Melih K. Sener
From a certain practice run for
a 'Physics in People, Physics in Plants' class...
(more semi-random images )
Background
-
I have recently moved to
Cornell University and the Weill Medical College
to join the group of
Harel Weinstein.
I will update my webspace with my more recent research activities
as I find time.
I was a post-doctoral researcher in the Theoretical and Computational Biophysics Group of the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign. Coming from a theroretical physics and mathematics background, my current research interests include kinetic properties and evolution of massive excitation transfer networks in photosynthesis as found in multi-protein light harvesting assemblies. I have also been involved in many outreach activities to bring science to broad audiences.
Education
Ph. D. in Physics State University of New York at Stony Brook, Aug. 1999
M. A. in Physics State University of New York at Stony Brook, Dec. 1996
B. Sc. in Physics and Mathematics
(double major)
Middle East Technical University, Ankara/Turkey, May. 1994
The sun is not only the author of visibility in all visible things,
but of generation and nourishment and growth.
- Plato (quoted by
Govindjee )
Photosystem I: one of the two major protein-pigment
complexes utilized by oxygenic photosynthetic species for harvesting sunlight.
The trimeric assembly of photosystem I shown here
contains 288 chlorophylls (represented in bond representation by their
porphyrin rings) that form an antenna array along which excitation
energy resulting from the absorption of a photon
migrates to a reaction center, where it is utilized for
electron transfer and subsequent 'charging up' of a cells ATP synthesis mechanism.
This process is the main source of energy in the biosphere.
Figure made with VMD.
Light harvesting complexes provide fascinating challenges to biophysicists. With the availability of recent atomic structures for protein-pigment complexes such as photosystem I in cyanobacteria (Jordan et al., Nature 2001) and plants (Ben-Shem et al., Nature 2003), it is possible to form a comprehensive picture of the light absorption and excitation migration processes based on an atomic level quantum mechanical description. This kind of structural analysis not only provides a rigorous test for our understanding of the physics of these mechanisms through a comparison to spectroscopy and kinetics experiments, but it also forms a framework within which the organizational principles for multi-component pigment-protein assemblies can be investigated.
Some of the questions that we aim to address in our studies are:
- How does a protein-pigment complex survive thermal disorder? How do thermal fluctuations affect the overall efficiency of the light harvesting process?
- What is the level of error tolerance of the pigment network? How does component loss affect overall function?
- Are there signs of optimality in the seemingly random network geometry of the pigments as compared to alternative geometries? What is the hierarchy of constraints on system evolution?
- What are the principles for the evolution of network geometry of pigments? As plants diverged from cyanobacteria about one billion years ago, a comparison of the two light harvesting networks provide us with a first glance at these principles.
A more detailed yet colloquial discussion of my recent research can be found at: Organization of energy transfer networks in photosynthesis.
My personal musings on challenges in biology that shape my long term research goals, especially in regards to a need for a proper mathematical framework relevant for the organization and evolution of biological systems, can be found at: Manifesto of a biophysicist.
My research as featured in previous
group highlights
'Exciting Biology and Hot Physics Meet'
Thermal disorder is an ever-present challenge for all organisms - and the
scientists who model them. Quantum field theory tools come to the rescue
of modelling thermal effects in electronically
excited bioenergetic systems.
'Unbreakable Biological Solar Cell'
"If it ain't broke, don't fix it!" By observing the network topology
of excitation migration pathways in a massive light harvesting assembly
and comparing it to alternative configurations we uncovered signs of
robustness and optimality in chlorophyll network architecture.
'Finding the Path'
A novel method is presented for finding representative reaction paths
for biological processes based on mean first passage times.
'Bringing Physics To Life'
This recent brochure of our groups collective work also features some of my research highlights.
'Evolution Shaped by Physics'
How biological networks evolve and how physical constraints that act upon
their dynamics shape this evolution is poorly understood.
A glimpse of insight can be gained by a comparison
of energy transfer networks from related species as presented in this
'Tale of Two Photosystems'.
Publications
Cited 202 times. (as of December 2004, source: ISI Web of Science and SPIRES-HEP databases)-
Comparison of the light harvesting networks of plant and cyanobacterial photosystem I.
Melih K. Sener, Craig Jolley, Adam Ben-Shem, Petra Fromme,
Nathan Nelson, Roberta Croce, and Klaus Schulten.
Biophysical Journal, 89:1630-1642, 2005.
Physical principles of efficient excitation transfer in light harvesting.
Melih Sener and Klaus Schulten. In David L. Andrews, editor, Energy Harvesting Materials.
World Scientific, Singapore, 2005. In press.
Excitation migration in trimeric cyanobacterial photosystem I.
Melih K. Sener, Sanghyun Park, Deyu Lu, Ana Damjanovic, Thorsten Ritz,
Petra Fromme, and Klaus Schulten.
Journal of Chemical Physics, 120:11183-11195, 2004.
Reaction paths based on mean first-passage times.
Sanghyun Park, Melih K. Sener, Deyu Lu,
and Klaus Schulten. Journal of Chemical Physics, 119:1313-1319, 2003.
Robustness and optimality of light harvesting in cyanobacterial
photosystem I.
Melih K. Sener, Deyu Lu, Thorsten Ritz, Sanghyun Park, Petra Fromme, and Klaus Schulten.
Journal of Physical Chemistry B, 106:7948-7960, 2002.
A general random matrix approach to account for the effect of static disorder
on the spectral properties of light harvesting systems.
Melih Sener and Klaus Schulten. Physical Review E, 65:031916, 2002. (12 pages).
Ph.D. Thesis
Universality in Random Matrix Models of
Quantum Chromodynamics.
Melih K. Sener, Stony Brook, August 1999.
Universality in random matrix theories and quantum choromodynamics
Universality in Chiral Random Matrix Theory at beta =1 and beta =4.
Melih K. Sener and Jacobus J. M. Verbaarschot.
Physical Review Letters, 81:248-251,1998.
Universality of Correlation Functions in Random Matrix Models of QCD.
Andrew D. Jackson, Melih K. Sener, and Jacobus J.M. Verbaarschot.
Nuclear Physics B, 506:612-632,1997.
Finite volume partition functions and Itzykson-Zuber integrals.
Andrew D. Jackson, Melih K. Sener, and Jacobus J. M. Verbaarschot
Physics Letters B, 387:355-360,1996.
Universality near zero virtuality.
Andrew D. Jackson, Melih K. Sener, and Jacobus J. M. Verbaarschot
Nuclear Physics B, 479:707-726,1996.
Energy transfer networks in photosynthesis, their dynamics and evolutionary principles, thermal disorder, kinetic methods
Contact information
address: Beckman Institute, 405 N. Mathews, Urbana, IL 61801.tel: 217-244 1733 fax: 217-244 6078
email: (my first name) at ks.uiuc.edu
The occasional little personal snippet
tango@verde
A series of tango dances that I used to host
regularly at a local art gallery.
The Writer's Almanac.
My single most favorite website on the whole web.
Its archive has many a hidden gem in the way of poems and
biographical tidbits.
Tango in town.
This site from one of my instructors has a personal
perspective on tango in Champaign-Urbana with its many colorful dancers.
An experimental determination of Pi.
A cute little mathematics 'experiment'. This was the first web
page I ever created.
'... the colors and the lines that trace the past
will in the semi-darkness form a face ...'
If I were to pick only one poem for the end of time...