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Presents
the Friday Keck Center Teleconference*
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Life
In a Crowd: Macromolecular
Crowding and Confinement Effects on Protein Interactions in Living
Systems
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Margaret
S. Cheung, Ph.D.,
Assistant
Professor of Physics, University of Houston
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4:00
pm Friday
March.
23rd , 2007
(Refreshments
at 3:45)
5.521
Levin Hall
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Abstract: Biological
polymers carry out their functions in living systems where the
environment is very concentrated or crowded by macromolecules. The
volume fraction of these macromolecules that include proteins,
nucleic acids, lipid membranes, and cytoskeletons can be up to 40%
or more. In other words, physically, the composition of a cell is
more than "a sack of water"; its consistency is closer
to Jell-O. Experiments suggests that, because of this
macromolecular crowding effect that confines polymeric dynamics,
the kinetics and thermodynamics of protein folding and the
association rate constants of protein-protein interactions in a
cell (in vivo) are very different from that in a diluted test tube
(in vitro). In order to quantitatively understand macromolecular
crowding and confinement effects on protein dynamics, we used
coarse-grained models that physically captured interactions
between crowders and a protein. The folding rates of a model
protein nonmonotonically increased with the volume fraction of the
crowders. At lower volume fractions, depletion-induced attractions
from crowders could be mapped according to the spherical
confinement model. A result of spherical confinement was the
destabilization of denatured states by disallowing extended
configurations that were longer than the pore size. However, at
higher volume fractions, conformational fluctuations of a protein
were susceptible to the shape of the confining condition. Thus, an
approximation of the spherical confinement to mimic crowding
effects was no longer effective. Behaviors of transition states
and protein-protein interactions in a spherical confinement will
also be discussed.
(
http://phys.uh.edu/faculty.php?155622-961-5=mscheung
)
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The
Keck Friday Seminar*
schedule
for Spring 2007
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12-Jan
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Robert
Cox
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Functional
MRI
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19-Jan
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Ching Lau, Assoc Prof,
Pediatrics, Hematology/Oncology, BCM
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Novel
targets in pediatric brain tumors: from genomics to bedside
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26-Jan
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Irina
I. Serysheva
Baylor
College of Medicine
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Domain
Structure of RyR1 channel at Subnanometer Resolution
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2-Feb
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Poster winners from the
2006 Keck Annual Research Conference
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Matthew
Baker, Kexin Huang, & Jeffrey Reid
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9-Feb
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Mauro Ferrari,
Professor, Brown Foundation Institute of Molecular Medicine for
the Prevention of Human Diseases; Chairman, Dept. of Biomedical
Engineering, UTHSC-H
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Biomedical
Nonotechnology
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16-Feb
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Mike Mancini,
Associate Professor, Dept. of Molecular & Cellular Biology,
BCM
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Single cell
analyses of transcription using high throughput imaging
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23-Feb
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C. Thomas Caskey, Dir.
and COO, Institute for Molecular Medicine, UTHSC-H
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The Drug
Development Crisis: Efficiency and Safety
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2-Mar
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Jack Smith, Dean
& Professor, School of Health Information Sciences, UTHSC-H
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Issues
Related to Open Access and Clinical Data Repositories
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9-Mar
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Midterm
Recess
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16-Mar
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Vittorio Cristini,
Associate Professor, School of Health Information Sciences,
UTHSC-H
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Computational
modeling identifies morphologic predictors of tumor invasion
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23-Mar
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Margaret
Cheung, Assistant Prof, Physics, UH
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Life in a
crowd: macromolecular crowding and confinement effects on protein
interactions in living systems
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30-Mar
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Theodore
S. Jardetzky
Northwestern
University
Professor,
Biochemistry, Molecular Biology & Cell Biology
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TBA
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6-Apr
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Good
Friday
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13-Apr
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Keith Hodgson, Prof.
Chemistry, Stanford Synchrotron Radiation Laboratory, Stanford
University
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TBA
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20-Apr
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Stanley Lemon,
Dir, Institute for Human Infections and Immun; Professor, Internal
Medicine-Infectious Diseases, Microbiology, UTMB
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Interactions
of the hepatitis C virus RNA-dependent RNA polymerase NS5B with
the retinoblastoma tumor suppressor protein
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KECK/HAMP
Friday Seminars: http://xray.utmb.edu/keck
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Archived
Friday Seminar Webcasts Available:
http://cohesion.rice.edu/centersandinst/gcc/
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*Improved
clearer images: Now with POLYCOM's
DUAL STREAMING H.239 technology for clear
high-resolution slides plus video.
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