The 8th
Annual
NC
Undergraduate
Summer Research Symposium
University Honors
Program/CALS Honors Program
abstracts
Abstracts are listed in
alphabetical order by the last name of the corresponding author.
|
Parikh, Mihir K. |
|
|
Home Institution: |
NCSU |
|
Program: |
University Honors Program/CALS Honors Program |
|
College: |
CALS |
|
Department(s): |
Molecular and Structural
Biochemistry |
|
Research |
Carla Mattos/Molecular and Structural Biochemistry Greg Buhrman/Molecular and Structural Biochemistry |
|
Title of Presentation: |
Purification and Raf
Binding of the Double Ras Mutant (Q61L/Y32F) |
Ras GTPase is an important transducer molecule in the
Raf/MEK/ERK signal transduction pathway that plays an indispensible role in
cellular growth and differentiation. The
Ras signal transduction pathway is upregulated in at least 30% of all forms of
cancer. In most cases, upregulation of
the pathway is due to point mutations in Ras at positions 12, 13 and 61 that
result in a decrease in intrinsic and Ras-GAP catalyzed GTP hydrolysis. Specific point mutations at residues Gln61 to
Leu61 and Tyr32 to Phe32 result in a decrease of intrinsic GTPase activity by a
factor of 20 and 2 respectively. Binding
of the primary downstream effector protein Raf to Ras
further reduces the GTPase activity of the Leu61 mutant, but has the opposite
effect on the Phe32 mutant, increasing the hydrolysis rate of the Phe32 mutant
to wild type levels. The main goal of
this experiment is to solve the x-ray crystal structure and determine the
hydrolysis rates of the double mutant RasQ61L/Y32F alone and when bound to Raf. The double mutant was grown and overexpressed in E.
coli and purified by anion exchange and gel filtration chromatography. The GDP bound to the Ras protein was
exchanged for a non-hydrolyzable GTP analog GppNHp. Initial crystallization
trials with the double mutant have found micro and quasi crystals. Optimization of these experiments should lead
to large, single crystals suitable for x-ray diffraction experiments. A Ras-Raf binding experiment showed a Ras-Raf
complex peak indicating that the double mutant binds to Raf. Determining the hydrolysis rate of the double
mutant in the presence and absence of Raf will help to
clarify the role of Tyr32 in intrinsic GTP hydrolysis.
|
Tamborini, Stephanie A. |
|
|
Home Institution: |
NCSU |
|
Program: |
University Honors Program/CALS Honors Program |
|
College: |
CALS |
|
Department(s): |
Biological Sciences |
|
Research |
Elizabeth A. Turpin/Pfizer Poultry Health |
|
Title of Presentation: |
Expression of Newcastle
Disease Virus Fusion Gene |
Newcastle disease virus (NDV), a devastating disease
affecting all ranges of poultry, causes high levels of morbidity and mortality
worldwide. The fusion protein in
Newcastle disease virus is proven to, after cleavage, initiate infection,
acting as a determinant of virulence. This initiation occurs by the fusion of
the virion membrane with the host cell membrane followed by virus entry into
the cell. At the fusion protein cleavage site, the presence of particular amino
acids determines the virulence of NDV.
Vaccines containing fusion gene (F) (LaSota isolate of NDV) in chickens
have been shown to provide immunity to the virus. The goal of this project was to develop an
assay to detect antibodies to NDV-F. The expected outcome of this project was
to generate a GFP vector containing F in order to develop a serological assay
specific for antibodies to NDV-F.
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Last modified June 2009 by Sharon E. Hunt