Dr. Jennifer Lillig
and
group

The re-emergence of bacterial pathogens as a
significant threat to public health has lead to an increased awarness
of food safety. One of the most common food-borne pathogens is
Listeria monocytogenes, a bacteria
found to contaminate a variety of raw and processed foods including
vegtables, meats, and dairy products. Listeria infection can
result in a
variety of illnesses ranging in severity from fever and nausea to
meningitis and fetal miscarriage. In the past decade it has been
found that lactic acid bacteria, common food borne bacteria that are
non-pathogenic, produce small peptides termed bacteriocins, that kill
Listeria. Work in our lab
focuses on understanding the key features of these molecules that allow
them to target and kill competing bacteria such as Listeria. This
work can in
turn aid in the further development of these molecules as both potent
and safe drugs and food preservatives in the endevor to find new means
of fighting and preventing human disease.
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Meng-Chih Su and group

There is considerable interest in understanding and
characterizing protein adsorption to substrate surfaces because of
applications
in biosensors, biomedical devices and other biotechnologies (protein
chip
technologies). Many of these protein
chip technologies are based upon adsorbing or attaching a protein to a
solid substrate. Therefore, the
understanding of the fundamental principles governing the surface
adsorption
will improve our control of growing proteins on various substrates
which is
crucial to protein chip technologies. This
is the main theme of our research.
Denaturation effect on surface bound
proteins is studied in
this research group with use of prototype heme protein cytochrome c on
fused
silica surface. Using a high sensitivity
optical technique, attenuated total reflection (ATR) polarization
spectroscopy,
it is now possible to characterize monolayer
heme protein adsorption on the surface and hence focus on the
protein-surface
interactions. Thermodynamics and energy
transfer involved in the surface adsorption are studied through
adsorption
equilibrium constants, surface packing density, and molecular
orientation of
protein coverage on the surface. Further
chemical changes in the solution around the surface can cause
denaturation to
protein already on the surface, similar to the effect occurring in the
biological system. Therefore, the
conformational study of surface bound protein under these conditions is
closely
related to its native biological environment.
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Dr Carmen Works and group

My expertise
and research
interests lie in the area of reaction mechanisms involving transition
metal
chemistry and the importance of transition metal ions in biological
systems. I
have three projects that contribute to this
subfield of inorganic chemistry. Two of
these projects focus on the role of chromium ions in biological
systems.
The third project examines the photochemistry
of a model for the active site of the iron-only hydrogenase, an enzyme
involved
in the oxidation of molecular hydrogen.
A) Chromium(III) binding
proteins
Chromium can exist in
many
different forms but the most stable and common are chromium (VI) and
chromium
(III) ions. Chromium (VI) is a
particularly dangerous environmental
pollutant due to its carcinogenicity and water solubility. Chromium
(VI) is a
strong oxidizing agent and inside biological systems participates in a
string
of complex redox reactions. Products of
these reactions include chromium (III) DNA complexes, which are often
discussed
in the literature. My research at SSU has shown that chromium (III) can
also
form protein complexes after exposure to chromium(VI) . My
working hypothesis is that these chromium
(III) proteins are formed to prevent chromium (VI) from reacting with
DNA, as a
possible detoxification mechanism. In
order to determine if these chromium (III) protein complexes serve a
detoxification role, I have designed experiments to isolate and study
the
chromium (III) proteins that form in bovine liver after exposures to
chromium
(VI). In order to understand the
function of these metallo-proteins, their structural information must
first be
determined, which is the long-term goal of my research in this area.
B)
Chromate Reductase
Bacteria can rapidly evolve
to tolerate extreme chemical environments. This
has become important in bioremediation of polluted
soil and
water. The chromate reductase project is
concerned with studying the mechanisms that some bacteria utilize to
live in
high chromium (VI) environments. I am
particularly interested in bacteria that can reduce toxic chromium (VI)
to the
less toxic chromium(III) form. This
reduction process can only occur through a catalyzed reaction pathway,
utilizing a type of enzyme called chromate reductase. My research
group at SSU has identified a new
bacteria, Pseudomonas Veronii
that is capable of reducing chromium (VI),
indicating the presence of a chromate reductase. We
have performed a partial purification of
the enzyme from Pseudomonas Veronii
and the initial studies on the enzyme kinetics. The
current goal for this project is the complete
purification and
structural characterization of Pseudomonas
Veronii. The long-term goal for this project is to understand the
functional role of this enzyme.
C)
Photochemistry of m-(1,3-propanedithiolato)-hexacarbonyldiiron
The focus of
this project is
the photochemical reactivity of
m-(1,3-propanedithiolato)-hexacarbonyldiiron.
This compound is a structural and functional
model for the active site of iron-only hydrogenase. Iron-only
hydrogenase is an enzyme that
catalyzes the reversible oxidation of molecular hydrogen and is
responsible for
most of the bio-processing of hydrogen. The
photochemical experiments in this project could lend
insight into
how bacteria use hydrogen as a fuel.
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