Research Report 2000 - MDC

disorders. Various MDC groups have
contributed in the elucidation of
monogenic diseases, including André
Reis and Herbert Schuster. The
current scientific challenge is to
delineate the genetic components of
complex traits. Extensive genetic field
working facilities established by
Herbert Schuster, a gene mapping
center with a capacity to generate
2,000,000 genotypes per day led by
André Reis, and the multiplex
sequencing technology for the
identification and typing of single
nucleotide polymorphisms,
established by Margret Hoehe, will
provide a framework for the
characterization of complex genetic
diseases in humans.
The group of Siegfried Scherneck is
studying genetic susceptibility factors
for breast cancer. His group has
analysed the genes of German
families that have a high risk of
developing breast cancer. The
majority of the families investigated
carry mutations in known cancer
susceptibility genes. However, every
forth family studied does not carry
these mutations and a novel breast
cancer susceptibility gene has been
located on chromosome 8. Moreover,
the group participates in a nationwide
program initiated and supported by
the “Deutsche Krebshilfe”. This
endeavor offers women options for
risk calculations, genetic counseling
and provides clinical and
psychological support.
Important links between the genetics
and structural biology components of
the program, as well as between
MDC-based basic science and patientoriented
research at the clinics, are
provided by the Bioinformatics Unit.
At present, the group operates at two
sites with a genetics section in Berlin
(Jens Reich) and a biocomputing
section at EMBL, Heidelberg, where
Peer Bork is currently a visiting
scientist. Combining both approaches,
the bioinformatics unit is evaluating
variations in the human genome that
are relevant to the diseases treated and
investigated at the Franz Volhard
Clinic (lipoprotein disorders,
arteriosclerosis and hypertension, with
Friedrich Luft) and at the Robert
Rössle Clinic (tumor and pertinent
normal tissue, with Peter M. Schlag).
The Structural Biology groups of
MDC use a wide range of
experimental techniques to study
problems of protein and nucleic-acid
structure, folding, dynamics and
function. Together with complementary
methods offered at the Forschungsinstitut
für Molekulare Pharmakologie
(FMP), they provide the Buch Campus
with expertise to address nearly all
aspects of structural biology relevant
to medicine and pharmacology.
In the Berlin Brandenburg area, these
groups are integrated in and provide
leadership for the Koordinationszentrum
Strukturforschung (KoSt), an
organization supported by the Senate
of Berlin. The aim of KoSt is to
coordinate structural analyses of a
wide range of objects, from
biomolecules to shapes, surfaces and
textures important in the materials
sciences. Responding to the
challenges posed by the international
genome programs, a Berlin-based
initiative has begun to set up a
structural genomics infrastructure for
the high-throughput structure analysis
of proteins following the sequencing
of their genes or cDNAs within the
German human genome project. This
initiative, the “Proteinstrukturfabrik”,
is coordinated at MDC and funded by
the BMBF.
Within the structural biology program
of MDC, four main lines of research
are being followed. (1) The analysis
of the three-dimensional structure of
proteins and nucleic acids by X-ray
diffraction methods is the central
theme of Udo Heinemann’s research.
Recent projects of his group have
addressed problems of specific
protein-RNA recognition, electron
transfer by [2Fe-2S] ferredoxins in
cytochrome P450 systems, in vivo
folding of engineered glycosyl
hydrolases, sex steroid transport in
plasma by the sex-hormone binding
globulin, and blood coagulation
mediated by tissue factor, a member
of the cytokine receptor superfamily.
Computer simulations of nucleic acid
structure and ligand binding (Heinz
Sklenar) provide valuable information
where experimental data are not
available or are inaccessible. Using
new algorithms for the treatment of
solvent electrostatics, molecular
simulations have been applied to the
functional analysis of gene regulatory
DNA sequences, the characterization
of non-canonical structural motifs in
RNA, and a binding study of singletoxygen
generating dyes to DNA.
(2) Protein misfolding events and the
resulting aberrant protein conformations
have received considerable attention
recently due to their relevance to
amyloidoses, a family of diseases
characterized by deposits of β-stranded
protein aggregates in tissue. Applying
a variety of experimental techniques,
the groups of Gregor Damaschun and
Heinz Fabian are studying the folding
pathways and kinetics of a number of
model polypeptides to help shed light
on productive folding and pathological
misfolding of proteins. (3) To fulfill
their diverse physiological functions,
proteins interact with many ligands.
These ligands vary widely in size
from small molecules to cellular
structures. The binding events are
characterized by very different time
scales and association constants.
Time-resolved Fourier-transform
infrared spectroscopy is being used to
study structural changes and reaction
intermediates associated with electron
transfer in cytochrome P450
(Christiane Jung). Antibody-peptide
interactions, the specific binding of
the tetracyclin repressor to operator
DNA and initiator-tRNA binding by
the initiation factor IF2 are being
investigated by circular dichroism,
fluorescence, infrared and Raman
spectroscopy as well as calorimetric
methods in Heinz Welfle’s laboratory.
Finally, analytical ultracentrifugation
is being employed by Joachim Behlke
to study the interaction of protein
domains with unusually structured
DNA, protein oligomerization and the
nucleation of protein crystal growth.
(4) In a large number of
collaborations with extramural and
MDC groups, protein chemistry,
peptide sequencing and mass
spectrometry (Brigitte Wittmann-
Liebold) have proven to be
indispensable tools for modern
molecular and cell biology research.
In addition, highly sensitive protein
2D-electrophoresis combined with
MALDI mass spectrometry are key
techniques in proteome research
where the goal is to establish protein
patterns characterizing cellular states,
such as apoptosis, or processes such
as cell differentiation and
development.
Carmen Birchmeier, Udo Heinemann,
Friedrich C. Luft, Jens Reich,
Ludwig Thierfelder
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