesium ions, above threshold
concentration.
To
do this, I am using fluorescence microscopy. We measure the
fluorescence intensity across a bundle and figure out the relative size
from the relative fluorescence intensity. See image above.
Glênisson de Oliveira
In
the de Oliveira group, our main area of research is theoretical
chemistry. Historically, this label is distinct from
“computational chemistry” in that the former includes the development
of new methods and theories, while the latter consists of the use of
existing models to help elucidate practical issues in chemical fields.
In the area of methods development, our recent efforts have been
focused on the choice of mathematical functions (basis sets) used in
approximate solutions of the Schrödinger equation (ab initio
methods). We have modified existing basis sets to efficiently and
accurately determine the infinite basis set limits for physical
properties of molecules and molecular clusters. In one case, our
method became part of standard computational chemistry packages,
leading to some 300 citations to a single paper. More
specifically, we are interested in models that explicitly account for
electrostatic contributions to non-covalent interactions, including the
effect of polarizabilities, hyperpolarizabilities, and high order terms
of the permanent moment tensor (i.e. beyond dipole moments).
Chemical problems we address involve weak interactions and
clustering phenomena for small molecules – such studies are typically
put under the umbrella of “physical chemistry,” which is our area of
expertise. Other non-covalent interactions involving metal
complexes are also addressed.