Transcript Nobel Prize in Chemistry 2006 Roger D Kornberg Molecular

Nobel Prize in Chemistry 2006
Roger D Kornberg
Molecular basis of eukaryotic
transcription
Summary of his contributions
• ~75 published articles last 10
years
• Developed a yeast system for
production and purification of
RNA polymerase II
• Discovery of the Mediator
complex in eukaryotic
transcription
• Structure determination of more
than a dozen new crystal
structures of RNA polymerases
with DNA, RNA inhibitors and
protein complexes
Central Dogma
DNA
RNA
Protein
Prokaryotic transcription
RNA polymerase
containing 5 subunits
One polymerase for all
transcription
s-factor recognize
promoter region on
the DNA
Eukaryotic transcription
RNA polymerases I,II
and III
RNA polymerase II, 12
subunits,
MW~0.5MDa
5 transcription factors,
TFIIB,E,F,H and TBP
Mediator complex
Eukaryotic transkription
Structure of RNA polymerase II
"If any enzyme does the cell's heavy lifting, it's
RNA polymerase II. Its job: getting the synthesis
of all the proteins in higher cells under way by
copying their genes into RNAs, and doing it at just
the right time and in just the right amounts. As
such, pol II, as the enzyme is called, is the heart of
the machinery that controls everything that cells
do--from differentiating into all the tissues of a
developing embryo to responding to everyday
stresses. Now, cell biologists can get their best
look yet at just how the pol II enzyme of yeast
and, by implication, of other higher organisms
performs its critical role."
Jean Marx Science (2001), Apr20, 411-414
Xray structure determination
•Protein crystals
•Collecting data
•Determination of
the structure
Xray structure determination
•Collecting
data
Xray structure determination
•Determination the structure
Result
Electron density map
of the structure
Structure determination of
RNA polymerase II
Resolution down to 2.8 Å
10 subunits ~3500 amino acid residues
Collected data on synchrotron
Large unit cell (a=122.7 Å,b=223.0 and c=376.1)
The ”core” consist of RpbI (green and RpbII (cyan)
Illustrations from: Aaron Klug, Science 2001, 292, 1844-1846
RNA Polymerase II (yeast)
RNA polymerase II
RNA polymerase II
RNA polymerase II in action
Inhibitor of RNA polymerase II
Binding of a-amanitin to the
active site of RNA polymerase II
”Proofreading” of an
incoming nucleotide
Close-up view of ”proofreading”
(matched nucleotide, UTP)
Close-up view of ”proofreading”
(mismatched nucleotide, ATP)
Overlay matched/mismatched
nucleotide
Concluding remarks
• Molecular understanding of promoter
recognition
• Mechanism for initiation, translocation
• Mechanism for selection of an incoming
ribonucleotide complementary to template
DNA
• Future: Role of transcriptionfactors and
Mediators in regulation
Thanks for listening.....