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Modeling of Biomolecular Systems Interactions, Dynamics, and Allostery Session IV Abstracts
What Was First, the Genetic Code or Its Products?
Ada Yonath
.
Weizmann Institute of Science, Rehovot, Israel.
Ribosomes, the universal cellular machines for translation of the genetic code into proteins,
possess spectacular architecture accompanied by inherent mobility, allowing for their smooth
performance as polymerases that translate the genetic code into proteins. The site for peptide
bond formation is located within a universal internal semi-symmetrical region. The high
conservation of this region implies its existence irrespective of environmental conditions and
indicates that it may represent an ancient RNA machine. Hence, it could be the kernel around
which life originated. The mechanistic and genetic applications of this finding will be discussed.
The Photosynthetic Membrane of Purple Bacteria as a Clockwork of Atomic and
Electronic Level Processes
Klaus Schulten
.
University of Illinois at Urbana-Champaign, Urbana, IL, USA.
The chromatophore of purple bacteria is a spherical bioenergetic membrane of 70 nm diameter
with (by area) 90% protein content involving about 130 large protein complexes. With each
chromatophore generated through invagination of the inner bacterial membrane, hundreds of
chromatophores provide a bacterium with energy in the form of ATP, the synthesis of ATP being
driven by sun light. The overall function in each chromatophore comes about through a
clockwork of intertwined physical processes organized through a multi-million atom
macromolecular structure. Recent progress has lead to a surprisingly rigorous description of key
aspects of chromatophore biology: the huge overall structure got resolved down to its atomic,
even electronic level, components; the physical mechanisms underlying the different
participating processes have been largely identified and proven through computer simulations;
the coupling of the different processes leading to a clockwork with robust and optimal
photosynthetic function has been described in principle. This clockwork involves: (1) the
quantum biological processes of light absorption, exciton formation, and coherent excitation
transfer arising in so-called light harvesting proteins; (2) coupled electron-proton transfer and
charging of the quinone-quinole pool achieved in a protein complex called the reaction center;
(3) discharging of the quinone-quinole pool and charging of the membrane voltage achieved
through electron-proton transfer realized in the bc1 protein complex; and (4) use of the
membrane voltage by a protein complex called ATP synthase. The lecture exploits the most
advanced molecular graphics achievable today (using the author's program VMD), and the most
rigorous computational description of the subprocesses possible today (using the author's
programs NAMD and PHI) offering views of the processes described as well as advanced and
detailed computational (in particular also quantum chemical) descriptions.
